TCShower.cxx

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#include "larreco/RecoAlg/TCAlg/TCShower.h"
#include "cetlib/search_path.h"
#include "messagefacility/MessageLogger/MessageLogger.h"

#include "larcorealg/Geometry/GeometryCore.h"
#include "larcorealg/Geometry/TPCGeo.h"
#include "larcoreobj/SimpleTypesAndConstants/geo_types.h"
#include "lardataalg/DetectorInfo/DetectorPropertiesData.h"
#include "lardataobj/RecoBase/Hit.h"
#include "larreco/RecoAlg/TCAlg/DebugStruct.h"
#include "larreco/RecoAlg/TCAlg/PFPUtils.h"
#include "larreco/RecoAlg/TCAlg/TCShTree.h"
#include "larreco/RecoAlg/TCAlg/TCVertex.h"
#include "larreco/RecoAlg/TCAlg/Utils.h"

#include <algorithm>
#include <array>
#include <bitset>
#include <climits>
#include <cmath>
#include <iomanip>
#include <iostream>
#include <string>
#include <utility>
#include <vector>

#include "TMVA/Reader.h"

namespace tca {

  using namespace detail;

  void ConfigureMVA(TCConfig& tcc, std::string fMVAShowerParentWeights)
  {
    // Define the reference to the MVA reader used to determine the best
    // shower parent PFParticle
    cet::search_path sp("FW_SEARCH_PATH");
    if (!tcc.showerParentReader) return;
    std::string fullFileSpec;
    sp.find_file(fMVAShowerParentWeights, fullFileSpec);
    if (fullFileSpec == "") {
      tcc.showerParentReader = 0;
      return;
    }
    tcc.showerParentVars.resize(9);
    tcc.showerParentReader->AddVariable("fShEnergy", &tcc.showerParentVars[0]);
    tcc.showerParentReader->AddVariable("fPfpEnergy", &tcc.showerParentVars[1]);
    tcc.showerParentReader->AddVariable("fMCSMom", &tcc.showerParentVars[2]);
    tcc.showerParentReader->AddVariable("fPfpLen", &tcc.showerParentVars[3]);
    tcc.showerParentReader->AddVariable("fSep", &tcc.showerParentVars[4]);
    tcc.showerParentReader->AddVariable("fDang1", &tcc.showerParentVars[5]);
    tcc.showerParentReader->AddVariable("fDang2", &tcc.showerParentVars[6]);
    tcc.showerParentReader->AddVariable("fChgFrac", &tcc.showerParentVars[7]);
    tcc.showerParentReader->AddVariable("fInShwrProb", &tcc.showerParentVars[8]);
    tcc.showerParentReader->BookMVA("BDT", fullFileSpec);
  } // ConfigureTMVA

  bool FindShowerStart(detinfo::DetectorPropertiesData const& detProp,
                       TCSlice& slc,
                       ShowerStruct3D& ss3,
                       bool prt)
  {
    // The shower ChgPos and Dir were found by the calling function but Dir
    // may be inconsistent with the 2D shower directions
    if (ss3.ID == 0) return false;

    if (prt) {
      mf::LogVerbatim myprt("TC");
      myprt << "Inside FSS: 3S" << ss3.ID << " ->";
      for (auto cid : ss3.CotIDs)
        myprt << " 2S" << cid;
      myprt << " Vx 3V" << ss3.Vx3ID;
    } // prt

    // find a parent Tj in the list of 2D showers that is the farthest away from the
    // shower center
    unsigned short useParentCID = 0;
    float maxParentSep = 0;
    unsigned short usePtSepCID = 0;
    float maxPtSep = 0;
    // assume that the 2D shower direction is consistent with the 3D shower direction. This
    // variable is only used when no parent exists
    bool dirOK = true;
    for (auto cid : ss3.CotIDs) {
      auto& ss = slc.cots[cid - 1];
      // Find the position, direction and projection in this plane
      auto& stj = slc.tjs[ss.ShowerTjID - 1];
      auto chgCtrTP = MakeBareTP(detProp, ss3.ChgPos, ss3.Dir, stj.CTP);
      // projection too small in this view?
      if (chgCtrTP.Delta < 0.5) continue;
      auto& startTP = stj.Pts[0];
      float sep = PosSep(startTP.Pos, chgCtrTP.Pos);
      if (ss.ParentID > 0) {
        if (sep > maxParentSep) {
          maxParentSep = sep;
          useParentCID = cid;
        }
      }
      else if (sep > maxPtSep) {
        // no parent exists.
        maxPtSep = sep;
        usePtSepCID = cid;
        float costh = DotProd(chgCtrTP.Dir, startTP.Dir);
        if (costh < 0) dirOK = false;
      }
    } // ci
    if (useParentCID == 0 && usePtSepCID == 0) return false;

    unsigned short useCID = useParentCID;
    if (useCID == 0) {
      useCID = usePtSepCID;
      if (!dirOK) ReverseShower("FSS", slc, useCID, prt);
    }

    // now define the start and length
    auto& ss = slc.cots[useCID - 1];
    auto& stj = slc.tjs[ss.ShowerTjID - 1];

    auto chgCtrTP = MakeBareTP(detProp, ss3.ChgPos, ss3.Dir, stj.CTP);
    if (ss3.Vx3ID > 0) {
      auto& vx3 = slc.vtx3s[ss3.Vx3ID - 1];
      ss3.Start[0] = vx3.X;
      ss3.Start[1] = vx3.Y;
      ss3.Start[2] = vx3.Z;
    }
    else {
      // no start vertex
      auto& startTP = stj.Pts[0];
      // The 2D separation btw the shower start and the shower center, converted
      // to the 3D separation
      float sep = tcc.wirePitch * PosSep(startTP.Pos, stj.Pts[1].Pos) / chgCtrTP.Delta;
      // set the start position
      for (unsigned short xyz = 0; xyz < 3; ++xyz)
        ss3.Start[xyz] = ss3.ChgPos[xyz] - sep * ss3.Dir[xyz];
    }
    // now do the end position
    auto& endTP = stj.Pts[2];
    float sep = tcc.wirePitch * PosSep(endTP.Pos, chgCtrTP.Pos) / chgCtrTP.Delta;
    for (unsigned short xyz = 0; xyz < 3; ++xyz)
      ss3.End[xyz] = ss3.ChgPos[xyz] + sep * ss3.Dir[xyz];
    ss3.Len = PosSep(ss3.Start, ss3.End);
    auto& startTP = stj.Pts[0];
    sep = PosSep(startTP.Pos, endTP.Pos);
    ss3.OpenAngle = (endTP.DeltaRMS - startTP.DeltaRMS) / sep;
    ss3.OpenAngle /= chgCtrTP.Delta;
    return true;

  } // FindShowerStart

  void Finish3DShowers(TCSlice& slc)
  {
    // Finish defining the showers, create a companion PFParticle for each one.
    // Note to the reader: This code doesn't use MakeVertexObsolete to kill vertices using the assumption
    // that Finish3DShowers is being called after reconstruction is complete, in which case there is no
    // need to re-calculate the 2D and 3D vertex score which could potentially screw up the decisions that have
    // already been made.

    // See if any need to be finished
    bool noShowers = true;
    for (auto& ss3 : slc.showers) {
      if (ss3.ID == 0) continue;
      noShowers = false;
    }
    if (noShowers) return;

    ChkAssns("Fin3D", slc);

    // create a pfp and define the mother-daughter relationship. At this point, the shower parent PFP (if
    // one exists) is a track-like pfp that might be the daughter of another pfp, e.g. the neutrino. This
    // association is changed from shower ParentID -> parent pfp, to shower PFP -> parent pfp
    for (auto& ss3 : slc.showers) {
      if (ss3.ID == 0) continue;
      if (ss3.PFPIndex != USHRT_MAX) continue;
      auto showerPFP = CreatePFP(slc);
      showerPFP.TjIDs.resize(ss3.CotIDs.size());
      for (unsigned short ii = 0; ii < ss3.CotIDs.size(); ++ii) {
        unsigned short cid = ss3.CotIDs[ii];
        if (cid == 0 || cid > slc.cots.size()) return;
        auto& ss = slc.cots[cid - 1];
        auto& stj = slc.tjs[ss.ShowerTjID - 1];
        showerPFP.TjIDs[ii] = stj.ID;
      } // ci
      showerPFP.PDGCode = 1111;
      auto& sf = showerPFP.SectionFits[0];
      sf.Pos = ss3.Start;
      sf.Dir = ss3.Dir;
      sf.DirErr = ss3.DirErr;
      showerPFP.Vx3ID[0] = ss3.Vx3ID;
      sf.Dir = ss3.Dir;
      // dEdx is indexed by plane for pfps and by 2D shower index for 3D showers
      for (auto cid : ss3.CotIDs) {
        auto& ss = slc.cots[cid - 1];
        unsigned short plane = DecodeCTP(ss.CTP).Plane;
        auto& stj = slc.tjs[ss.ShowerTjID - 1];
        showerPFP.dEdx[0][plane] = stj.dEdx[0];
        showerPFP.dEdxErr[0][plane] = 0.3 * stj.dEdx[0];
      } // ci
      ss3.PFPIndex = slc.pfps.size();
      if (ss3.ParentID > 0) {
        // see if this is a daughter
        auto& dtrPFP = slc.pfps[ss3.ParentID - 1];
        if (dtrPFP.ParentUID > 0) {
          // Transfer the daughter <-> parent assn
          auto slcIndx = GetSliceIndex("P", dtrPFP.ParentUID);
          auto& parPFP = slices[slcIndx.first].pfps[slcIndx.second];
          showerPFP.ParentUID = parPFP.UID;
          std::replace(parPFP.DtrUIDs.begin(), parPFP.DtrUIDs.end(), dtrPFP.UID, showerPFP.UID);
          dtrPFP.ParentUID = 0;
        } // dtrPFP.ParentID > 0
      }   // ss3.ParentID > 0
      slc.pfps.push_back(showerPFP);
    } // ss3

    // Transfer Tj hits from InShower Tjs to the shower Tj. This kills the InShower Tjs but doesn't consider how
    // this action affects vertices
    if (!TransferTjHits(slc, false)) return;

    // Associate shower Tj hits with 3D showers
    for (auto& ss3 : slc.showers) {
      if (ss3.ID == 0) continue;
      for (unsigned short ii = 0; ii < ss3.CotIDs.size(); ++ii) {
        unsigned short cid = ss3.CotIDs[ii];
        auto& ss = slc.cots[cid - 1];
        for (auto tjid : ss.TjIDs) {
          Trajectory& tj = slc.tjs[tjid - 1];
          auto tjHits = PutTrajHitsInVector(tj, kUsedHits);
          ss3.Hits.insert(ss3.Hits.end(), tjHits.begin(), tjHits.end());
          // kill vertices associated with the Tj unless it is the neutrino primary vtx
          for (unsigned short end = 0; end < 2; ++end) {
            if (tj.VtxID[end] == 0) continue;
            auto& vx2 = slc.vtxs[tj.VtxID[end] - 1];
            if (vx2.Vx3ID <= 0) {
              // This is a 2D vertex that is not matched in 3D. Kill it. Shouldn't need to
              // use MakeVertexObsolete here...
              vx2.ID = 0;
              continue;
            }
            // vx2 is matched in 3D. Kill it if it is NOT the neutrino primary
            auto& vx3 = slc.vtx3s[vx2.Vx3ID - 1];
            if (vx3.Neutrino) continue;
            vx3.ID = 0;
          } // end
        }   // tjid
      }     // ii
    }       // ss3

    // kill PFParticles
    if (!slc.pfps.empty()) {
      for (auto& pfp : slc.pfps) {
        if (pfp.ID == 0) continue;
        if (pfp.TjIDs.empty()) continue;
        unsigned short ndead = 0;
        for (auto tjid : pfp.TjIDs) {
          auto& tj = slc.tjs[tjid - 1];
          if (tj.AlgMod[kKilled]) ++ndead;
        } // tjid
        if (ndead == 0) continue;
        pfp.ID = 0;
      } // pfp
    }   // pfps not empty

    // kill orphan 2D vertices
    for (auto& vx2 : slc.vtxs) {
      if (vx2.ID == 0) continue;
      auto vxtjs = GetAssns(slc, "2V", vx2.ID, "T");
      if (vxtjs.empty()) vx2.ID = 0;
    } // vx2

    // kill orphan vertices
    for (auto& vx3 : slc.vtx3s) {
      if (vx3.ID == 0) continue;
      auto vxtjs = GetAssns(slc, "3V", vx3.ID, "T");
      if (vxtjs.empty()) {
        vx3.ID = 0;
        continue;
      }
    } // vx3

  } // Finish3DShowers

  bool FindShowers3D(detinfo::DetectorPropertiesData const& detProp, TCSlice& slc)
  {
    // Find 2D showers using 3D-matched trajectories. This returns true if showers were found
    // which requires re-doing the 3D trajectory match

    bool reconstruct = (tcc.showerTag[0] == 2) || (tcc.showerTag[0] == 4);
    if (!reconstruct) return false;

    bool prt2S = (tcc.dbgSlc && tcc.dbg2S);
    bool prt3S = (tcc.dbgSlc && tcc.dbg3S);

    std::string fcnLabel = "FS";

    geo::TPCGeo const& TPC = tcc.geom->TPC(slc.TPCID);
    // check for already-existing showers
    for (unsigned short plane = 0; plane < TPC.Nplanes(); ++plane) {
      CTP_t inCTP = EncodeCTP(slc.TPCID.Cryostat, slc.TPCID.TPC, plane);
      for (auto& ss : slc.cots)
        if (ss.CTP == inCTP) return false;
    }

    if (prt2S) {
      PrintPFPs("FSi", slc);
      PrintAllTraj(detProp, "FSi", slc, USHRT_MAX, 0);
    }

    // lists of Tj IDs in plane, (list1, list2, list3, ...)
    std::vector<std::vector<std::vector<int>>> bigList(slc.nPlanes);
    for (unsigned short plane = 0; plane < TPC.Nplanes(); ++plane) {
      std::vector<std::vector<int>> tjList;
      // Make lists of lists of ShowerLike tjs that will become showers
      //      FindCots(fcnLabel, slc, inCTP, tjList, prt2S);
      SaveTjInfo(slc, tjList, "TJL");
      if (tjList.empty()) continue;
      bigList[plane] = tjList;
    } // plane
    unsigned short nPlanesWithShowers = 0;
    for (unsigned short plane = 0; plane < TPC.Nplanes(); ++plane)
      if (!bigList.empty()) ++nPlanesWithShowers;
    if (nPlanesWithShowers < 2) return false;
    for (unsigned short plane = 0; plane < TPC.Nplanes(); ++plane) {
      CTP_t inCTP = EncodeCTP(slc.TPCID.Cryostat, slc.TPCID.TPC, plane);
      // print detailed debug info for one plane
      bool prtCTP = (prt2S && inCTP == debug.CTP);
      // Create a shower for each one
      for (auto& tjl : bigList[plane]) {
        if (tjl.empty()) continue;
        if (prtCTP) {
          mf::LogVerbatim myprt("TC");
          myprt << "Plane " << plane << " tjList";
          for (auto& tjID : tjl)
            myprt << " " << tjID;
        }
        auto ss = CreateSS(slc, tjl);
        if (ss.ID == 0) continue;
        if (!UpdateShower(fcnLabel, slc, ss, prtCTP)) continue;
        SaveTjInfo(slc, ss, "DS");
        FindNearbyTjs(fcnLabel, slc, ss, prtCTP);
        // don't try to do anything else here until all of the showers are defined
        if (!StoreShower(fcnLabel, slc, ss)) MakeShowerObsolete(fcnLabel, slc, ss, prtCTP);
      } // tjl
      ChkAssns(fcnLabel, slc);
      // try to merge showers in this plane using the lists of nearby Tjs
      if (inCTP == UINT_MAX) continue;
      if (slc.cots.empty()) continue;
      if (prtCTP) Print2DShowers("tjl", slc, inCTP, false);
      MergeShowerChain(fcnLabel, slc, inCTP, prtCTP);
      SaveAllCots(slc, inCTP, "MSC");
      if (prtCTP) Print2DShowers("MSCo", slc, inCTP, false);
      MergeOverlap(fcnLabel, slc, inCTP, prtCTP);
      SaveAllCots(slc, inCTP, "MO");
      if (prtCTP) Print2DShowers("MO", slc, inCTP, false);
      MergeNearby2DShowers(fcnLabel, slc, inCTP, prtCTP);
      SaveAllCots(slc, inCTP, "MSS");
      // merge sub-showers with other showers
      MergeSubShowers(fcnLabel, slc, inCTP, prtCTP);
      // merge sub-showers with shower-like tjs
      MergeSubShowersTj(fcnLabel, slc, inCTP, prtCTP);
      SaveAllCots(slc, inCTP, "MNrby");
      if (prtCTP) Print2DShowers("Nrby", slc, inCTP, false);
      bool tryMerge = false;
      for (unsigned short ii = 0; ii < slc.cots.size(); ++ii) {
        auto& ss = slc.cots[ii];
        if (ss.ID == 0) continue;
        if (ss.CTP != inCTP) continue;
        if (AddTjsInsideEnvelope(fcnLabel, slc, ss, prtCTP)) tryMerge = true;
        if (tcc.modes[kSaveShowerTree]) SaveAllCots(slc, inCTP, "Merge");
      }
      if (tryMerge) MergeNearby2DShowers(fcnLabel, slc, inCTP, prtCTP);
      SaveAllCots(slc, inCTP, "ATj2");
      if (prtCTP) Print2DShowers("ATIE", slc, inCTP, false);
    } // plane
    if (slc.cots.empty()) return false;
    if (prt3S) Print2DShowers("B4", slc, USHRT_MAX, false);
    // Match in 3D, make 3D showers and define them
    //    Match2DShowers(fcnLabel, slc, prt3S);
    SaveAllCots(slc, "M2DS");
    // Reconcile pfp and shower assns before the Parent search
    Reconcile3D(fcnLabel, slc, false, prt3S);
    SaveAllCots(slc, "R3D");
    for (auto& ss3 : slc.showers) {
      if (ss3.ID == 0) continue;
      FindParent(detProp, fcnLabel, slc, ss3, prt3S);
    } // ss3
    // Reconcile pfp and shower assns again
    Reconcile3D(fcnLabel, slc, true, prt3S);
    if (prt3S) Print2DShowers("M2DS", slc, USHRT_MAX, false);
    SaveAllCots(slc, "FP");

    // kill low energy 3D showers
    for (auto& ss3 : slc.showers) {
      if (ss3.ID == 0) continue;
      bool killMe = (ShowerEnergy(ss3) < tcc.showerTag[3]);
      if (killMe) MakeShowerObsolete(fcnLabel, slc, ss3, prt3S);
    } // ss3

    // kill 2D showers that are either below threshold or have only one tj
    for (auto& ss : slc.cots) {
      if (ss.ID == 0) continue;
      if (ss.SS3ID > 0) continue;
      bool killMe = (ss.TjIDs.size() == 1 || ss.Energy < tcc.showerTag[3]);
      // too small aspect ratio -> something track-like with some shower-like fuzz
      if (ss.AspectRatio < tcc.showerTag[10]) killMe = true;
      if (killMe) MakeShowerObsolete(fcnLabel, slc, ss, prt3S);
    } // ss

    unsigned short nNewShowers = 0;
    for (auto& ss : slc.cots) {
      if (ss.ID == 0) continue;
      if (ss.TjIDs.empty()) continue;
      SaveTjInfo(slc, ss, "Done");
      ++nNewShowers;
    } // ss

    return (nNewShowers > 0);

  } // FindShowers3D

  bool Reconcile3D(std::string inFcnLabel, TCSlice& slc, bool parentSearchDone, bool prt)
  {
    // Reconcile pfp and shower assns

    std::string fcnLabel = inFcnLabel + ".R3D2";

    if (prt) Print2DShowers("R3D2i", slc, USHRT_MAX, false);

    // consider them pair-wise
    if (slc.showers.size() > 1) {
      for (unsigned short ii = 0; ii < slc.showers.size() - 1; ++ii) {
        auto iss3 = slc.showers[ii];
        if (iss3.ID == 0) continue;
        auto iPInSS3 = GetAssns(slc, "3S", iss3.ID, "P");
        if (prt) {
          mf::LogVerbatim myprt("TC");
          myprt << fcnLabel << " 3S" << iss3.ID << " ->";
          for (auto pid : iPInSS3)
            myprt << " P" << pid;
        } // prt
        for (unsigned short jj = ii + 1; jj < slc.showers.size(); ++jj) {
          auto jss3 = slc.showers[jj];
          if (jss3.ID == 0) continue;
          auto jPInSS3 = GetAssns(slc, "3S", jss3.ID, "P");
          auto shared = SetIntersection(iPInSS3, jPInSS3);
          if (shared.empty()) continue;
          if (prt) {
            mf::LogVerbatim myprt("TC");
            myprt << fcnLabel << " Conflict i3S" << iss3.ID << " and j3S" << jss3.ID << " share";
            for (auto pid : shared)
              myprt << " P" << pid;
          } // prt
          // Compare the InShower likelihoods
          for (auto pid : shared) {
            auto& pfp = slc.pfps[pid - 1];
            float iProb = InShowerProb(slc, iss3, pfp);
            float jProb = InShowerProb(slc, jss3, pfp);
            if (prt)
              mf::LogVerbatim("TC")
                << fcnLabel << " i3S" << iss3.ID << " prob " << std::setprecision(3) << iProb
                << "  j3S" << jss3.ID << " prob " << jProb;
            if (iProb > jProb) {
              // remove the remnants of pfp from jss3
              RemovePFP(fcnLabel, slc, pfp, jss3, true, prt);
              // and add them to iss3
              AddPFP(fcnLabel, slc, pfp.ID, iss3, true, prt);
            }
            else {
              RemovePFP(fcnLabel, slc, pfp, iss3, true, prt);
              AddPFP(fcnLabel, slc, pfp.ID, jss3, true, prt);
            }
          } // pid
        }   // jj
      }     // ii
    }       // > 1 shower

    // Look for an in-shower pfp that is not the shower parent that is attached to a vertex.
    // Remove the attachment and any parent - daughter assn
    if (parentSearchDone) {
      for (auto& ss3 : slc.showers) {
        if (ss3.ID == 0) continue;
        auto PIn3S = GetAssns(slc, "3S", ss3.ID, "P");
        for (auto pid : PIn3S) {
          if (pid == ss3.ParentID) continue;
          auto& pfp = slc.pfps[pid - 1];
          for (unsigned short end = 0; end < 2; ++end) {
            if (pfp.Vx3ID[end] <= 0) continue;
            if (prt) {
              mf::LogVerbatim myprt("TC");
              myprt << fcnLabel << " Detach 3S" << ss3.ID << " -> P" << pfp.ID << "_" << end
                    << " -> 3V" << pfp.Vx3ID[end];
              if (pfp.ParentUID > 0) myprt << " ->Parent P" << pfp.ParentUID;
            }
            // remove P -> P parent-daughter assn
            pfp.Vx3ID[end] = 0;
            if (pfp.ParentUID > 0) {
              auto slcIndx = GetSliceIndex("P", pfp.ParentUID);
              auto& parentPFP = slices[slcIndx.first].pfps[slcIndx.second];
              std::vector<int> newDtrUIDs;
              for (auto did : parentPFP.DtrUIDs)
                if (did != pfp.UID) newDtrUIDs.push_back(did);
              parentPFP.DtrUIDs = newDtrUIDs;
            } // pfp Parent exists
          }   // end
        }     // pid
      }       // ss3
    }         // parentSearchDone

    // now look for 2D showers that not matched in 3D and have tjs
    // that are 3D-matched
    for (auto& ss : slc.cots) {
      if (ss.ID == 0) continue;
      if (ss.SS3ID > 0) continue;
      std::vector<int> matchedTjs;
      for (auto tid : ss.TjIDs)
        if (slc.tjs[tid - 1].AlgMod[kMat3D]) matchedTjs.push_back(tid);
      if (matchedTjs.empty()) continue;
      // try to merge it with an existing 3D-matched shower
      int mergeWith3S = 0;
      // The merge is compatible if it only matches to one shower
      bool isCompatible = true;
      for (auto tid : matchedTjs) {
        auto TInP = GetAssns(slc, "T", tid, "P");
        if (TInP.empty()) continue;
        // do some more checking. See what other showers the Tjs in the pfp
        // may belong to in other planes
        auto PIn3S = GetAssns(slc, "P", TInP[0], "3S");
        for (auto sid : PIn3S) {
          // require that the energy be lower
          auto& ss3 = slc.showers[sid - 1];
          if (ss.Energy > ShowerEnergy(ss3)) continue;
          if (mergeWith3S == 0) mergeWith3S = sid;
          if (mergeWith3S > 0 && mergeWith3S != sid) isCompatible = false;
        } // sid
      }   // tid
      if (prt) {
        mf::LogVerbatim myprt("TC");
        myprt << fcnLabel << " 2S" << ss.ID << " is not 3D-matched but has 3D-matched Tjs:";
        for (auto tid : matchedTjs) {
          myprt << " T" << tid;
          auto TInP = GetAssns(slc, "T", tid, "P");
          if (!TInP.empty()) { myprt << "->P" << TInP[0]; } // TInP not empty
        }                                                   // tid
      }                                                     // prt
      if (mergeWith3S == 0 && ss.Energy < 50) {
        // kill it
        MakeShowerObsolete(fcnLabel, slc, ss, prt);
      }
      else if (mergeWith3S > 0 && isCompatible) {
        auto& ss3 = slc.showers[mergeWith3S - 1];
        for (auto cid : ss3.CotIDs) {
          auto& oss = slc.cots[cid - 1];
          if (oss.CTP != ss.CTP) continue;
          if (!UpdateShower(fcnLabel, slc, ss3, prt)) return false;
          break;
        } // cid
      }   // mergeWith3S > 0
    }     // ss

    if (prt) Print2DShowers("R3D2o", slc, USHRT_MAX, false);

    ChkAssns(fcnLabel, slc);

    return true;
  } // Reconcile3D

  bool Reconcile3D(std::string inFcnLabel, TCSlice& slc, ShowerStruct3D& ss3, bool prt)
  {
    // checks consistency between pfparticles, showers and tjs associated with ss3
    if (ss3.ID == 0) return false;
    // it isn't a failure if there is a 3D shower in two planes
    if (ss3.CotIDs.size() < 3) return true;
    std::string fcnLabel = inFcnLabel + ".R3D";

    if (prt) Print2DShowers("R3Di", slc, USHRT_MAX, false);

    // make local copies so we can recover from a failure
    auto oldSS3 = ss3;
    std::vector<ShowerStruct> oldSS(ss3.CotIDs.size());
    for (unsigned short ii = 0; ii < ss3.CotIDs.size(); ++ii) {
      oldSS[ii] = slc.cots[ss3.CotIDs[ii] - 1];
    }

    std::vector<std::vector<int>> plist(ss3.CotIDs.size());
    for (unsigned short ci = 0; ci < ss3.CotIDs.size(); ++ci) {
      auto& ss = slc.cots[ss3.CotIDs[ci] - 1];
      for (auto tid : ss.TjIDs) {
        auto tToP = GetAssns(slc, "T", tid, "P");
        if (tToP.empty()) continue;
        // there should only be one pfp for a tj
        int pid = tToP[0];
        if (std::find(plist[ci].begin(), plist[ci].end(), pid) == plist[ci].end())
          plist[ci].push_back(pid);
      } // tid
    }   // ci
    // count the occurrence of each pfp
    std::vector<std::array<int, 2>> p_cnt;
    for (auto& pl : plist) {
      for (auto pid : pl) {
        unsigned short indx = 0;
        for (indx = 0; indx < p_cnt.size(); ++indx)
          if (p_cnt[indx][0] == pid) break;
        if (indx == p_cnt.size()) {
          // not found so add it
          p_cnt.push_back(std::array<int, 2>{{pid, 1}});
        }
        else {
          ++p_cnt[indx][1];
        }
      } // pid
    }   // pl
    if (prt) {
      mf::LogVerbatim myprt("TC");
      myprt << fcnLabel << " 3S" << ss3.ID << "\n";
      for (unsigned short ci = 0; ci < ss3.CotIDs.size(); ++ci) {
        myprt << " -> 2S" << ss3.CotIDs[ci] << " ->";
        for (auto pid : plist[ci])
          myprt << " P" << pid;
        myprt << "\n";
      } // ci
      myprt << " P<ID>_count:";
      for (auto& pc : p_cnt)
        myprt << " P" << pc[0] << "_" << pc[1];
    } // prt

    for (auto& pc : p_cnt) {
      // matched in all planes?
      if (pc[1] == (int)ss3.CotIDs.size()) continue;
      if (pc[1] == 2) {
        // missing a tj in a plane or is this a two-plane pfp?
        auto& pfp = slc.pfps[pc[0] - 1];
        if (pfp.TjIDs.size() > 2) {
          // ensure that none of the tjs in this pfp are included in a different shower
          auto PIn2S = GetAssns(slc, "P", pfp.ID, "2S");
          auto sDiff = SetDifference(PIn2S, ss3.CotIDs);
          if (!sDiff.empty() &&
              std::find(ss3.CotIDs.begin(), ss3.CotIDs.end(), sDiff[0]) == ss3.CotIDs.end())
            continue;
          if (prt) {
            mf::LogVerbatim myprt("TC");
            myprt << fcnLabel << " 3S" << ss3.ID << " P" << pfp.ID << " ->";
            for (auto sid : PIn2S)
              myprt << " 2S" << sid;
            myprt << " sDiff";
            for (auto sid : sDiff)
              myprt << " 2S" << sid;
          } // prt
          // missed a tj in a 2D shower so "add the PFP to the shower" and update it
          if (AddPFP(fcnLabel, slc, pfp.ID, ss3, true, prt)) {
            // Update the local copies
            oldSS3 = ss3;
            if (ss3.CotIDs.size() != oldSS.size()) return false;
            for (unsigned short ii = 0; ii < ss3.CotIDs.size(); ++ii)
              oldSS[ii] = slc.cots[ss3.CotIDs[ii] - 1];
          }
          else {
            // restore the previous state
            ss3 = oldSS3;
            for (unsigned short ii = 0; ii < oldSS.size(); ++ii) {
              auto& ss = oldSS[ii];
              slc.cots[ss.ID - 1] = ss;
            } // ii
          }   // AddPFP failed
        }     // pfp.TjIDs.size() > 2
      }
      else {
        // only one occurrence. check proximity to ss3
        auto& pfp = slc.pfps[pc[0] - 1];
        unsigned short nearEnd = 1 - FarEnd(pfp, ss3.ChgPos);
        float prob = InShowerProb(slc, ss3, pfp);
        auto pos = PosAtEnd(pfp, nearEnd);
        float sep = PosSep(pos, ss3.ChgPos);
        if (prt) {
          mf::LogVerbatim myprt("TC");
          myprt << fcnLabel << " one occurrence: P" << pfp.ID << "_" << nearEnd
                << " closest to ChgPos";
          myprt << " ChgPos " << std::fixed << std::setprecision(1) << ss3.ChgPos[0] << " "
                << ss3.ChgPos[1] << " " << ss3.ChgPos[2];
          myprt << " sep " << sep;
          myprt << " InShowerProb " << prob;
        } // prt
        if (sep < 30 && prob > 0.3 && AddPFP(fcnLabel, slc, pfp.ID, ss3, true, prt)) {
          if (prt) mf::LogVerbatim("TC") << " AddPFP success";
        }
        else if (!RemovePFP(fcnLabel, slc, pfp, ss3, true, prt)) {
          if (prt) mf::LogVerbatim("TC") << " RemovePFP failed";
        }
      } // only one occurrence.
    }   // pc

    if (!UpdateShower(fcnLabel, slc, ss3, prt)) return false;
    ChkAssns(fcnLabel, slc);
    if (prt) Print2DShowers("R3Do", slc, USHRT_MAX, false);

    return true;

  } // Reconcile3D

  void KillVerticesInShower(std::string inFcnLabel, TCSlice& slc, ShowerStruct& ss, bool prt)
  {
    // make the vertices inside the shower envelope obsolete and update dontCluster
    if (ss.ID == 0) return;
    if (!tcc.useAlg[kKillInShowerVx]) return;
    std::string fcnLabel = inFcnLabel + ".KVIS";

    for (auto& vx2 : slc.vtxs) {
      if (vx2.ID == 0) continue;
      if (vx2.CTP != ss.CTP) continue;
      // ensure it isn't associated with a neutrino vertex
      if (vx2.Vx3ID > 0 && slc.vtx3s[vx2.Vx3ID - 1].Neutrino) continue;
      if (!PointInsideEnvelope(vx2.Pos, ss.Envelope)) continue;
      if (prt)
        mf::LogVerbatim("TC") << fcnLabel << " Clobber 2V" << vx2.ID << " -> 3V" << vx2.Vx3ID
                              << " inside 2S" << ss.ID;
      // update dontCluster
      for (auto& dc : slc.dontCluster) {
        if (dc.TjIDs[0] == 0) continue;
        if (dc.Vx2ID != vx2.ID) continue;
        if (prt)
          mf::LogVerbatim("TC") << fcnLabel << " Remove T" << dc.TjIDs[0] << "-T" << dc.TjIDs[0]
                                << " in dontCluster";
        dc.TjIDs[0] = 0;
        dc.TjIDs[1] = 0;
      } // dc
      if (vx2.Vx3ID > 0) {
        auto TIn3V = GetAssns(slc, "3V", vx2.Vx3ID, "T");
        for (auto tid : TIn3V)
          slc.tjs[tid - 1].AlgMod[kKillInShowerVx] = true;
        auto& vx3 = slc.vtx3s[vx2.Vx3ID - 1];
        MakeVertexObsolete(slc, vx3);
      }
      else {
        auto TIn2V = GetAssns(slc, "2V", vx2.ID, "T");
        for (auto tid : TIn2V)
          slc.tjs[tid - 1].AlgMod[kKillInShowerVx] = true;
        MakeVertexObsolete("KVIS", slc, vx2, true);
      }
    } // vx2

  } // KillVerticesInShower

  bool CompleteIncompleteShower(std::string inFcnLabel, TCSlice& slc, ShowerStruct3D& ss3, bool prt)
  {
    // Find low-energy two-plane showers and try to complete it by making a 2D shower in the third
    // plane using 3D matched tjs

    if (slc.nPlanes != 3) return false;
    if (ss3.CotIDs.size() != 2) return false;

    if (!tcc.useAlg[kCompleteShower]) return false;

    std::string fcnLabel = inFcnLabel + ".CIS";
    if (prt) mf::LogVerbatim("TC") << fcnLabel << " 3S" << ss3.ID;

    auto& iss = slc.cots[ss3.CotIDs[0] - 1];
    auto& jss = slc.cots[ss3.CotIDs[1] - 1];
    // make a list of pfps for each SS
    std::vector<int> iplist;
    for (auto tid : iss.TjIDs) {
      auto plist = GetAssns(slc, "T", tid, "P");
      if (!plist.empty()) iplist.insert(iplist.end(), plist.begin(), plist.end());
    } // tid
    std::vector<int> jplist;
    for (auto tid : jss.TjIDs) {
      auto plist = GetAssns(slc, "T", tid, "P");
      if (!plist.empty()) jplist.insert(jplist.end(), plist.begin(), plist.end());
    } // tid
    // look for pfps that have tjs in both showers
    auto shared = SetIntersection(iplist, jplist);
    if (shared.empty()) return false;
    // put the list of tjs for both SS into a flat vector to simplify searching
    std::vector<int> flat = iss.TjIDs;
    flat.insert(flat.end(), jss.TjIDs.begin(), jss.TjIDs.end());
    // make a list of tjs in the k plane that maybe should made into a shower if they
    // aren't already in a shower that failed the 3D match
    std::vector<int> ktlist;
    for (auto pid : shared) {
      auto& pfp = slc.pfps[pid - 1];
      for (auto tid : pfp.TjIDs) {
        // ignore the tjs that are already in the shower in the other planes
        if (std::find(flat.begin(), flat.end(), tid) != flat.end()) continue;
        if (std::find(ktlist.begin(), ktlist.end(), tid) == ktlist.end()) ktlist.push_back(tid);
        // look for 2D vertices attached to this tj and add all attached tjs to ktlist
        auto& tj = slc.tjs[tid - 1];
        for (unsigned short end = 0; end < 2; ++end) {
          if (tj.VtxID[end] <= 0) continue;
          auto& vx2 = slc.vtxs[tj.VtxID[end] - 1];
          auto TIn2V = GetAssns(slc, "2V", vx2.ID, "T");
          for (auto vtid : TIn2V) {
            if (std::find(ktlist.begin(), ktlist.end(), vtid) == ktlist.end())
              ktlist.push_back(vtid);
          }
        } // end
      }   // tid
    }     // pid
    if (ktlist.empty()) return false;
    // list of 2D showers that include tjs in ktlist
    std::vector<int> ksslist;
    for (auto tid : ktlist) {
      auto& tj = slc.tjs[tid - 1];
      if (tj.SSID == 0) continue;
      // ignore showers that are 3D-matched. This case should be handled elsewhere by a merging function
      auto& ss = slc.cots[tj.SSID - 1];
      if (ss.SS3ID > 0) {
        if (prt)
          mf::LogVerbatim("TC") << fcnLabel << " Found existing T" << tid << " -> 2S" << ss.ID
                                << " -> 3S" << ss.SS3ID << " assn. Give up";
        return false;
      }
      if (std::find(ksslist.begin(), ksslist.end(), ss.ID) == ksslist.end())
        ksslist.push_back(ss.ID);
    } // tid
    // find the shower energy for this list
    float ktlistEnergy = ShowerEnergy(slc, ktlist);
    if (prt) {
      mf::LogVerbatim myprt("TC");
      myprt << fcnLabel << " 3S" << ss3.ID << "\n";
      myprt << " -> i2S" << iss.ID << " ->";
      for (auto pid : iplist)
        myprt << " P" << pid;
      myprt << "\n";
      myprt << " -> j2S" << jss.ID << " ->";
      for (auto pid : jplist)
        myprt << " P" << pid;
      myprt << "\n";
      geo::PlaneID iPlaneID = DecodeCTP(iss.CTP);
      geo::PlaneID jPlaneID = DecodeCTP(jss.CTP);
      unsigned short kplane = 3 - iPlaneID.Plane - jPlaneID.Plane;
      myprt << " kplane " << kplane << " ktlist:";
      for (auto tid : ktlist)
        myprt << " T" << tid;
      myprt << " ktlistEnergy " << ktlistEnergy;
      if (ksslist.empty()) { myprt << "\n No matching showers in kplane"; }
      else {
        myprt << "\n";
        myprt << " Candidate showers:";
        for (auto ssid : ksslist) {
          myprt << " 2S" << ssid;
          auto& sst = slc.cots[ssid - 1];
          if (sst.SS3ID > 0) myprt << "_3S" << sst.SS3ID;
        } // ssid
      }   // ssList not empty
    }     // prt
    if (ksslist.size() > 1) {
      if (prt)
        mf::LogVerbatim("TC") << fcnLabel
                              << " Found more than 1 shower. Need some better code here";
      return false;
    }
    if (ktlistEnergy > 2 * ShowerEnergy(ss3)) {
      if (prt)
        mf::LogVerbatim("TC") << fcnLabel
                              << " ktlistEnergy exceeds 2 * ss3 energy. Need some better code here";
      return false;
    } // ktlistEnergy too high

    if (ksslist.empty()) {
      // no 2D shower so make one using ktlist
      auto kss = CreateSS(slc, ktlist);
      if (kss.ID == 0) return false;
      kss.SS3ID = ss3.ID;
      if (prt)
        mf::LogVerbatim("TC") << fcnLabel << " 3S" << ss3.ID << " create new 2S" << kss.ID
                              << " from ktlist";
      if (!UpdateShower(fcnLabel, slc, kss, prt)) {
        if (prt) mf::LogVerbatim("TC") << fcnLabel << " UpdateShower failed 2S" << kss.ID;
        MakeShowerObsolete(fcnLabel, slc, kss, prt);
        return false;
      } // UpdateShower failed
      if (!StoreShower(fcnLabel, slc, kss)) {
        if (prt) mf::LogVerbatim("TC") << fcnLabel << " StoreShower failed";
        MakeShowerObsolete(fcnLabel, slc, kss, prt);
        return false;
      } // StoreShower failed
      ss3.CotIDs.push_back(kss.ID);
      auto& stj = slc.tjs[kss.ShowerTjID - 1];
      stj.AlgMod[kCompleteShower] = true;
      ss3.NeedsUpdate = true;
      return true;
    } // ksslist empty

    // associate ksslist[0] with 3S
    auto& ss = slc.cots[ksslist[0] - 1];
    if (prt)
      mf::LogVerbatim("TC") << fcnLabel << " 3S" << ss3.ID << " found pfp-matched 2S" << ss.ID;
    ss.SS3ID = ss3.ID;
    ss3.CotIDs.push_back(ss.ID);
    auto& stj = slc.tjs[ss.ShowerTjID - 1];
    stj.AlgMod[kCompleteShower] = true;
    ss3.NeedsUpdate = true;

    ChkAssns(fcnLabel, slc);
    return true;

  } // CompleteIncompleteShower

  bool UpdateShower(std::string inFcnLabel, TCSlice& slc, ShowerStruct& ss, bool prt)
  {
    // This is intended to be a single function replacement for FCC, FA, USWP, etc. The calling
    // function should have set NeedsUpdate true. A complete re-build is done if the ShPts vector
    // is empty. This is only required if a tj is removed from the shower. When adding a tj
    // to the shower the AddTj function appends the tj points to ShPts but doesn't fill
    // the ShPts RotPos values.
    // This function doesn't alter or check associations btw showers and tjs.

    if (ss.ID == 0) return false;
    if (ss.TjIDs.empty()) return false;
    if (ss.ShowerTjID <= 0 || ss.ShowerTjID > (int)slc.tjs.size()) return false;
    if (ss.ParentID > 0 && ss.ParentID > (int)slc.tjs.size()) return false;
    auto& stj = slc.tjs[ss.ShowerTjID - 1];
    if (stj.Pts.size() != 3) return false;

    std::string fcnLabel = inFcnLabel + ".U2S";

    if (!ss.NeedsUpdate && !ss.ShPts.empty()) return true;

    // initialize the variables that will be defined in this function
    ss.Energy = 0; // This is just ShowerEnergy(stj.TotChg) and could be deleted
    ss.AspectRatio = 10;
    // Direction FOM (0 = good). This is a property of the shower shape and is not
    // defined by the presence or absence of a parent tj start point
    ss.DirectionFOM = 10;
    // Total charge of all hits in the shower
    stj.TotChg = 0;
    for (auto& stp : stj.Pts) {
      // Shower start, charge center, and shower end
      stp.Pos = {{0.0, 0.0}};
      // Charge weighted average of hits this section (TP) along the shower
      stp.HitPos = {{0.0, 0.0}};
      // Direction from the start to the charge center - same for all TPs
      stp.Dir = {{0.0, 0.0}};
      // Hit charge in each section
      stp.Chg = 0;
      // transverse rms of hit positions relative to HitPos in this section
      stp.DeltaRMS = 0;
      // number of hits in this section
      stp.NTPsFit = 0;
    } // stp

    ss.ShPts.clear();
    for (auto tjid : ss.TjIDs) {
      if (tjid <= 0 || tjid > (int)slc.tjs.size()) return false;
      auto& tj = slc.tjs[tjid - 1];
      if (tj.CTP != ss.CTP) return false;
      if (tj.AlgMod[kShowerTj]) return false;
      for (unsigned short ipt = tj.EndPt[0]; ipt <= tj.EndPt[1]; ++ipt) {
        TrajPoint& tp = tj.Pts[ipt];
        for (unsigned short ii = 0; ii < tp.Hits.size(); ++ii) {
          if (!tp.UseHit[ii]) continue;
          unsigned int iht = tp.Hits[ii];
          auto& hit = (*evt.allHits)[slc.slHits[iht].allHitsIndex];
          if (hit.Integral() <= 0) continue;
          ShowerPoint shpt;
          shpt.HitIndex = iht;
          shpt.TID = tj.ID;
          shpt.Chg = hit.Integral();
          shpt.Pos[0] = hit.WireID().Wire;
          shpt.Pos[1] = hit.PeakTime() * tcc.unitsPerTick;
          ss.ShPts.push_back(shpt);
        } // ii
      }   // ipt
    }     // tjid
    if (prt) mf::LogVerbatim("TC") << fcnLabel << " 2S" << ss.ID << " nShPts " << ss.ShPts.size();

    if (ss.ShPts.size() < 3) return false;

    // find the charge center and total charge
    auto& stp1 = stj.Pts[1];
    for (auto& shpt : ss.ShPts) {
      stp1.Pos[0] += shpt.Chg * shpt.Pos[0];
      stp1.Pos[1] += shpt.Chg * shpt.Pos[1];
      stj.TotChg += shpt.Chg;
    } // shpt
    if (stj.TotChg <= 0) return false;
    stp1.Pos[0] /= stj.TotChg;
    stp1.Pos[1] /= stj.TotChg;
    ss.Energy = ChgToMeV(stj.TotChg);
    if (prt)
      mf::LogVerbatim("TC") << fcnLabel << " 2S" << ss.ID << " Chg ctr " << PrintPos(stp1.Pos)
                            << " Energy " << (int)ss.Energy << " MeV";

    // find the direction using the shower parent if one exists
    if (ss.ParentID > 0) {
      // Set the direction to be the start of the parent to the shower center
      auto& ptj = slc.tjs[ss.ParentID - 1];
      // find the parent end farthest away from the charge center
      unsigned short pend = FarEnd(ptj, stp1.Pos);
      auto& ptp = ptj.Pts[ptj.EndPt[pend]];
      stp1.Dir = PointDirection(ptp.Pos, stp1.Pos);
      stp1.Ang = atan2(stp1.Dir[1], stp1.Dir[0]);
    }
    else {
      // find the shower direction using the points
      double sum = 0.;
      double sumx = 0.;
      double sumy = 0.;
      double sumxy = 0.;
      double sumx2 = 0.;
      for (auto& shpt : ss.ShPts) {
        sum += shpt.Chg;
        double xx = shpt.Pos[0] - stp1.Pos[0];
        double yy = shpt.Pos[1] - stp1.Pos[1];
        sumx += shpt.Chg * xx;
        sumy += shpt.Chg * yy;
        sumxy += shpt.Chg * xx * yy;
        sumx2 += shpt.Chg * xx * xx;
      } // shpt
      double delta = sum * sumx2 - sumx * sumx;
      if (delta == 0) return false;
      // A is the intercept (This should be ~0 )
      //      double A = (sumx2 * sumy - sumx * sumxy) / delta;
      // B is the slope
      double B = (sumxy * sum - sumx * sumy) / delta;
      stp1.Ang = atan(B);
      stp1.Dir[0] = cos(stp1.Ang);
      stp1.Dir[1] = sin(stp1.Ang);
    } // no shower parent

    // TODO: ss.Angle should be eliminated. The shower tj Ang should be used instead
    ss.Angle = stp1.Ang;
    if (prt)
      mf::LogVerbatim("TC") << fcnLabel << " 2S" << ss.ID << " dir " << std::fixed
                            << std::setprecision(2) << stp1.Dir[0] << " " << stp1.Dir[1]
                            << " Angle " << stp1.Ang;
    for (unsigned short ipt = 0; ipt < 3; ++ipt) {
      if (ipt == 1) continue;
      stj.Pts[ipt].Dir = stp1.Dir;
      stj.Pts[ipt].Ang = stp1.Ang;
    } // ipt

    // fill the RotPos vector and sort
    std::vector<SortEntry> sortVec(ss.ShPts.size());
    unsigned short indx = 0;
    double cs = cos(-stp1.Ang);
    double sn = sin(-stp1.Ang);
    for (auto& shpt : ss.ShPts) {
      double xx = shpt.Pos[0] - stp1.Pos[0];
      double yy = shpt.Pos[1] - stp1.Pos[1];
      shpt.RotPos[0] = cs * xx - sn * yy;
      shpt.RotPos[1] = sn * xx + cs * yy;
      sortVec[indx].index = indx;
      sortVec[indx].val = shpt.RotPos[0];
      ++indx;
    } // shpt
    std::sort(sortVec.begin(), sortVec.end(), valsDecreasing);
    // put the points vector into the sorted order
    auto tPts = ss.ShPts;
    for (unsigned short ii = 0; ii < ss.ShPts.size(); ++ii)
      ss.ShPts[ii] = tPts[sortVec[ii].index];

    // Calculate the aspect ratio
    Point2_t alongTrans{{0.0, 0.0}};
    for (auto& shpt : ss.ShPts) {
      alongTrans[0] += shpt.Chg * std::abs(shpt.RotPos[0]);
      alongTrans[1] += shpt.Chg * std::abs(shpt.RotPos[1]);
    } // shpt
    alongTrans[0] /= stj.TotChg;
    alongTrans[1] /= stj.TotChg;
    if (alongTrans[1] == 0) return false;
    ss.AspectRatio = alongTrans[1] / alongTrans[0];
    if (prt)
      mf::LogVerbatim("TC") << fcnLabel << " 2S" << ss.ID << " AspectRatio " << ss.AspectRatio;

    // analyze the charge in three sections. Fill the stj HitPos and find DeltaRMS
    if (!AnalyzeRotPos(fcnLabel, slc, ss, prt)) return false;

    // Reverse the shower direction if needed and define the start point
    if (ss.ParentID > 0) {
      // The direction was defined by the start of a parent to the charge center. Check the consistency
      // with ShPts and reverse if needed
      auto& ptj = slc.tjs[ss.ParentID - 1];
      // find the parent end farthest away from the charge center
      unsigned short pend = FarEnd(ptj, stp1.Pos);
      auto& ptp = ptj.Pts[ptj.EndPt[pend]];
      auto& firstShPt = ss.ShPts[0];
      auto& lastShPt = ss.ShPts[ss.ShPts.size() - 1];
      if (PosSep2(ptp.Pos, lastShPt.Pos) < PosSep2(ptp.Pos, firstShPt.Pos))
        ReverseShower(fcnLabel, slc, ss, prt);
      stj.Pts[0].Pos = ptp.Pos;
    }
    else {
      // no parent exists. Compare the DeltaRMS at the ends
      if (stj.Pts[2].DeltaRMS < stj.Pts[0].DeltaRMS) ReverseShower(fcnLabel, slc, ss, prt);
      stj.Pts[0].Pos = ss.ShPts[0].Pos;
    } // no parent

    if (stj.Pts[2].DeltaRMS > 0) ss.DirectionFOM = stj.Pts[0].DeltaRMS / stj.Pts[2].DeltaRMS;
    // define the end point
    stj.Pts[2].Pos = ss.ShPts[ss.ShPts.size() - 1].Pos;

    DefineEnvelope(fcnLabel, slc, ss, prt);
    ss.NeedsUpdate = false;
    if (prt) mf::LogVerbatim("TC") << fcnLabel << " 2S" << ss.ID << " updated";
    return true;

  } // UpdateShower

  bool UpdateShower(std::string inFcnLabel, TCSlice& slc, ShowerStruct3D& ss3, bool prt)
  {
    // Updates the 3D shower presumably because the 2D showers were changed or need to be updated.
    // This function returns false if there was a failure.

    if (ss3.ID == 0) return false;
    if (ss3.CotIDs.size() < 2) return false;

    std::string fcnLabel = inFcnLabel + ".U3S";

    // see if any of the 2D showers need an update
    for (auto cid : ss3.CotIDs) {
      auto& ss = slc.cots[cid - 1];
      if (ss.NeedsUpdate && prt)
        std::cout << fcnLabel << " ********* 3S" << ss3.ID << " 2S" << ss.ID
                  << " needs an update...\n";
      UpdateShower(fcnLabel, slc, ss, prt);
    } // ci

    // check consistency
    if (ss3.ParentID > 0) {
      auto& pfp = slc.pfps[ss3.ParentID - 1];
      unsigned short pend = FarEnd(pfp, ss3.ChgPos);
      if (pfp.Vx3ID[pend] != ss3.Vx3ID) {
        if (prt)
          std::cout << fcnLabel << " ********* 3S" << ss3.ID << " has parent P" << ss3.ParentID
                    << " with a vertex that is not attached the shower\n";
      }
    } // ss3.ParentID > 0

    // Find the average position and direction using pairs of 2D shower Tjs
    std::array<Point3_t, 3> pos;
    // the direction of all points in 2D showers is the same
    Vector3_t dir;
    std::array<double, 3> chg;
    for (unsigned short ipt = 0; ipt < 3; ++ipt) {
      chg[ipt] = 0;
      for (unsigned short xyz = 0; xyz < 3; ++xyz) {
        pos[ipt][xyz] = 0;
        dir[xyz] = 0;
      }
    } // ipt
    unsigned short nok = 0;
    for (unsigned short ipt = 0; ipt < 3; ++ipt) {
      if (chg[ipt] == 0) continue;
      for (unsigned short xyz = 0; xyz < 3; ++xyz)
        pos[ipt][xyz] /= chg[ipt];
      SetMag(dir, 1);
      ++nok;
    } // ipt

    if (nok != 3) return false;
    ss3.ChgPos = pos[1];

    if (ss3.ParentID > 0) {
      // There is a 3D-matched pfp at the shower start. The end that is farthest away from the
      // shower center should be shower start
      auto& pfp = slc.pfps[ss3.ParentID - 1];
      unsigned short pend = FarEnd(pfp, ss3.ChgPos);
      ss3.Start = PosAtEnd(pfp, pend);
      ss3.Dir = dir;
    }
    else {
      ss3.Dir = dir;
      ss3.Start = pos[0];
    }
    // define the end
    ss3.End = pos[2];
    ss3.Len = PosSep(ss3.Start, ss3.End);

    // dE/dx, energy, etc
    for (auto cid : ss3.CotIDs) {
      auto& ss = slc.cots[cid - 1];
      auto& stj = slc.tjs[ss.ShowerTjID - 1];
      unsigned short plane = DecodeCTP(ss.CTP).Plane;
      ss3.Energy[plane] = ss.Energy;
      // TODO: calculate the errors in some better way
      ss3.EnergyErr[plane] = 0.3 * ss.Energy;
      // TODO: what does MIPEnergy mean anyway?
      ss3.MIPEnergy[plane] = ss3.EnergyErr[plane];
      ss3.MIPEnergyErr[plane] = ss.Energy;
      ss3.dEdx[plane] = stj.dEdx[0];
      ss3.dEdxErr[plane] = 0.3 * stj.dEdx[0];
    } // ci

    ss3.NeedsUpdate = false;
    if (prt) mf::LogVerbatim("TC") << fcnLabel << " 3S" << ss3.ID << " updated";
    return true;

  } // UpdateShower

  float Match3DFOM(detinfo::DetectorPropertiesData const& detProp,
                   std::string inFcnLabel,
                   TCSlice& slc,
                   ShowerStruct3D& ss3,
                   bool prt)
  {
    float fom = 0;
    float cnt = 0;
    for (unsigned short ii = 0; ii < ss3.CotIDs.size() - 1; ++ii) {
      unsigned short icid = ss3.CotIDs[ii];
      for (unsigned short jj = ii + 1; jj < ss3.CotIDs.size(); ++jj) {
        unsigned short jcid = ss3.CotIDs[jj];
        fom += Match3DFOM(detProp, inFcnLabel, slc, icid, jcid, prt);
        ++cnt;
      } // cj
    }   // ci
    if (cnt == 0) return 100;
    return fom / cnt;
  } // Match3DFOM

  float Match3DFOM(detinfo::DetectorPropertiesData const& detProp,
                   std::string inFcnLabel,
                   TCSlice& slc,
                   int icid,
                   int jcid,
                   int kcid,
                   bool prt)
  {
    if (icid == 0 || icid > (int)slc.cots.size()) return 100;
    if (jcid == 0 || jcid > (int)slc.cots.size()) return 100;
    if (kcid == 0 || kcid > (int)slc.cots.size()) return 100;

    float ijfom = Match3DFOM(detProp, inFcnLabel, slc, icid, jcid, prt);
    float jkfom = Match3DFOM(detProp, inFcnLabel, slc, jcid, kcid, prt);

    return 0.5 * (ijfom + jkfom);

  } // Match3DFOM

  float Match3DFOM(detinfo::DetectorPropertiesData const& detProp,
                   std::string inFcnLabel,
                   TCSlice& slc,
                   int icid,
                   int jcid,
                   bool prt)
  {
    // returns a Figure of Merit for a 3D match of two showers
    if (icid == 0 || icid > (int)slc.cots.size()) return 100;
    if (jcid == 0 || jcid > (int)slc.cots.size()) return 100;

    auto& iss = slc.cots[icid - 1];
    auto& istj = slc.tjs[iss.ShowerTjID - 1];
    auto& jss = slc.cots[jcid - 1];
    auto& jstj = slc.tjs[jss.ShowerTjID - 1];

    if (iss.CTP == jss.CTP) return 100;

    std::string fcnLabel = inFcnLabel + ".MFOM";

    float energyAsym = std::abs(iss.Energy - jss.Energy) / (iss.Energy + jss.Energy);

    // don't apply the asymmetry cut on low energy showers
    if ((iss.Energy > 200 || jss.Energy > 200) && energyAsym > 0.5) return 50;

    geo::PlaneID iPlnID = DecodeCTP(iss.CTP);
    geo::PlaneID jPlnID = DecodeCTP(jss.CTP);

    // compare match at the charge center
    float ix = detProp.ConvertTicksToX(istj.Pts[1].Pos[1] / tcc.unitsPerTick, iPlnID);
    float jx = detProp.ConvertTicksToX(jstj.Pts[1].Pos[1] / tcc.unitsPerTick, jPlnID);
    float pos1fom = std::abs(ix - jx) / 10;

    float mfom = energyAsym * pos1fom;

    if (prt) {
      mf::LogVerbatim myprt("TC");
      myprt << fcnLabel << " i2S" << iss.ID << " j2S" << jss.ID;
      myprt << std::fixed << std::setprecision(2);
      myprt << " pos1fom " << pos1fom;
      myprt << " energyAsym " << energyAsym;
      myprt << " mfom " << mfom;
    }

    return mfom;
  } // Madtch3DFOM

  void MergeTjList(std::vector<std::vector<int>>& tjList)
  {
    // Merge the lists of Tjs in the lists if they share a common Tj ID

    if (tjList.size() < 2) return;

    bool didMerge = true;
    while (didMerge) {
      didMerge = false;
      for (unsigned short itl = 0; itl < tjList.size() - 1; ++itl) {
        if (tjList[itl].empty()) continue;
        for (unsigned short jtl = itl + 1; jtl < tjList.size(); ++jtl) {
          if (tjList[itl].empty()) continue;
          auto& itList = tjList[itl];
          auto& jtList = tjList[jtl];
          // See if the j Tj is in the i tjList
          bool jtjInItjList = false;
          for (auto& jtj : jtList) {
            if (std::find(itList.begin(), itList.end(), jtj) != itList.end()) {
              jtjInItjList = true;
              break;
            }
            if (jtjInItjList) break;
          } // jtj
          if (jtjInItjList) {
            // append the jtList to itList
            itList.insert(itList.end(), jtList.begin(), jtList.end());
            // clear jtList
            jtList.clear();
            didMerge = true;
          }
        } // jtl
      }   // itl
    }     // didMerge

    // erase the deleted elements
    unsigned short imEmpty = 0;
    while (imEmpty < tjList.size()) {
      for (imEmpty = 0; imEmpty < tjList.size(); ++imEmpty)
        if (tjList[imEmpty].empty()) break;
      if (imEmpty < tjList.size()) tjList.erase(tjList.begin() + imEmpty);
    } // imEmpty < tjList.size()

    // sort the lists by increasing ID and remove duplicates
    for (auto& tjl : tjList) {
      std::sort(tjl.begin(), tjl.end());
      auto last = std::unique(tjl.begin(), tjl.end());
      tjl.erase(last, tjl.end());
    } // tjl

  } // MergeTjList

  bool RemovePFP(std::string inFcnLabel,
                 TCSlice& slc,
                 PFPStruct& pfp,
                 ShowerStruct3D& ss3,
                 bool doUpdate,
                 bool prt)
  {
    // removes the tjs in the pfp from the ss3 2D showers and optionally update. This function only returns
    // false if there was a failure. The absence of any pfp Tjs in ss3 is not considered a failure

    if (pfp.ID == 0 || ss3.ID == 0) return false;

    std::string fcnLabel = inFcnLabel + ".RemP";
    for (auto tid : pfp.TjIDs) {
      for (auto cid : ss3.CotIDs) {
        auto& ss = slc.cots[cid - 1];
        if (std::find(ss.TjIDs.begin(), ss.TjIDs.end(), tid) == ss.TjIDs.end()) continue;
        if (!RemoveTj(fcnLabel, slc, tid, ss, doUpdate, prt)) return false;
        ss3.NeedsUpdate = true;
      } // cid
    }   // ptid

    if (doUpdate && ss3.NeedsUpdate) UpdateShower(fcnLabel, slc, ss3, prt);
    return true;

  } // Remove PFP

  bool AddPFP(std::string inFcnLabel,
              TCSlice& slc,
              int pID,
              ShowerStruct3D& ss3,
              bool doUpdate,
              bool prt)
  {
    // Add the tjs in the pfp with id = pID to the 2D showers in ss3 and optionally update everything. This
    // function returns true if the addition was successful or if the Tjs in the pfp are already in ss3.
    // This function returns false if there was a failure. There isn't any error recovery.

    std::string fcnLabel = inFcnLabel + ".AddP";

    if (pID <= 0 || pID > (int)slc.pfps.size()) return false;
    auto& pfp = slc.pfps[pID - 1];

    if (pfp.TPCID != ss3.TPCID) {
      mf::LogVerbatim("TC") << fcnLabel << " P" << pID << " is in the wrong TPC for 3S" << ss3.ID;
      return false;
    }

    for (auto tid : pfp.TjIDs) {
      auto& tj = slc.tjs[tid - 1];
      // is this tj in a 2D shower that is in a 3D shower that is not this shower?
      if (tj.SSID > 0) {
        auto& ss = slc.cots[tj.SSID - 1];
        if (ss.SS3ID > 0 && ss.SS3ID != ss3.ID) {
          if (prt)
            mf::LogVerbatim("TC") << fcnLabel << " Conflict: 3S" << ss3.ID << " adding P" << pfp.ID
                                  << " -> T" << tid << " is in 2S" << tj.SSID << " that is in 3S"
                                  << ss.SS3ID << " that is not this shower";
          return false;
        } // conflict
        // tj is in the correct 2D shower so nothing needs to be done
        if (prt)
          mf::LogVerbatim("TC") << fcnLabel << " 3S" << ss3.ID << " adding P" << pfp.ID << " -> T"
                                << tid << " is in the correct shower 2S" << tj.SSID;
        continue;
      } // pfp tj is in a shower
      if (prt) {
        mf::LogVerbatim myprt("TC");
        myprt << fcnLabel << " 3S" << ss3.ID << " adding P" << pfp.ID << " -> T" << tid;
        myprt << " tj.SSID 2S" << tj.SSID;
      } // prt
      // add it to the shower in the correct CTP
      for (auto& cid : ss3.CotIDs) {
        auto& ss = slc.cots[cid - 1];
        if (ss.CTP != tj.CTP) continue;
        // Add it to the shower.
        AddTj(fcnLabel, slc, tid, ss, doUpdate, prt);
        ss3.NeedsUpdate = true;
        break;
      } // cid
    }   // tid

    if (doUpdate && ss3.NeedsUpdate) UpdateShower(fcnLabel, slc, ss3, prt);
    return true;

  } // AddPFP

  bool AddTj(std::string inFcnLabel,
             TCSlice& slc,
             int tjID,
             ShowerStruct& ss,
             bool doUpdate,
             bool prt)
  {
    // Adds the Tj to the shower and optionally updates the shower variables

    if (tjID <= 0 || tjID > (int)slc.tjs.size()) return false;

    std::string fcnLabel = inFcnLabel + ".AddT";

    Trajectory& tj = slc.tjs[tjID - 1];

    if (tj.CTP != ss.CTP) {
      mf::LogVerbatim("TC") << fcnLabel << " T" << tjID << " is in the wrong CTP for 2S" << ss.ID;
      return false;
    }

    if (tj.SSID > 0) {
      if (tj.SSID == ss.ID) {
        if (prt) mf::LogVerbatim("TC") << fcnLabel << " T" << tjID << " is already in 2S" << ss.ID;
        return true;
      }
      else {
        if (prt)
          mf::LogVerbatim("TC") << fcnLabel << " Can't add T" << tjID << " to 2S" << ss.ID
                                << ". it is already used in 2S" << tj.SSID;
        return false;
      }
    } // tj.SSID > 0

    ss.TjIDs.push_back(tjID);
    tj.SSID = ss.ID;
    std::sort(ss.TjIDs.begin(), ss.TjIDs.end());
    // remove this ID from the NearTjIDs list
    for (unsigned short ii = 0; ii < ss.NearTjIDs.size(); ++ii) {
      if (ss.NearTjIDs[ii] == tjID) ss.NearTjIDs.erase(ss.NearTjIDs.begin() + ii);
    }
    // count the hits in the TPs
    unsigned short cnt = 0;
    for (unsigned short ipt = tj.EndPt[0]; ipt <= tj.EndPt[1]; ++ipt) {
      TrajPoint& tp = tj.Pts[ipt];
      if (tp.Chg == 0) continue;
      for (unsigned short ii = 0; ii < tp.Hits.size(); ++ii)
        if (tp.UseHit[ii]) ++cnt;
    } // ipt
    unsigned short newSize = ss.ShPts.size() + cnt;
    cnt = ss.ShPts.size();
    ss.ShPts.resize(newSize);
    // now add them
    for (unsigned short ipt = tj.EndPt[0]; ipt <= tj.EndPt[1]; ++ipt) {
      TrajPoint& tp = tj.Pts[ipt];
      if (tp.Chg == 0) continue;
      for (unsigned short ii = 0; ii < tp.Hits.size(); ++ii) {
        if (tp.UseHit[ii]) {
          unsigned int iht = tp.Hits[ii];
          ss.ShPts[cnt].HitIndex = iht;
          ss.ShPts[cnt].TID = tj.ID;
          auto& hit = (*evt.allHits)[slc.slHits[iht].allHitsIndex];
          ss.ShPts[cnt].Chg = hit.Integral();
          ss.ShPts[cnt].Pos[0] = hit.WireID().Wire;
          ss.ShPts[cnt].Pos[1] = hit.PeakTime() * tcc.unitsPerTick;
          ++cnt;
        }
      }
    } // ipt
    if (prt) mf::LogVerbatim("TC") << fcnLabel << " Added T" << tj.ID << " to 2S" << ss.ID;
    ss.NeedsUpdate = true;

    if (doUpdate) return UpdateShower(fcnLabel, slc, ss, prt);
    return true;

  } // AddTj

  bool RemoveTj(std::string inFcnLabel,
                TCSlice& slc,
                int TjID,
                ShowerStruct& ss,
                bool doUpdate,
                bool prt)
  {
    // Removes the Tj from a shower

    if (TjID > (int)slc.tjs.size()) return false;

    std::string fcnLabel = inFcnLabel + ".RTj";

    // make sure it isn't already in a shower
    Trajectory& tj = slc.tjs[TjID - 1];

    if (tj.SSID != ss.ID) {
      if (prt)
        mf::LogVerbatim("TC") << fcnLabel << " Can't Remove T" << TjID << " from 2S" << ss.ID
                              << " because it's not in this shower";
      // This isn't a failure
      return true;
    }
    tj.AlgMod[kShwrParent] = false;

    bool gotit = false;
    for (unsigned short ii = 0; ii < ss.TjIDs.size(); ++ii) {
      if (TjID == ss.TjIDs[ii]) {
        ss.TjIDs.erase(ss.TjIDs.begin() + ii);
        gotit = true;
        break;
      }
    } // ii
    if (!gotit) return false;
    tj.SSID = 0;
    // Removing a parent Tj?
    if (TjID == ss.ParentID) ss.ParentID = 0;
    // re-build everything?
    if (prt) mf::LogVerbatim("TC") << fcnLabel << " Remove T" << TjID << " from 2S" << ss.ID;
    // removed the only tj
    if (ss.TjIDs.empty()) {
      if (prt) mf::LogVerbatim("TC") << fcnLabel << " Removed the last Tj. Killing 2S" << ss.ID;
      MakeShowerObsolete(fcnLabel, slc, ss, prt);
      return true;
    }
    // clear out the shower points to force a complete update when UpdateShower is next called
    ss.ShPts.clear();
    if (doUpdate) {
      ss.NeedsUpdate = true;
      return UpdateShower(fcnLabel, slc, ss, prt);
    }
    return true;
  } // RemoveTj

  bool FindParent(detinfo::DetectorPropertiesData const& detProp,
                  std::string inFcnLabel,
                  TCSlice& slc,
                  ShowerStruct3D& ss3,
                  bool prt)
  {
    // look for a parent pfp for the shower.The 2D showers associated with it
    // The parent should be at the start of the shower (shend = 0) if it is well-defined
    // (has small AspectRatio and small DirectionFOM). A search is also made for a parent at
    // the "wrong" end of the shower (shend = 1). The best one at the wrong end is used if
    // no parent is found at the shower start and the shower is poorly defined.
    //
    // This function returns false if there was a failure. Not finding a parent is not a failure

    if (ss3.ID == 0) return false;
    if (ss3.CotIDs.size() < 2) return false;
    // Use the MVA reader
    if (!tcc.showerParentReader) return false;
    if (tcc.showerParentVars.size() != 9) return false;
    if (!tcc.useAlg[kShwrParent]) return false;

    std::string fcnLabel = inFcnLabel + ".FPar";
    int truPFP = 0;

    double energy = ShowerEnergy(ss3);
    // the energy is probably under-estimated since there isn't a parent yet.
    energy *= 1.2;
    double shMaxAlong, along95;
    ShowerParams(energy, shMaxAlong, along95);
    if (prt)
      mf::LogVerbatim("TC") << fcnLabel << " 3S" << ss3.ID << " Estimated energy " << (int)energy
                            << " MeV shMaxAlong " << shMaxAlong << " along95 " << along95
                            << " truPFP " << truPFP;

    // look for the pfp that has a reasonable probability of being in the shower but with the
    // minimum along distance from the shower center.
    // This image explains the concept. The *'s represents the points in 2D showers that define
    // the charge center in 3D, ChgPos. We are looking for a pfp parent denoted by ----. The end
    // that is farthest from ChgPos is labeled P (pfp.XYZ[pend] in the code). The expected distance
    // from the shower start to shower Max, shMaxAlong, is found from ShowerParams. The longitudinal
    // and transverse distance of P relative to the shower center is alongTrans. The first cut on a
    // candidate parent is made requiring that D (alongTrans[0]) > 0.5 * shMaxAlong.
    //
    //       __________shend = 0________________      __________shend = 1________________
    //                                **********
    //                    ******  ******                   ******  ******
    //       P-----*****ChgPos******   **                *****ChgPos******-------P
    //                     ********     *******              *******
    //                     |----> along                          |---> along
    //       |<----D------>|                                     |<----D------>|
    // |<----shMaxAlong--->|                                     |<----shMaxAlong--->|
    //
    // Candidate parent ID for each end and the FOM
    std::array<int, 2> parID{{0, 0}};
    std::array<float, 2> parFOM{{-1E6, -1E6}};

    // temp vector to flag pfps that are already parents - indexed by ID
    std::vector<bool> isParent(slc.pfps.size() + 1, false);
    for (auto& oldSS3 : slc.showers) {
      if (oldSS3.ID == 0) continue;
      isParent[oldSS3.ParentID] = true;
    } // pfp

    // put the tjs associated with this shower in a flat vector
    auto TjsInSS3 = GetAssns(slc, "3S", ss3.ID, "T");
    if (TjsInSS3.empty()) return false;

    for (auto& pfp : slc.pfps) {
      if (pfp.ID == 0) continue;
      bool dprt = (pfp.ID == truPFP);
      if (pfp.TPCID != ss3.TPCID) continue;
      // ignore neutrinos
      if (pfp.PDGCode == 14 || pfp.PDGCode == 14) continue;
      // ignore shower pfps
      if (pfp.PDGCode == 1111) continue;
      // ignore existing parents
      if (isParent[pfp.ID]) continue;
      // check for inconsistent pfp - shower tjs
      if (DontCluster(slc, pfp.TjIDs, TjsInSS3)) continue;
      // ignore if the pfp energy is larger than the shower energy
      float pfpEnergy = 0;
      float minEnergy = 1E6;
      for (auto tid : pfp.TjIDs) {
        auto& tj = slc.tjs[tid - 1];
        float energy = ChgToMeV(tj.TotChg);
        pfpEnergy += energy;
        if (energy < minEnergy) minEnergy = energy;
      }
      pfpEnergy -= minEnergy;
      pfpEnergy /= (float)(pfp.TjIDs.size() - 1);
      if (dprt)
        mf::LogVerbatim("TC") << fcnLabel << " 3S" << ss3.ID << " P" << pfp.ID << " E "
                              << pfpEnergy;
      if (pfpEnergy > energy) continue;
      // find the end that is farthest away
      unsigned short pEnd = FarEnd(pfp, ss3.ChgPos);
      auto pos = PosAtEnd(pfp, pEnd);
      auto pToS = PointDirection(pos, ss3.ChgPos);
      double costh1 = std::abs(DotProd(pToS, ss3.Dir));
      if (costh1 < 0.4) continue;
      auto dir = DirAtEnd(pfp, pEnd);
      float costh2 = DotProd(pToS, dir);
      // distance^2 between the pfp end and the shower start, charge center, and shower end
      float distToStart2 = PosSep2(pos, ss3.Start);
      float distToChgPos2 = PosSep2(pos, ss3.ChgPos);
      float distToEnd2 = PosSep2(pos, ss3.End);
      if (dprt)
        mf::LogVerbatim("TC") << fcnLabel << " 3S" << ss3.ID << " P" << pfp.ID << "_" << pEnd
                              << " distToStart " << sqrt(distToStart2) << " distToChgPos "
                              << sqrt(distToChgPos2) << " distToEnd " << sqrt(distToEnd2);
      // find the end of the shower closest to the pfp
      unsigned short shEnd = 0;
      if (distToEnd2 < distToStart2) shEnd = 1;
      // This can't be a parent if the pfp end is closer to the shower center than the start or the end
      if (shEnd == 0 && distToChgPos2 < distToStart2) continue;
      if (shEnd == 1 && distToChgPos2 < distToEnd2) continue;
      if (dprt)
        mf::LogVerbatim("TC") << fcnLabel << " 3S" << ss3.ID << "_" << shEnd << " P" << pfp.ID
                              << "_" << pEnd << " costh1 " << costh1;
      Point2_t alongTrans;
      // find the longitudinal and transverse components of the pfp start point relative to the
      // shower center
      FindAlongTrans(ss3.ChgPos, ss3.Dir, pos, alongTrans);
      if (dprt)
        mf::LogVerbatim("TC") << fcnLabel << "   alongTrans " << alongTrans[0] << " "
                              << alongTrans[1];
      // find the probability this point is inside the shower. Offset by the expected
      // shower max distance. distToShowerMax will be > 0 if the pfp end is closer to
      // ChgPos than expected from the parameterization
      float distToShowerMax = shMaxAlong - std::abs(alongTrans[0]);
      float prob = InShowerProbLong(energy, distToShowerMax);
      if (dprt) mf::LogVerbatim("TC") << fcnLabel << "        prob " << prob;
      if (prob < 0.1) continue;
      float chgFrac = 0;
      float totSep = 0;
      // find the charge fraction btw the pfp start and the point that is
      // half the distance to the charge center in each plane
      for (unsigned short plane = 0; plane < slc.nPlanes; ++plane) {
        CTP_t inCTP = EncodeCTP(ss3.TPCID.Cryostat, ss3.TPCID.TPC, plane);
        int ssid = 0;
        for (auto cid : ss3.CotIDs) {
          auto& ss = slc.cots[cid - 1];
          if (ss.CTP != inCTP) continue;
          ssid = ss.ID;
          break;
        } // cid
        if (ssid == 0) continue;
        auto tpFrom = MakeBareTP(detProp, pos, pToS, inCTP);
        auto& ss = slc.cots[ssid - 1];
        auto& stp1 = slc.tjs[ss.ShowerTjID - 1].Pts[1];
        float sep = PosSep(tpFrom.Pos, stp1.Pos);
        float toPos = tpFrom.Pos[0] + 0.5 * tpFrom.Dir[0] * sep;
        float cf = ChgFracBetween(tpFrom, toPos);
        // weight by the separation in the plane
        totSep += sep;
        chgFrac += sep * cf;
      } // plane
      if (totSep > 0) chgFrac /= totSep;
      // load the MVA variables
      tcc.showerParentVars[0] = energy;
      tcc.showerParentVars[1] = pfpEnergy;
      tcc.showerParentVars[2] = MCSMom(slc, pfp.TjIDs);
      auto startPos = PosAtEnd(pfp, 0);
      auto endPos = PosAtEnd(pfp, 1);
      tcc.showerParentVars[3] = PosSep(startPos, endPos);
      tcc.showerParentVars[4] = sqrt(distToChgPos2);
      tcc.showerParentVars[5] = acos(costh1);
      tcc.showerParentVars[6] = acos(costh2);
      tcc.showerParentVars[7] = chgFrac;
      tcc.showerParentVars[8] = prob;
      float candParFOM = tcc.showerParentReader->EvaluateMVA("BDT");

      if (prt) {
        mf::LogVerbatim myprt("TC");
        myprt << fcnLabel;
        myprt << " 3S" << ss3.ID << "_" << shEnd;
        myprt << " P" << pfp.ID << "_" << pEnd << " ParentVars";
        for (auto var : tcc.showerParentVars)
          myprt << " " << std::fixed << std::setprecision(2) << var;
        myprt << " candParFOM " << candParFOM;
      } // prt
      if (candParFOM > parFOM[shEnd]) {
        parFOM[shEnd] = candParFOM;
        parID[shEnd] = pfp.ID;
      }
    } // pfp

    if (parID[0] == 0 && parID[1] == 0) return true;

    // decide which to use
    int bestPFP = 0;
    // find the average DirectionFOM to help decide
    float aveDirFOM = 0;
    float fom3D = 0;
    for (auto cid : ss3.CotIDs)
      aveDirFOM += slc.cots[cid - 1].DirectionFOM;
    aveDirFOM /= (float)ss3.CotIDs.size();
    if (prt) {
      mf::LogVerbatim("TC") << fcnLabel << " 3S" << ss3.ID << " parID[0] " << parID[0] << " fom "
                            << parFOM[0] << " parID[1] " << parID[1] << " fom " << parFOM[1]
                            << " aveDirFOM " << aveDirFOM;
    }
    if (parID[0] > 0 && parID[1] > 0 && aveDirFOM > 0.3) {
      // candidates at both ends and the direction is not well known. Take
      // the one with the best FOM
      bestPFP = parID[0];
      fom3D = parFOM[0];
      if (parFOM[1] > parFOM[0]) {
        bestPFP = parID[1];
        fom3D = parFOM[1];
      }
    }
    else if (parID[0] > 0) {
      bestPFP = parID[0];
      fom3D = parFOM[0];
    }
    else {
      bestPFP = parID[1];
      fom3D = parFOM[1];
    }
    if (bestPFP == 0) return true;

    if (prt)
      mf::LogVerbatim("TC") << fcnLabel << " 3S" << ss3.ID << " setting P" << bestPFP
                            << " as the parent " << fom3D;

    // make local copies so we can recover from a failure
    auto oldSS3 = ss3;
    std::vector<ShowerStruct> oldSS(ss3.CotIDs.size());
    for (unsigned short ii = 0; ii < ss3.CotIDs.size(); ++ii) {
      oldSS[ii] = slc.cots[ss3.CotIDs[ii] - 1];
    }

    ss3.ParentID = bestPFP;
    auto& pfp = slc.pfps[bestPFP - 1];
    unsigned short pend = FarEnd(pfp, ss3.ChgPos);
    ss3.Vx3ID = pfp.Vx3ID[pend];

    if (SetParent(detProp, fcnLabel, slc, pfp, ss3, prt) && UpdateShower(fcnLabel, slc, ss3, prt)) {
      if (prt) mf::LogVerbatim("TC") << fcnLabel << " 3S" << ss3.ID << " successful update";
      return true;
    }

    if (prt) mf::LogVerbatim("TC") << fcnLabel << " 3S" << ss3.ID << " Failed. Recovering...";
    ss3 = oldSS3;
    for (unsigned short ii = 0; ii < oldSS.size(); ++ii) {
      auto& ss = oldSS[ii];
      slc.cots[ss.ID - 1] = ss;
    } // ii
    return false;

  } // FindParent

  bool SetParent(detinfo::DetectorPropertiesData const& detProp,
                 std::string inFcnLabel,
                 TCSlice& slc,
                 PFPStruct& pfp,
                 ShowerStruct3D& ss3,
                 bool prt)
  {
    // set the pfp as the parent of ss3. The calling function should do the error recovery
    if (pfp.ID == 0 || ss3.ID == 0) return false;
    if (ss3.CotIDs.empty()) return false;

    std::string fcnLabel = inFcnLabel + ".SP";

    for (auto cid : ss3.CotIDs) {
      auto& ss = slc.cots[cid - 1];
      auto& stj = slc.tjs[ss.ShowerTjID - 1];
      stj.VtxID[0] = 0;
      if (ss.ParentID > 0) {
        auto& oldParent = slc.tjs[ss.ParentID - 1];
        oldParent.AlgMod[kShwrParent] = false;
        ss.ParentID = 0;
        ss.ParentFOM = 10;
      } // remove old parents
      // add new parents
      for (auto tjid : pfp.TjIDs) {
        auto& tj = slc.tjs[tjid - 1];
        if (tj.CTP != ss.CTP) continue;
        if (std::find(ss.TjIDs.begin(), ss.TjIDs.end(), tjid) == ss.TjIDs.end()) {
          // Add the tj but don't update yet
          if (!AddTj(fcnLabel, slc, tjid, ss, false, prt)) return false;
        } // parent not in ss
        // Don't define it to be the parent if it is short and the pfp projection in this plane is low
        auto pos = PosAtEnd(pfp, 0);
        auto dir = DirAtEnd(pfp, 0);
        auto tp = MakeBareTP(detProp, pos, dir, tj.CTP);
        unsigned short npts = tj.EndPt[1] - tj.EndPt[0] + 1;
        if (tp.Delta > 0.5 || npts > 20) {
          if (prt)
            mf::LogVerbatim("TC") << fcnLabel << " 3S" << ss3.ID << " parent P" << pfp.ID << " -> T"
                                  << tjid << " -> 2S" << ss.ID << " parent";
        }
        else {
          if (prt)
            mf::LogVerbatim("TC") << fcnLabel << " 3S" << ss3.ID << " parent P" << pfp.ID << " -> T"
                                  << tjid << " low projection in plane " << tp.Delta
                                  << ". Not a parent";
          continue;
        }
        ss.ParentID = tjid;
        ss.NeedsUpdate = true;
        // set the ss start vertex
        if (ss3.Vx3ID > 0) {
          auto& vx3 = slc.vtx3s[ss3.Vx3ID - 1];
          auto v2list = GetAssns(slc, "3V", vx3.ID, "2V");
          for (unsigned short end = 0; end < 2; ++end) {
            if (tj.VtxID[end] <= 0) continue;
            if (std::find(v2list.begin(), v2list.end(), tj.VtxID[end]) != v2list.end())
              stj.VtxID[0] = tj.VtxID[end];
          } // end
        }   // ss3.Vx3ID > 0
        // and update
        if (!UpdateShower(fcnLabel, slc, ss, prt)) return false;
      } // tjid
    }   // cid
    ss3.ParentID = pfp.ID;

    unsigned short pEnd = FarEnd(pfp, ss3.ChgPos);
    ss3.Vx3ID = pfp.Vx3ID[pEnd];
    float fom3D = ParentFOM(fcnLabel, slc, pfp, ss3, prt);
    for (auto cid : ss3.CotIDs)
      slc.cots[cid - 1].ParentFOM = fom3D;

    return true;
  } // SetParent

  bool IsShowerLike(TCSlice const& slc, std::vector<int> const& TjIDs)
  {
    // Vote for the list of Tjs (assumed associated with a PFParticle) being shower-like
    if (TjIDs.empty()) return false;
    unsigned short cnt = 0;
    for (auto tid : TjIDs) {
      if (tid <= 0 || tid > (int)slc.tjs.size()) continue;
      if (slc.tjs[tid - 1].AlgMod[kShowerLike] > 0) ++cnt;
    } // tjid
    return (cnt > 1);
  } // IsInShower

  void ShowerParams(double showerEnergy, double& shMaxAlong, double& along95)
  {
    // Returns summary properties of photon showers parameterized in the energy range 50 MeV < E_gamma < 1 GeV:
    // shMaxAlong = the longitudinal distance (cm) between the start of the shower and the center of charge
    // along95 = the longitudinal distance (cm) between the start of the shower and 95% energy containment
    // all units are in cm
    if (showerEnergy < 10) {
      shMaxAlong = 0;
      along95 = 0;
      return;
    }
    shMaxAlong = 16 * log(showerEnergy / 15);
    // The 95% containment is reduced a bit at higher energy
    double scale = 2.75 - 9.29E-4 * showerEnergy;
    if (scale < 2) scale = 2;
    along95 = scale * shMaxAlong;
  } // ShowerParams

  double ShowerParamTransRMS(double showerEnergy, double along)
  {
    // returns the pareameterized width rms of a shower at along relative to the shower max
    double shMaxAlong, shE95Along;
    ShowerParams(showerEnergy, shMaxAlong, shE95Along);
    if (shMaxAlong <= 0) return 0;
    double tau = (along + shMaxAlong) / shMaxAlong;
    // The shower width is modeled as a simple cone that scales with tau
    double rms = -0.4 + 2.5 * tau;
    if (rms < 0.5) rms = 0.5;
    return rms;
  } // ShowerParamTransRMS

  double InShowerProbLong(double showerEnergy, double along)
  {
    // Returns the likelihood that the point at position along (cm) is inside an EM shower
    // having showerEnergy (MeV). The variable along is relative to shower max.

    if (showerEnergy < 10) return 0;

    double shMaxAlong, shE95Along;
    ShowerParams(showerEnergy, shMaxAlong, shE95Along);
    // 50% of the shower energy is deposited between 0 < shMaxAlong < 1, which should be obvious considering
    // that is the definition of the shower max, so the probability should be ~1 at shMaxAlong = 1.
    // The Geant study shows that 95% of the energy is contained within 2.5 * shMax and has a small dependence
    // on the shower energy, which is modeled in ShowerParams. This function uses a
    // sigmoid likelihood function is constructed with these constraints using the scaling variable tau
    double tau = (along + shMaxAlong) / shMaxAlong;
    if (tau < -1 || tau > 4) return 0;

    double tauHalf, width;
    if (tau > 0) {
      tauHalf = 1.7;
      width = 0.35;
    }
    else {
      // Allow for some uncertainty in the shower start position
      tau = -tau;
      tauHalf = 0.2;
      width = 0.1;
    }

    double prob = 1 / (1 + exp((tau - tauHalf) / width));
    return prob;

  } // InShowrProbLong

  double InShowerProbTrans(double showerEnergy, double along, double trans)
  {
    // Returns the likelihood that the point, (along, trans) (cm), is inside an EM shower having energy showerEnergy (MeV)
    // where along is relative to the shower start position and trans is the radial distance.

    if (showerEnergy < 10) return 0;
    double rms = ShowerParamTransRMS(showerEnergy, along);
    trans = std::abs(trans);
    double prob = exp(-0.5 * trans / rms);
    return prob;

  } // InShowerProbTrans

  double InShowerProbParam(double showerEnergy, double along, double trans)
  {
    return InShowerProbLong(showerEnergy, along) * InShowerProbTrans(showerEnergy, along, trans);
  } // InShowerProbParam

  float InShowerProb(TCSlice& slc, const ShowerStruct3D& ss3, const PFPStruct& pfp)
  {
    // returns a likelihood (0 - 1) that the pfp particle belongs in shower ss3

    if (ss3.ID == 0 || pfp.ID == 0) return 0;
    float sum = 0;
    float cnt = 0;
    for (auto cid : ss3.CotIDs) {
      auto& ss = slc.cots[cid - 1];
      if (ss.ID == 0) continue;
      for (auto tid : pfp.TjIDs) {
        auto& tj = slc.tjs[tid - 1];
        if (tj.CTP != ss.CTP) continue;
        sum += InShowerProb(slc, ss, tj);
        ++cnt;
      } // tid
    }   //cid
    if (cnt == 0) return 0;
    return sum / cnt;

  } // InShowerProb

  float InShowerProb(TCSlice& slc, const ShowerStruct& ss, const Trajectory& tj)
  {
    // returns a likelihood (0 - 1) that the tj particle belongs in shower ss
    // Keep it simple: construct a FOM, take the inverse and limit it to the range 0 - 1
    if (ss.ID == 0 || tj.ID == 0) return 0;
    if (ss.CTP != tj.CTP) return 0;

    auto& stj = slc.tjs[ss.ShowerTjID - 1];
    if (stj.Pts.size() != 3) return 0;
    unsigned short closePt1, closePt2;
    float doca = 1E6;
    TrajTrajDOCA(slc, stj, tj, closePt1, closePt2, doca);
    if (doca == 1E6) return 0;
    float showerLen = PosSep(stj.Pts[0].Pos, stj.Pts[2].Pos);
    // make a rough separation cut. Return a small but non-zero value
    if (doca > 5 * showerLen) return 0.01;
    auto& stp = stj.Pts[closePt1];
    if (stp.DeltaRMS == 0) return 0;
    auto& ttp = tj.Pts[closePt2];
    Point2_t alongTrans;
    FindAlongTrans(stp.Pos, stp.Dir, ttp.Pos, alongTrans);
    float rms = stp.DeltaRMS;
    if (rms < 1) rms = 1;
    float arg = alongTrans[1] / rms;
    float radProb = exp(-0.5 * arg * arg);
    // This is a fake but may be OK if this function is called before the shower is well-defined
    rms = showerLen;
    arg = alongTrans[0] / rms;
    float longProb = exp(-0.5 * arg * arg);
    float costh = std::abs(DotProd(stp.Dir, ttp.Dir));
    float prob = radProb * longProb * costh;
    return prob;

  } // InShowerProb

  float ParentFOM(std::string inFcnLabel,
                  TCSlice& slc,
                  PFPStruct& pfp,
                  ShowerStruct3D& ss3,
                  bool prt)
  {
    // Returns an average weighted parent FOM for all trajectories in the pfp being a parent of the 2D showers in ss3
    if (ss3.ID == 0) return 1000;
    float sum = 0;
    float wsum = 0;
    std::string fcnLabel = inFcnLabel + ".P3FOM";
    float dum1, dum2;
    for (auto cid : ss3.CotIDs) {
      auto& ss = slc.cots[cid - 1];
      if (ss.ID == 0) continue;
      // look for the 3D matched tj in this CTP
      int tjid = 0;
      for (auto tid : pfp.TjIDs) {
        auto& tj = slc.tjs[tid - 1];
        if (tj.ID == 0) continue;
        if (tj.CTP == ss.CTP) tjid = tid;
      } // tid
      if (tjid == 0) continue;
      auto& ptj = slc.tjs[tjid - 1];
      auto& stj = slc.tjs[ss.ShowerTjID - 1];
      // determine which end is farthest away from the shower center
      unsigned short ptjEnd = FarEnd(ptj, stj.Pts[1].Pos);
      auto& farTP = ptj.Pts[ptj.EndPt[ptjEnd]];
      float chgCtrSep2 = PosSep2(farTP.Pos, stj.Pts[1].Pos);
      if (chgCtrSep2 < PosSep2(farTP.Pos, stj.Pts[0].Pos) &&
          chgCtrSep2 < PosSep2(farTP.Pos, stj.Pts[2].Pos))
        continue;
      float fom = ParentFOM(fcnLabel, slc, ptj, ptjEnd, ss, dum1, dum2, prt);
      // ignore failures
      if (fom > 50) continue;
      // weight by the 1/aspect ratio
      float wt = 1;
      if (ss.AspectRatio > 0) wt = 1 / ss.AspectRatio;
      sum += wt * fom;
      wsum += wt;
    } // cid
    if (wsum == 0) return 100;
    float fom = sum / wsum;
    if (prt)
      mf::LogVerbatim("TC") << fcnLabel << " 3S" << ss3.ID << " P" << pfp.ID << " fom "
                            << std::fixed << std::setprecision(3) << fom;
    return fom;
  } // ParentFOM

  float ParentFOM(std::string inFcnLabel,
                  TCSlice& slc,
                  Trajectory& tj,
                  unsigned short& tjEnd,
                  ShowerStruct& ss,
                  float& tp1Sep,
                  float& vx2Score,
                  bool prt)
  {
    // returns a FOM for the trajectory at the end point being the parent of ss and the end which
    // was matched.

    vx2Score = 0;
    tp1Sep = 0;

    if (tjEnd > 1) return 1000;
    if (ss.Energy == 0) return 1000;

    if (ss.ID == 0) return 1000;
    if (ss.TjIDs.empty()) return 1000;
    if (ss.ShowerTjID == 0) return 1000;

    std::string fcnLabel = inFcnLabel + ".PFOM";

    if (ss.AspectRatio > 0.5) {
      if (prt)
        mf::LogVerbatim("TC") << fcnLabel << " 2S" << ss.ID << " poor AspectRatio "
                              << ss.AspectRatio << " FOM not calculated";
      return 100;
    }

    float fom = 0;
    float cnt = 0;
    auto& stj = slc.tjs[ss.ShowerTjID - 1];
    TrajPoint& stp0 = stj.Pts[0];
    // Shower charge center TP
    TrajPoint& stp1 = stj.Pts[1];
    // get the end that is farthest away from the shower center
    tjEnd = FarEnd(tj, stp1.Pos);
    // prospective parent TP
    TrajPoint& ptp = tj.Pts[tj.EndPt[tjEnd]];
    // find the along and trans components in WSE units relative to the
    // shower center
    Point2_t alongTrans;
    FindAlongTrans(stp1.Pos, stp1.Dir, ptp.Pos, alongTrans);
    // We can return here if the shower direction is well defined and
    // alongTrans[0] is > 0
    if (ss.AspectRatio < 0.2 && ss.DirectionFOM < 0.5 && alongTrans[0] > 0) return 100;
    tp1Sep = std::abs(alongTrans[0]);
    // Find the expected shower start relative to shower max (cm)
    double shMaxAlong, shE95Along;
    ShowerParams(ss.Energy, shMaxAlong, shE95Along);
    double alongcm = tcc.wirePitch * tp1Sep;
    // InShowerProbLong expects the longitudinal distance relative to shower max so it
    // should be < 0
    float prob = InShowerProbLong(ss.Energy, -alongcm);
    if (prob < 0.05) return 100;
    // The transverse position must certainly be less than the longitudinal distance
    // to shower max.
    if (alongTrans[1] > shMaxAlong) return 100;
    // longitudinal contribution to fom with 1 Xo error error (14 cm)
    float longFOM = std::abs(alongcm + shMaxAlong) / 14;
    fom += longFOM;
    ++cnt;
    // transverse contribution
    float transFOM = -1;
    if (stp0.DeltaRMS > 0) {
      transFOM = alongTrans[1] / stp0.DeltaRMS;
      fom += transFOM;
      ++cnt;
    }
    // make a tp between the supposed parent TP and the shower center
    TrajPoint tp;
    if (!MakeBareTrajPoint(ptp, stp1, tp)) return 100;
    // we have three angles to compare. The ptp angle, the shower angle and
    // the tp angle.
    float dang1 = DeltaAngle(ptp.Ang, stp1.Ang);
    float dang1FOM = dang1 / 0.1;
    fom += dang1FOM;
    ++cnt;
    float dang2 = DeltaAngle(ptp.Ang, tp.Ang);
    float dang2FOM = dang1 / 0.1;
    fom += dang2FOM;
    ++cnt;
    // the environment near the parent start should be clean.
    std::vector<int> tjlist(1);
    tjlist[0] = tj.ID;
    // check for a vertex at this end and include the vertex tjs if the vertex is close
    // to the expected shower max position
    float vx2Sep = 0;
    // put in a largish FOM value for Tjs that don't have a vertex
    float vxFOM = 10;
    if (tj.VtxID[tjEnd] > 0) {
      VtxStore& vx2 = slc.vtxs[tj.VtxID[tjEnd] - 1];
      vx2Sep = PosSep(vx2.Pos, stp1.Pos);
      vx2Score = vx2.Score;
      tjlist = GetAssns(slc, "2V", vx2.ID, "T");
      vxFOM = std::abs(shMaxAlong - vx2Sep) / 20;
    } // 2D vertex exists
    fom += vxFOM;
    ++cnt;
    float chgFrac = ChgFracNearPos(slc, ptp.Pos, tjlist);
    float chgFracFOM = (1 - chgFrac) / 0.1;
    fom += chgFracFOM;
    ++cnt;
    // Fraction of wires that have a signal between the parent start and the shower center
    float chgFracBtw = ChgFracBetween(ptp, stp1.Pos[0]);
    float chgFrcBtwFOM = (1 - chgFrac) / 0.05;
    fom += chgFrcBtwFOM;
    ++cnt;

    // take the average
    fom /= cnt;
    // divide by the InShowerProbability
    fom /= prob;

    if (prt) {
      mf::LogVerbatim myprt("TC");
      myprt << fcnLabel;
      myprt << " 2S" << ss.ID;
      myprt << " T" << tj.ID << "_" << tjEnd << " Pos " << PrintPos(ptp);
      myprt << std::fixed << std::setprecision(2);
      myprt << " along " << std::fixed << std::setprecision(1) << alongTrans[0] << " fom "
            << longFOM;
      myprt << " trans " << alongTrans[1] << " fom " << transFOM;
      myprt << " prob " << prob;
      myprt << " dang1 " << dang1 << " fom " << dang1FOM;
      myprt << " dang2 " << dang2 << " fom " << dang2FOM;
      myprt << " vx2Score " << vx2Score << " fom " << vxFOM;
      myprt << " chgFrac " << chgFrac << " fom " << chgFracFOM;
      myprt << " chgFracBtw " << chgFracBtw << " fom " << chgFrcBtwFOM;
      myprt << " FOM " << fom;
    }
    return fom;

  } // ParentFOM

  bool WrongSplitTj(std::string inFcnLabel,
                    TCSlice& slc,
                    Trajectory& tj,
                    unsigned short tjEnd,
                    bool prt)
  {
    // Returns true if the trajectory was split by a 3D vertex match and the end of this trajectory is further
    // away from the shower than the partner trajectory
    // Here is a cartoon showing what we are trying to prevent. The shower is represented by a box. The trajectory
    // that is shown as (---*---) was originally reconstructed as a single trajectory. It was later split at the * position
    // by matching in 3D into two trajectories with ID = 1 and 2. We don't want to consider Tj 1 using end 0 as a parent for
    // the shower. Tj is more likely to be the real parent
    //
    //  1111111111 2222222  TjID
    //  0        1 0     1  Tj end
    //               --------------
    //               |            |
    //  ----------*-------        |
    //               |            |
    //               --------------
    if (!tj.AlgMod[kComp3DVx]) return false;
    if (tjEnd > 1) return false;

    std::string fcnLabel = inFcnLabel + ".WSTj";

    // See if the other end is the end that was split. It should have a vertex with Topo = 8 or 11
    unsigned short otherEnd = 1 - tjEnd;
    //    if(prt) mf::LogVerbatim("TC")<<"WSTj: otherEnd "<<otherEnd<<" vtxID "<<tj.VtxID[otherEnd];
    if (tj.VtxID[otherEnd] == 0) return false;
    unsigned short ivx = tj.VtxID[otherEnd] - 1;
    // A vertex exists but not a 3D split vertex
    if (slc.vtxs[ivx].Topo != 8 && slc.vtxs[ivx].Topo != 10) return false;
    if (prt)
      mf::LogVerbatim("TC") << fcnLabel << " Primary candidate " << tj.ID
                            << " was split by a 3D vertex";
    return true;

  } // WrongSplitTj

  void MergeNearby2DShowers(std::string inFcnLabel, TCSlice& slc, const CTP_t& inCTP, bool prt)
  {
    if (!tcc.useAlg[kMergeNrShowers]) return;
    if (slc.cots.empty()) return;

    std::string fcnLabel = inFcnLabel + ".MNS";

    if (prt) {
      mf::LogVerbatim myprt("TC");
      myprt << fcnLabel << " list";
      for (auto& ss : slc.cots) {
        if (ss.CTP != inCTP) continue;
        if (ss.ID == 0) continue;
        myprt << "  ss.ID " << ss.ID << " NearTjs";
        for (auto& id : ss.NearTjIDs)
          myprt << " " << id;
        myprt << "\n";
      }
    } // prt

    bool keepMerging = true;
    while (keepMerging) {
      keepMerging = false;
      for (unsigned short ci1 = 0; ci1 < slc.cots.size() - 1; ++ci1) {
        ShowerStruct& ss1 = slc.cots[ci1];
        if (ss1.CTP != inCTP) continue;
        if (ss1.ID == 0) continue;
        if (ss1.TjIDs.empty()) continue;
        // put the inshower tjs and the nearby tjs into one list
        std::vector<int> ss1list = ss1.TjIDs;
        ss1list.insert(ss1list.end(), ss1.NearTjIDs.begin(), ss1.NearTjIDs.end());
        for (unsigned short ci2 = ci1 + 1; ci2 < slc.cots.size(); ++ci2) {
          ShowerStruct& ss2 = slc.cots[ci2];
          if (ss2.CTP != inCTP) continue;
          if (ss2.ID == 0) continue;
          if (ss2.TjIDs.empty()) continue;
          if (DontCluster(slc, ss1.TjIDs, ss2.TjIDs)) continue;
          std::vector<int> ss2list = ss2.TjIDs;
          ss2list.insert(ss2list.end(), ss2.NearTjIDs.begin(), ss2.NearTjIDs.end());
          std::vector<int> shared = SetIntersection(ss1list, ss2list);
          if (shared.empty()) continue;
          if (prt) {
            mf::LogVerbatim myprt("TC");
            myprt << fcnLabel << " Merge 2S" << ss2.ID << " into 2S" << ss1.ID
                  << "? shared nearby:";
            for (auto tjid : shared)
              myprt << " T" << tjid;
          } // prt
          // add the shared Tjs to ss1 if they meet the requirements
          bool doMerge = false;
          for (auto& tjID : shared) {
            bool inSS1 = (std::find(ss1.TjIDs.begin(), ss1.TjIDs.end(), tjID) != ss1.TjIDs.end());
            bool inSS2 = (std::find(ss2.TjIDs.begin(), ss2.TjIDs.end(), tjID) != ss2.TjIDs.end());
            if (inSS1 && !inSS2) doMerge = true;
            if (!inSS1 && inSS2) doMerge = true;
            // need to add it?
            if (inSS1 || inSS2) continue;
            auto& tj = slc.tjs[tjID - 1];
            // ignore long muons
            if (tj.PDGCode == 13 && tj.Pts.size() > 100 && tj.ChgRMS < 0.5) {
              if (prt)
                mf::LogVerbatim("TC")
                  << fcnLabel << " T" << tj.ID << " looks like a muon. Don't add it";
              continue;
            }
            // see if it looks like a muon in 3D
            if (tj.AlgMod[kMat3D]) {
              auto TInP = GetAssns(slc, "T", tj.ID, "P");
              if (!TInP.empty()) {
                auto& pfp = slc.pfps[TInP[0] - 1];
                if (pfp.PDGCode == 13 && MCSMom(slc, pfp.TjIDs) > 500) continue;
              } // TInP not empty
            }   // 3D matched
            if (AddTj(fcnLabel, slc, tjID, ss1, false, prt)) doMerge = true;
          } // tjID
          if (!doMerge) continue;
          if (MergeShowersAndStore(fcnLabel, slc, ss1.ID, ss2.ID, prt)) {
            Trajectory& stj = slc.tjs[ss1.ShowerTjID - 1];
            stj.AlgMod[kMergeNrShowers] = true;
            if (prt) mf::LogVerbatim("TC") << fcnLabel << " success";
            keepMerging = true;
            break;
          }
        } // ci2
      }   // ci1
    }     // keepMerging

    ChkAssns(fcnLabel, slc);

  } //MergeNearby2DShowers

  void MergeOverlap(std::string inFcnLabel, TCSlice& slc, const CTP_t& inCTP, bool prt)
  {
    // Merge showers whose envelopes overlap each other

    /*
     # 0 Mode (<= 0 OFF, 1 = find showers before 3D match, 2 = find showers after 3D match)
     # 1 Max Tj MCSMom for a shower tag
     # 2 Max separation
     # 3 Min energy (MeV)
     # 4 rms width factor
     # 5 Min shower 1/2 width (WSE units)
     # 6 Min total Tj Pts
     # 7 Min Tjs
     # 8 max parent FOM
     # 9 max direction FOM
     # 10 max aspect ratio
     # 11 Debug in CTP (>10 debug cotID + 10)
     */

    if (tcc.showerTag[2] <= 0) return;
    if (!tcc.useAlg[kMergeOverlap]) return;
    if (slc.cots.empty()) return;

    std::string fcnLabel = inFcnLabel + ".MO";

    // Require that the maximum separation is about two radiation lengths
    if (prt)
      mf::LogVerbatim("TC") << fcnLabel << " checking using separation cut " << tcc.showerTag[2];

    float sepCut2 = tcc.showerTag[2] * tcc.showerTag[2];

    // Iterate if a merge is done
    bool didMerge = true;
    while (didMerge) {
      didMerge = false;
      // See if the envelopes overlap
      for (unsigned short ict = 0; ict < slc.cots.size() - 1; ++ict) {
        auto& iss = slc.cots[ict];
        if (iss.ID == 0) continue;
        if (iss.TjIDs.empty()) continue;
        if (iss.CTP != inCTP) continue;
        for (unsigned short jct = ict + 1; jct < slc.cots.size(); ++jct) {
          auto& jss = slc.cots[jct];
          if (jss.ID == 0) continue;
          if (jss.TjIDs.empty()) continue;
          if (jss.CTP != iss.CTP) continue;
          if (DontCluster(slc, iss.TjIDs, jss.TjIDs)) continue;
          bool doMerge = false;
          for (auto& ivx : iss.Envelope) {
            doMerge = PointInsideEnvelope(ivx, jss.Envelope);
            if (doMerge) break;
          } // ivx
          if (!doMerge) {
            for (auto& jvx : jss.Envelope) {
              doMerge = PointInsideEnvelope(jvx, iss.Envelope);
              if (doMerge) break;
            } // ivx
          }
          if (!doMerge) {
            // check proximity between the envelopes
            for (auto& ivx : iss.Envelope) {
              for (auto& jvx : jss.Envelope) {
                if (PosSep2(ivx, jvx) < sepCut2) {
                  if (prt)
                    mf::LogVerbatim("TC")
                      << fcnLabel << " Envelopes 2S" << iss.ID << " 2S" << jss.ID << " are close "
                      << PosSep(ivx, jvx) << " cut " << tcc.showerTag[2];
                  doMerge = true;
                  break;
                }
              } // jvx
              if (doMerge) break;
            } // ivx
          }   // !domerge
          if (!doMerge) continue;
          // check the relative positions and angle differences. Determine which tps are the
          // closest. Don't merge if the closest points are at the shower start and the angle
          // difference is large
          unsigned short iClosePt = 0;
          unsigned short jClosePt = 0;
          float close = 1E6;
          auto& istj = slc.tjs[iss.ShowerTjID - 1];
          auto& jstj = slc.tjs[jss.ShowerTjID - 1];
          for (unsigned short ipt = 0; ipt < 3; ++ipt) {
            for (unsigned short jpt = 0; jpt < 3; ++jpt) {
              float sep = PosSep2(istj.Pts[ipt].Pos, jstj.Pts[jpt].Pos);
              if (sep < close) {
                close = sep;
                iClosePt = ipt;
                jClosePt = jpt;
              }
            } // jpt
          }   // ipt
          float costh = DotProd(istj.Pts[0].Dir, jstj.Pts[0].Dir);
          if (iClosePt == 0 && jClosePt == 0 && costh < 0.955) {
            if (prt)
              mf::LogVerbatim("TC")
                << fcnLabel << " showers are close at the start points with costh " << costh
                << ". Don't merge";
            continue;
          }
          if (prt) mf::LogVerbatim("TC") << fcnLabel << " Merge " << iss.ID << " and " << jss.ID;
          if (MergeShowersAndStore(fcnLabel, slc, iss.ID, jss.ID, prt)) {
            Trajectory& stj = slc.tjs[iss.ShowerTjID - 1];
            stj.AlgMod[kMergeOverlap] = true;
            didMerge = true;
            break;
          }
          else {
            if (prt) mf::LogVerbatim("TC") << fcnLabel << " Merge failed";
          }
        } // jct
      }   // ict
    }     // didMerge

    ChkAssns(fcnLabel, slc);

  } // MergeOverlap

  void MergeShowerChain(std::string inFcnLabel, TCSlice& slc, const CTP_t& inCTP, bool prt)
  {
    // Merge chains of 3 or more showers that lie on a line

    if (!tcc.useAlg[kMergeShChain]) return;

    std::string fcnLabel = inFcnLabel + ".MSC";

    if (prt) mf::LogVerbatim("TC") << fcnLabel << ": MergeShowerChain inCTP " << inCTP;

    std::vector<int> sids;
    std::vector<TrajPoint> tpList;
    for (unsigned short ict = 0; ict < slc.cots.size(); ++ict) {
      ShowerStruct& iss = slc.cots[ict];
      if (iss.ID == 0) continue;
      if (iss.TjIDs.empty()) continue;
      if (iss.CTP != inCTP) continue;
      // ignore wimpy showers
      if (iss.Energy < 50) continue;
      // save the shower ID
      sids.push_back(iss.ID);
      // and the shower center TP
      tpList.push_back(slc.tjs[iss.ShowerTjID - 1].Pts[1]);
    } // ict
    if (sids.size() < 3) return;

    // sort by wire so the chain order is reasonable
    std::vector<SortEntry> sortVec(sids.size());
    for (unsigned short ii = 0; ii < sortVec.size(); ++ii) {
      sortVec[ii].index = ii;
      sortVec[ii].val = tpList[ii].Pos[0];
    }
    std::sort(sortVec.begin(), sortVec.end(), valsDecreasing);
    auto tsids = sids;
    auto ttpList = tpList;
    for (unsigned short ii = 0; ii < sortVec.size(); ++ii) {
      unsigned short indx = sortVec[ii].index;
      sids[ii] = tsids[indx];
      tpList[ii] = ttpList[indx];
    }

    // TODO: These cuts should be generalized somehow
    float minSep = 150;
    float maxDelta = 30;
    for (unsigned short ii = 0; ii < sids.size() - 2; ++ii) {
      auto& iss = slc.cots[sids[ii] - 1];
      if (iss.ID == 0) continue;
      unsigned short jj = ii + 1;
      auto& jss = slc.cots[sids[jj] - 1];
      if (jss.ID == 0) continue;
      std::vector<int> chain;
      float sepij = PosSep(tpList[ii].Pos, tpList[jj].Pos);
      if (sepij > minSep) continue;
      bool skipit = DontCluster(slc, iss.TjIDs, jss.TjIDs);
      if (prt)
        mf::LogVerbatim("TC") << fcnLabel << " i2S" << iss.ID << " " << PrintPos(tpList[ii].Pos)
                              << " j2S" << jss.ID << " " << PrintPos(tpList[jj].Pos) << " sepij "
                              << sepij << " skipit? " << skipit;
      if (skipit) continue;
      // draw a line between these points
      TrajPoint tp;
      MakeBareTrajPoint(tpList[ii], tpList[jj], tp);
      for (unsigned short kk = jj + 1; kk < sids.size(); ++kk) {
        auto& kss = slc.cots[sids[kk] - 1];
        if (kss.ID == 0) continue;
        if (DontCluster(slc, iss.TjIDs, kss.TjIDs)) continue;
        if (DontCluster(slc, jss.TjIDs, kss.TjIDs)) continue;
        float sepjk = PosSep(tpList[jj].Pos, tpList[kk].Pos);
        float delta = PointTrajDOCA(tpList[kk].Pos[0], tpList[kk].Pos[1], tp);
        if (prt) {
          mf::LogVerbatim myprt("TC");
          myprt << fcnLabel << "   k2S" << kss.ID << " " << PrintPos(tpList[kk].Pos) << " sepjk "
                << sepjk << " delta " << delta;
          if (sepjk > minSep || delta > maxDelta) {
            myprt << " failed separation " << minSep << " or delta cut " << maxDelta;
          }
          else {
            myprt << " add to the chain";
          }
        } // prt
        if (sepjk > minSep || delta > maxDelta) {
          // clear a short chain?
          if (chain.size() > 2) {
            // merge this chain
            int newID = MergeShowers(fcnLabel, slc, chain, prt);
            if (prt) {
              mf::LogVerbatim myprt("TC");
              myprt << fcnLabel << " merged chain";
              for (auto ssID : chain)
                myprt << " 2S" << ssID;
              myprt << " -> 2S" << newID;
            } // prt
          }   // long chain
          chain.clear();
          break;
        }
        else {
          // add this shower to the chain
          if (chain.empty()) {
            chain.resize(3);
            chain[0] = sids[ii];
            chain[1] = sids[jj];
            chain[2] = sids[kk];
          }
          else {
            chain.push_back(sids[kk]);
          }
          // Refine the TP position and direction
          MakeBareTrajPoint(tpList[ii], tpList[kk], tp);
        } // add to an existing chain
      }   // kk
      // push the last one
      if (chain.size() > 2) {
        int newID = MergeShowers(fcnLabel, slc, chain, prt);
        if (prt) {
          mf::LogVerbatim myprt("TC");
          myprt << fcnLabel << " merged chain";
          for (auto ssID : chain)
            myprt << " " << ssID;
          myprt << " -> new ssID " << newID;
        } // prt
      }   // long chain
    }     // ii

    ChkAssns(fcnLabel, slc);

  } // MergeShowerChain

  void MergeSubShowersTj(std::string inFcnLabel, TCSlice& slc, const CTP_t& inCTP, bool prt)
  {
    // merge small showers that are downstream of shower-like tjs. This algorithm is written
    // for low-energy showers with are likely to be sparse and poorly defined.

    if (!tcc.useAlg[kMergeSubShowersTj]) return;

    std::string fcnLabel = inFcnLabel + ".MSSTj";

    struct TjSS {
      int ssID;
      int tjID;
      float dang;
    };
    std::vector<TjSS> tjss;

    // temp vector for DontCluster
    std::vector<int> tjid(1);
    for (auto& ss : slc.cots) {
      if (ss.ID == 0) continue;
      if (ss.CTP != inCTP) continue;
      // TODO: Evaluate this cut
      if (ss.Energy > 300) continue;
      auto& stj = slc.tjs[ss.ShowerTjID - 1];
      auto stp0 = stj.Pts[0];
      float bestDang = 0.3;
      int bestTj = 0;
      // look for a Tj that has higher energy than the shower
      for (auto& tj : slc.tjs) {
        if (tj.AlgMod[kKilled]) continue;
        if (tj.AlgMod[kHaloTj]) continue;
        if (tj.CTP != ss.CTP) continue;
        // require that it isn't in any shower
        if (tj.SSID > 0) continue;
        // require it to be not short
        if (NumPtsWithCharge(slc, tj, false) < 10) continue;
        // and satisfy the ShowerLike MCSMom cut. It is unlikely to be tagged shower-like
        if (tj.MCSMom > tcc.showerTag[1]) continue;
        // check consistency
        tjid[0] = tj.ID;
        if (DontCluster(slc, tjid, ss.TjIDs)) continue;
        float tjEnergy = ChgToMeV(tj.TotChg);
        // find the end that is furthest away from the shower center
        unsigned short farEnd = FarEnd(tj, stj.Pts[1].Pos);
        // compare MCSMom at the far end and the near end
        unsigned short midpt = 0.5 * (tj.EndPt[0] + tj.EndPt[1]);
        float mom1 = MCSMom(slc, tj, tj.EndPt[farEnd], midpt);
        float mom2 = MCSMom(slc, tj, tj.EndPt[1 - farEnd], midpt);
        float asym = (mom1 - mom2) / (mom1 + mom2);
        auto& farTP = tj.Pts[tj.EndPt[farEnd]];
        // IP btw the far end TP and the shower center
        float doca = PointTrajDOCA(stp0.Pos[0], stp0.Pos[1], farTP);
        float sep = PosSep(farTP.Pos, stp0.Pos);
        float dang = doca / sep;
        if (prt) {
          mf::LogVerbatim myprt("TC");
          myprt << fcnLabel << " Candidate 2S" << ss.ID << " T" << tj.ID << "_" << farEnd;
          myprt << " ShEnergy " << (int)ss.Energy << " tjEnergy " << (int)tjEnergy;
          myprt << " doca " << doca << " sep " << sep << " dang " << dang << " asym " << asym;
        }
        if (tjEnergy < ss.Energy) continue;
        if (asym < 0.5) continue;
        // TODO: This should be done more carefully
        // separation cut 100 WSE ~ 30 cm in uB
        if (sep > 100) continue;
        if (dang > bestDang) continue;
        bestDang = dang;
        bestTj = tj.ID;
      } // tj
      if (bestTj == 0) continue;
      TjSS match;
      match.ssID = ss.ID;
      match.tjID = bestTj;
      match.dang = bestDang;
      tjss.push_back(match);
    } // ss

    if (tjss.empty()) return;

    // ensure that a tj is only put in one shower
    bool keepGoing = true;
    while (keepGoing) {
      keepGoing = false;
      float bestDang = 0.3;
      int bestMatch = 0;
      for (unsigned short mat = 0; mat < tjss.size(); ++mat) {
        auto& match = tjss[mat];
        // already used
        if (match.dang < 0) continue;
        if (match.dang < bestDang) bestMatch = mat;
      } // mat
      if (bestMatch > 0) {
        auto& match = tjss[bestMatch];
        auto& ss = slc.cots[match.ssID - 1];
        if (!AddTj(fcnLabel, slc, match.tjID, ss, true, prt)) {
          if (prt) mf::LogVerbatim("TC") << " Failed";
          continue;
        }
        match.dang = -1;
        // set the AlgMod bit
        auto& stj = slc.tjs[ss.ShowerTjID - 1];
        stj.AlgMod[kMergeSubShowersTj] = true;
        keepGoing = true;
      } // found bestMatch
    }   // keepGoing

    ChkAssns(fcnLabel, slc);

  } // MergeSubShowersTj

  void MergeSubShowers(std::string inFcnLabel, TCSlice& slc, const CTP_t& inCTP, bool prt)
  {
    // Merge small showers that are downstream of larger showers

    if (!tcc.useAlg[kMergeSubShowers]) return;

    std::string fcnLabel = inFcnLabel + ".MSS";
    bool newCuts = (tcc.showerTag[0] == 4);
    constexpr float radLen = 14 / 0.3;

    if (prt) {
      if (newCuts) {
        mf::LogVerbatim("TC") << fcnLabel << " MergeSubShowers checking using ShowerParams";
      }
      else {
        mf::LogVerbatim("TC") << fcnLabel
                              << " MergeSubShowers checking using radiation length cut ";
      }
    } // prt

    bool keepMerging = true;
    while (keepMerging) {
      keepMerging = false;
      // sort by decreasing energy
      std::vector<SortEntry> sortVec;
      for (auto& ss : slc.cots) {
        if (ss.ID == 0) continue;
        if (ss.CTP != inCTP) continue;
        SortEntry se;
        se.index = ss.ID - 1;
        se.val = ss.Energy;
        sortVec.push_back(se);
      } // ss
      if (sortVec.size() < 2) return;
      std::sort(sortVec.begin(), sortVec.end(), valsIncreasing);
      for (unsigned short ii = 0; ii < sortVec.size() - 1; ++ii) {
        ShowerStruct& iss = slc.cots[sortVec[ii].index];
        if (iss.ID == 0) continue;
        // this shouldn't be done to showers that are ~round
        if (iss.AspectRatio > 0.5) continue;
        TrajPoint& istp1 = slc.tjs[iss.ShowerTjID - 1].Pts[1];
        double shMaxAlong, along95;
        ShowerParams((double)iss.Energy, shMaxAlong, along95);
        // convert along95 to a separation btw shower max and along95
        along95 -= shMaxAlong;
        // convert to WSE
        along95 /= tcc.wirePitch;
        for (unsigned short jj = ii + 1; jj < sortVec.size(); ++jj) {
          ShowerStruct& jss = slc.cots[sortVec[jj].index];
          if (jss.ID == 0) continue;
          if (DontCluster(slc, iss.TjIDs, jss.TjIDs)) continue;
          TrajPoint& jstp1 = slc.tjs[jss.ShowerTjID - 1].Pts[1];
          if (newCuts) {
            // find the longitudinal and transverse separation using the higher energy
            // shower which probably is better defined.
            Point2_t alongTrans;
            FindAlongTrans(istp1.Pos, istp1.Dir, jstp1.Pos, alongTrans);
            // the lower energy shower is at the wrong end of the higher energy shower if alongTrans[0] < 0
            if (alongTrans[0] < 0) continue;
            // increase the cut if the second shower is < 10% of the first shower
            float alongCut = along95;
            if (jss.Energy < 0.1 * iss.Energy) alongCut *= 1.5;
            float probLong = InShowerProbLong(iss.Energy, alongTrans[0]);
            float probTran = InShowerProbTrans(iss.Energy, alongTrans[0], alongTrans[1]);
            if (prt) {
              mf::LogVerbatim myprt("TC");
              myprt << fcnLabel << " Candidate i2S" << iss.ID << " E = " << (int)iss.Energy
                    << " j2S" << jss.ID << " E = " << (int)jss.Energy;
              myprt << " along " << std::fixed << std::setprecision(1) << alongTrans[0] << " trans "
                    << alongTrans[1];
              myprt << " alongCut " << alongCut << " probLong " << probLong << " probTran "
                    << probTran;
            } // prt
            if (alongTrans[0] > alongCut) continue;
            if (alongTrans[1] > alongTrans[0]) continue;
          }
          else {
            // old cuts
            float sep = PosSep(istp1.Pos, jstp1.Pos);
            float trad = sep / radLen;
            // Find the IP between them using the projection of the one with the lowest aspect ratio
            float delta = 9999;
            if (iss.AspectRatio < jss.AspectRatio) {
              delta = PointTrajDOCA(jstp1.Pos[0], jstp1.Pos[1], istp1);
            }
            else {
              delta = PointTrajDOCA(istp1.Pos[0], istp1.Pos[1], jstp1);
            }
            // See if delta is consistent with the cone angle of the i shower
            float dang = delta / sep;
            if (prt)
              mf::LogVerbatim("TC") << fcnLabel << " Candidate i2S" << iss.ID << " j2S" << jss.ID
                                    << " separation " << (int)sep << " radiation lengths " << trad
                                    << " delta " << delta << " dang " << dang;
            if (trad > 3) continue;
            // There must be a correlation between dang and the energy of these showers...
            if (dang > 0.3) continue;
          } // old cuts

          if (prt) mf::LogVerbatim("TC") << fcnLabel << " Merge them. Re-find shower center, etc";
          if (MergeShowersAndStore(fcnLabel, slc, iss.ID, jss.ID, prt)) {
            Trajectory& stj = slc.tjs[iss.ShowerTjID - 1];
            stj.AlgMod[kMergeSubShowers] = true;
            keepMerging = true;
            break;
          }
        } // jj
        if (keepMerging) break;
      } // ii
    }   // keepMerging

    ChkAssns(fcnLabel, slc);

  } // MergeSubShowers

  int MergeShowers(std::string inFcnLabel, TCSlice& slc, std::vector<int> ssIDs, bool prt)
  {
    // merge a list of showers and return the ID of the merged shower.
    // Returns 0 if there was a failure.

    std::string fcnLabel = inFcnLabel + ".MS";
    if (ssIDs.size() < 2) return 0;
    // check for a valid ID
    for (auto ssID : ssIDs)
      if (ssID <= 0 || ssID > (int)slc.cots.size()) return 0;
    // check for the same CTP and consistent assns
    int ss3Assn = 0;
    auto& ss0 = slc.cots[ssIDs[0] - 1];
    std::vector<int> tjl;
    for (auto ssID : ssIDs) {
      auto& ss = slc.cots[ssID - 1];
      if (ss.CTP != ss0.CTP) return 0;
      tjl.insert(tjl.end(), ss.TjIDs.begin(), ss.TjIDs.end());
      if (ss.SS3ID > 0 && ss3Assn == 0) ss3Assn = ss.SS3ID;
      if (ss.SS3ID > 0 && ss.SS3ID != ss3Assn) return 0;
    } // ssID
    // ensure the InShower Tjs are valid
    for (auto tjID : tjl) {
      auto& tj = slc.tjs[tjID - 1];
      if (tj.CTP != ss0.CTP || tj.AlgMod[kKilled]) return 0;
    } // tjID

    // mark the old showers killed
    for (auto ssID : ssIDs) {
      auto& ss = slc.cots[ssID - 1];
      ss.ID = 0;
      // kill the shower Tj
      auto& stj = slc.tjs[ss.ShowerTjID - 1];
      stj.AlgMod[kKilled] = true;
    } // tjID

    // in with the new
    auto newss = CreateSS(slc, tjl);
    if (newss.ID == 0) return 0;

    for (auto tid : tjl) {
      auto& tj = slc.tjs[tid - 1];
      tj.SSID = newss.ID;
    } // tid
    newss.SS3ID = ss3Assn;

    // define the new shower
    if (!UpdateShower(fcnLabel, slc, newss, prt)) {
      MakeShowerObsolete(fcnLabel, slc, newss, prt);
      return 0;
    }
    // store it
    if (!StoreShower(fcnLabel, slc, newss)) {
      MakeShowerObsolete(fcnLabel, slc, newss, prt);
      return 0;
    }
    return newss.ID;

  } // MergeShowers

  bool MergeShowersAndStore(std::string inFcnLabel, TCSlice& slc, int icotID, int jcotID, bool prt)
  {
    // Merge showers using shower indices. The icotID shower is modified in-place.
    // The jcotID shower is declared obsolete. This function also re-defines the shower and
    // preserves the icotID Parent ID.

    if (icotID <= 0 || icotID > (int)slc.cots.size()) return false;
    ShowerStruct& iss = slc.cots[icotID - 1];
    if (iss.ID == 0) return false;
    if (iss.TjIDs.empty()) return false;
    if (iss.ShowerTjID <= 0) return false;

    if (jcotID <= 0 || jcotID > (int)slc.cots.size()) return false;
    ShowerStruct& jss = slc.cots[jcotID - 1];
    if (jss.TjIDs.empty()) return false;
    if (jss.ID == 0) return false;
    if (jss.ShowerTjID <= 0) return false;

    if (iss.CTP != jss.CTP) return false;

    std::string fcnLabel = inFcnLabel + ".MSAS";

    if (iss.SS3ID > 0 && jss.SS3ID > 0 && iss.SS3ID != jss.SS3ID) return false;

    Trajectory& itj = slc.tjs[iss.ShowerTjID - 1];
    Trajectory& jtj = slc.tjs[jss.ShowerTjID - 1];
    if (!itj.Pts[1].Hits.empty() || !jtj.Pts[1].Hits.empty()) return false;

    iss.TjIDs.insert(iss.TjIDs.end(), jss.TjIDs.begin(), jss.TjIDs.end());
    // make a new trajectory using itj as a template
    Trajectory ktj = itj;
    ktj.ID = slc.tjs.size() + 1;

    slc.tjs.push_back(ktj);
    // kill jtj
    MakeTrajectoryObsolete(slc, iss.ShowerTjID - 1);
    MakeTrajectoryObsolete(slc, jss.ShowerTjID - 1);
    slc.tjs[iss.ShowerTjID - 1].ParentID = ktj.ID;
    slc.tjs[jss.ShowerTjID - 1].ParentID = ktj.ID;
    if (prt)
      mf::LogVerbatim("TC") << fcnLabel << " killed stj T" << iss.ShowerTjID << " and T"
                            << jss.ShowerTjID << " new T" << ktj.ID;
    // revise the shower
    iss.ShowerTjID = ktj.ID;
    // transfer the list of Tj IDs
    iss.TjIDs.insert(iss.TjIDs.end(), jss.TjIDs.begin(), jss.TjIDs.begin());
    std::sort(iss.TjIDs.begin(), iss.TjIDs.end());
    // correct the assn
    for (auto tid : iss.TjIDs) {
      auto& tj = slc.tjs[tid - 1];
      tj.SSID = iss.ID;
    } // tid
    // transfer a 2S -> 3S assn
    if (iss.SS3ID == 0 && jss.SS3ID > 0) iss.SS3ID = jss.SS3ID;
    // merge the list of nearby Tjs
    iss.NearTjIDs.insert(iss.NearTjIDs.end(), jss.NearTjIDs.begin(), jss.NearTjIDs.end());
    // transfer the TruParentID if it is in jss
    if (jss.TruParentID > 0) iss.TruParentID = jss.TruParentID;
    iss.NeedsUpdate = true;
    // force a full update
    iss.ShPts.clear();
    jss.ID = 0;
    bool success = UpdateShower(fcnLabel, slc, iss, prt);
    KillVerticesInShower(fcnLabel, slc, iss, prt);

    return success;

  } // MergeShowersAndStore

  bool MergeShowerTjsAndStore(TCSlice& slc, unsigned short istj, unsigned short jstj, bool prt)
  {
    // Merge showers using showerTj indices
    // This function is called from MergeAndStore whose function is to merge two line-like
    // trajectories and store them. This function was called because at least one of the
    // trajectories is a shower Tj. Assume that the decision to merge them has been made elsewhere.

    if (istj > slc.tjs.size() - 1) return false;
    if (jstj > slc.tjs.size() - 1) return false;

    Trajectory& itj = slc.tjs[istj];
    Trajectory& jtj = slc.tjs[jstj];

    std::string fcnLabel = "MSTJ";

    if (prt)
      mf::LogVerbatim("TC") << fcnLabel << " MergeShowerTjsAndStore Tj IDs " << itj.ID << "  "
                            << jtj.ID;

    // First we check to make sure that both are shower Tjs.
    if (!itj.AlgMod[kShowerTj] && !jtj.AlgMod[kShowerTj]) {
      if (prt) mf::LogVerbatim("TC") << " One of these isn't a shower Tj";
      return false;
    }

    // We need to keep the convention used in MergeAndStore to create a new merged trajectory
    // and kill the two fragments. This doesn't require making a new shower however. We can just
    // re-purpose one of the existing showers
    int icotID = GetCotID(slc, itj.ID);
    if (icotID == 0) return false;
    ShowerStruct& iss = slc.cots[icotID - 1];
    if (iss.ID == 0) return false;
    if (iss.TjIDs.empty()) return false;
    int jcotID = GetCotID(slc, jtj.ID);
    if (jcotID == 0) return false;
    ShowerStruct& jss = slc.cots[jcotID - 1];
    if (jss.ID == 0) return false;
    if (jss.TjIDs.empty()) return false;

    return MergeShowersAndStore(fcnLabel, slc, icotID, jcotID, prt);

  } // MergeShowerTjsAndStore

  bool AnalyzeRotPos(std::string inFcnLabel, TCSlice& slc, ShowerStruct& ss, bool prt)
  {
    // The RotPos vector was filled and sorted by increasing distance along the shower axis.
    // This function divides the RotPos points into 3 sections and puts the transverse rms width in the
    // three sections into the shower Tj TrajPoint DeltaRMS variable. It also calculates the charge and number of shower
    // points closest to each TrajPoint. The

    if (ss.ID == 0) return false;
    if (ss.ShPts.empty()) return false;
    Trajectory& stj = slc.tjs[ss.ShowerTjID - 1];
    if (stj.Pts.size() != 3) return false;

    std::string fcnLabel = inFcnLabel + ".ARP";

    for (auto& tp : stj.Pts) {
      tp.Chg = 0;
      tp.DeltaRMS = 0;
      tp.NTPsFit = 0;
      tp.HitPos = {{0.0, 0.0}};
    }

    float minAlong = ss.ShPts[0].RotPos[0];
    float maxAlong = ss.ShPts[ss.ShPts.size() - 1].RotPos[0];
    float sectionLength = (maxAlong - minAlong) / 3;
    float sec0 = minAlong + sectionLength;
    float sec2 = maxAlong - sectionLength;
    // iterate over the shower points (aka hits)
    for (auto& spt : ss.ShPts) {
      // The point on the shower Tj to which the charge will assigned
      unsigned short ipt = 0;
      if (spt.RotPos[0] < sec0) {
        // closest to point 0
        ipt = 0;
      }
      else if (spt.RotPos[0] > sec2) {
        // closest to point 2
        ipt = 2;
      }
      else {
        // closest to point 1
        ipt = 1;
      }
      stj.Pts[ipt].Chg += spt.Chg;
      // Average the absolute value of the transverse position in lieu of
      // using the sum of the squares. The result is ~15% higher than the actual
      // rms which is OK since this is used to find the transverse size of the shower
      // which is not a precisely defined quantity anyway
      stj.Pts[ipt].DeltaRMS += spt.Chg * std::abs(spt.RotPos[1]);
      ++stj.Pts[ipt].NTPsFit;
      // Average the charge center at each point
      stj.Pts[ipt].HitPos[0] += spt.Chg * spt.Pos[0];
      stj.Pts[ipt].HitPos[1] += spt.Chg * spt.Pos[1];
    } // spt

    for (auto& tp : stj.Pts) {
      if (tp.Chg > 0) {
        tp.DeltaRMS /= tp.Chg;
        tp.HitPos[0] /= tp.Chg;
        tp.HitPos[1] /= tp.Chg;
      }
    } // tp

    // require that there is charge in point 0 and 2. Point 1 may not have charge if
    // we are constructing a sparse shower that is not yet well-defined
    if (stj.Pts[0].Chg == 0 || stj.Pts[2].Chg == 0) return false;

    // ensure that the charge center is defined
    if (stj.Pts[1].Chg == 0) {
      // do a simple interpolation
      stj.Pts[1].HitPos[0] = 0.5 * (stj.Pts[0].HitPos[0] + stj.Pts[2].HitPos[0]);
      stj.Pts[1].HitPos[1] = 0.5 * (stj.Pts[0].HitPos[1] + stj.Pts[2].HitPos[1]);
    }
    if (stj.Pts[2].DeltaRMS > 0) { ss.DirectionFOM = stj.Pts[0].DeltaRMS / stj.Pts[2].DeltaRMS; }
    else {
      ss.DirectionFOM = 10;
    }
    if (prt) {
      mf::LogVerbatim myprt("TC");
      myprt << fcnLabel << " 2S" << ss.ID;
      myprt << " HitPos[0] " << std::fixed << std::setprecision(1);
      myprt << stj.Pts[1].HitPos[0] << " " << stj.Pts[1].HitPos[1] << " " << stj.Pts[1].HitPos[2];
      myprt << " DeltaRMS " << std::setprecision(2);
      myprt << stj.Pts[0].DeltaRMS << " " << stj.Pts[1].DeltaRMS << " " << stj.Pts[2].DeltaRMS;
      myprt << " DirectionFOM " << std::fixed << std::setprecision(2) << ss.DirectionFOM;
    }
    return true;

  } // AnalyzeRotPos

  void ReverseShower(std::string inFcnLabel, TCSlice& slc, ShowerStruct& ss, bool prt)
  {
    // Reverses the shower and the shower tj

    if (ss.ID == 0) return;
    if (ss.TjIDs.empty()) return;

    std::string fcnLabel = inFcnLabel + ".RevSh";

    std::reverse(ss.ShPts.begin(), ss.ShPts.end());
    // change the sign of RotPos
    for (auto& sspt : ss.ShPts) {
      sspt.RotPos[0] = -sspt.RotPos[0];
      sspt.RotPos[1] = -sspt.RotPos[1];
    }
    // flip the shower angle
    if (ss.Angle > 0) { ss.Angle -= M_PI; }
    else {
      ss.Angle += M_PI;
    }
    if (ss.DirectionFOM != 0) ss.DirectionFOM = 1 / ss.DirectionFOM;
    auto& stj = slc.tjs[ss.ShowerTjID - 1];
    ReverseTraj(stj);
    DefineEnvelope(fcnLabel, slc, ss, prt);
    if (prt) mf::LogVerbatim("TC") << fcnLabel << " Reversed shower. Shower angle = " << ss.Angle;
  } // ReverseShower

  void ReverseShower(std::string inFcnLabel, TCSlice& slc, int cotID, bool prt)
  {
    // Reverses the shower and the shower tj

    if (cotID > (int)slc.cots.size()) return;
    ShowerStruct& ss = slc.cots[cotID - 1];
    if (ss.ID == 0) return;
    ReverseShower(inFcnLabel, slc, ss, prt);
  }

  void MakeShowerObsolete(std::string inFcnLabel, TCSlice& slc, ShowerStruct3D& ss3, bool prt)
  {
    // set the ss3 ID = 0 and remove 2D shower -> 3D shower associations. The 2D showers are not
    // declared obsolete
    for (auto cid : ss3.CotIDs) {
      if (cid == 0 || (unsigned short)cid > slc.cots.size()) continue;
      auto& ss = slc.cots[cid - 1];
      if (ss.SS3ID > 0 && ss.SS3ID != ss3.ID) continue;
      ss.SS3ID = 0;
    } // cid
    if (prt) {
      std::string fcnLabel = inFcnLabel + ".MSO";
      mf::LogVerbatim("TC") << fcnLabel << " Killed  3S" << ss3.ID;
    }
    ss3.ID = 0;
  } // MakeShowerObsolete

  void MakeShowerObsolete(std::string inFcnLabel, TCSlice& slc, ShowerStruct& ss, bool prt)
  {
    // Gracefully kills the shower and the associated shower Tj

    if (ss.ID == 0) return;

    std::string fcnLabel = inFcnLabel + ".MSO";

    auto& stp1 = slc.tjs[ss.ShowerTjID - 1].Pts[1];
    if (!stp1.Hits.empty()) return;

    // clear a 3S -> 2S assn
    if (ss.SS3ID > 0 && ss.SS3ID <= (int)slc.showers.size()) {
      auto& ss3 = slc.showers[ss.SS3ID - 1];
      std::vector<int> newCIDs;
      for (auto cid : ss3.CotIDs) {
        if (cid != ss.ID) newCIDs.push_back(cid);
      } // cid
      ss3.CotIDs = newCIDs;
    } // ss3 assn exists

    // Kill the shower Tj if it exists. This also releases the hits
    if (ss.ShowerTjID > 0) MakeTrajectoryObsolete(slc, ss.ShowerTjID - 1);

    // Restore the original InShower Tjs
    // Unset the killed bit
    for (auto& tjID : ss.TjIDs) {
      Trajectory& tj = slc.tjs[tjID - 1];
      tj.AlgMod[kKilled] = false;
      // clear all of the shower-related bits
      tj.SSID = 0;
      tj.AlgMod[kShwrParent] = false;
      tj.AlgMod[kMergeOverlap] = false;
      tj.AlgMod[kMergeSubShowers] = false;
      tj.AlgMod[kMergeNrShowers] = false;
      tj.AlgMod[kMergeShChain] = false;
    } // tjID
    if (prt)
      mf::LogVerbatim("TC") << fcnLabel << " Killed 2S" << ss.ID << " and ST" << ss.ShowerTjID;
    ss.ID = 0;

  } // MakeShowerObsolete

  bool DontCluster(TCSlice const& slc,
                   const std::vector<int>& tjlist1,
                   const std::vector<int>& tjlist2)
  {
    // returns true if a pair of tjs in the two lists are in the dontCluster vector
    if (tjlist1.empty() || tjlist2.empty()) return false;
    if (slc.dontCluster.empty()) return false;
    for (auto tid1 : tjlist1) {
      for (auto tid2 : tjlist2) {
        int ttid1 = tid1;
        if (ttid1 > tid2) std::swap(ttid1, tid2);
        for (auto& dc : slc.dontCluster)
          if (dc.TjIDs[0] == ttid1 && dc.TjIDs[1] == tid2) return true;
      } // dc
    }   // tid1
    return false;
  } // DontCluster

  void TagShowerLike(TCSlice& slc, const CTP_t& inCTP)
  {
    // Tag Tjs as InShower if they have MCSMom < ShowerTag[1] and there are more than
    // ShowerTag[6] other Tjs with a separation < ShowerTag[2].

    if (tcc.showerTag[0] <= 0) return;
    if (slc.tjs.size() > 20000) return;
    float typicalChgRMS = 0.5 * (tcc.chargeCuts[1] + tcc.chargeCuts[2]);

    bool prt = (tcc.dbgSlc && tcc.dbg2S && inCTP == debug.CTP);

    // clear out old tags and make a list of Tjs to consider
    std::vector<std::vector<int>> tjLists;
    std::vector<int> tjids;
    for (auto& tj : slc.tjs) {
      if (tj.CTP != inCTP) continue;
      if (tj.AlgMod[kKilled]) continue;
      if (tj.AlgMod[kHaloTj]) continue;
      tj.AlgMod[kShowerLike] = false;
      if (tj.AlgMod[kShowerTj]) continue;
      // ignore Tjs with Bragg peaks
      bool skipit = false;
      for (unsigned short end = 0; end < 2; ++end)
        if (tj.EndFlag[end][kBragg]) skipit = true;
      if (skipit) continue;
      short npwc = NumPtsWithCharge(slc, tj, false);
      // Don't expect any (primary) electron to be reconstructed as a single trajectory for
      // more than ~2 radiation lengths ~ 30 cm for uB ~ 100 wires
      if (npwc > 100) continue;
      // allow short Tjs.
      if (npwc > 5) {
        // Increase the MCSMom cut if the Tj is long and the charge RMS is high to reduce sensitivity
        // to the fcl configuration. A primary electron may be reconstructed as one long Tj with large
        // charge rms and possibly high MCSMom or as several nearby shorter Tjs with lower charge rms
        float momCut = tcc.showerTag[1];
        if (tj.ChgRMS > typicalChgRMS) momCut *= tj.ChgRMS / typicalChgRMS;
        if (tj.MCSMom > momCut) continue;
      }
      tjids.push_back(tj.ID);
    } // tj

    if (tjids.size() < 2) return;

    for (unsigned short it1 = 0; it1 < tjids.size() - 1; ++it1) {
      Trajectory& tj1 = slc.tjs[tjids[it1] - 1];
      for (unsigned short it2 = it1 + 1; it2 < tjids.size(); ++it2) {
        Trajectory& tj2 = slc.tjs[tjids[it2] - 1];
        unsigned short ipt1, ipt2;
        float doca = tcc.showerTag[2];
        // Find the separation between Tjs without considering dead wires
        TrajTrajDOCA(slc, tj1, tj2, ipt1, ipt2, doca, false);
        if (doca == tcc.showerTag[2]) continue;
        // make tighter cuts for user-defined short Tjs
        // found a close pair. See if one of these is in an existing cluster of Tjs
        bool inlist = false;
        for (unsigned short it = 0; it < tjLists.size(); ++it) {
          bool tj1InList =
            (std::find(tjLists[it].begin(), tjLists[it].end(), tj1.ID) != tjLists[it].end());
          bool tj2InList =
            (std::find(tjLists[it].begin(), tjLists[it].end(), tj2.ID) != tjLists[it].end());
          if (tj1InList || tj2InList) {
            // add the one that is not in the list
            if (!tj1InList) tjLists[it].push_back(tj1.ID);
            if (!tj2InList) tjLists[it].push_back(tj2.ID);
            inlist = true;
            break;
          }
          if (inlist) break;
        } // it
        // start a new list with this pair?
        if (!inlist) {
          std::vector<int> newlist(2);
          newlist[0] = tj1.ID;
          newlist[1] = tj2.ID;
          tjLists.push_back(newlist);
        }
      } // it2
    }   // it1
    if (tjLists.empty()) return;

    // mark them all as ShowerLike Tjs
    for (auto& tjl : tjLists) {
      // ignore small clusters
      if (tjl.size() < 3) continue;
      for (auto& tjID : tjl) {
        auto& tj = slc.tjs[tjID - 1];
        tj.AlgMod[kShowerLike] = true;
      } // tjid
    }   // tjl

    if (prt) {
      unsigned short nsh = 0;
      for (auto& tjl : tjLists) {
        for (auto& tjID : tjl) {
          auto& tj = slc.tjs[tjID - 1];
          if (tj.AlgMod[kShowerLike]) ++nsh;
        } // tjid
      }   // tjl
      mf::LogVerbatim("TC") << "TagShowerLike tagged " << nsh << " Tjs vertices in CTP " << inCTP;
    } // prt
  }   // TagShowerLike

  void FindNearbyTjs(std::string inFcnLabel, TCSlice& slc, ShowerStruct& ss, bool prt)
  {
    // Find Tjs that are near the shower but are not included in it
    ss.NearTjIDs.clear();

    // check for a valid envelope
    if (ss.Envelope.empty()) return;
    auto& stj = slc.tjs[ss.ShowerTjID - 1];

    std::string fcnLabel = inFcnLabel + ".FNTj";

    std::vector<int> ntj;

    // set max distance of closest approach ~ 5 radiation lengths ~200 WSE
    constexpr float fiveRadLen = 200;

    // look for vertices inside the envelope
    for (auto vx : slc.vtxs) {
      if (vx.CTP != ss.CTP) continue;
      if (vx.ID == 0) continue;
      if (!PointInsideEnvelope(vx.Pos, ss.Envelope)) continue;
      auto vxTjIDs = GetAssns(slc, "2V", vx.ID, "T");
      for (auto tjID : vxTjIDs) {
        // ignore those that are in the shower
        if (std::find(ss.TjIDs.begin(), ss.TjIDs.end(), tjID) != ss.TjIDs.end()) continue;
        // or already in the list
        if (std::find(ntj.begin(), ntj.end(), tjID) != ntj.end()) continue;
        ntj.push_back(tjID);
      } // tjID
    }   // vx

    // Check for tj points inside the envelope
    for (auto& tj : slc.tjs) {
      if (tj.CTP != ss.CTP) continue;
      if (tj.AlgMod[kKilled]) continue;
      // not a showerTj
      if (tj.AlgMod[kShowerTj]) continue;
      // make sure it's not in the shower
      if (std::find(ss.TjIDs.begin(), ss.TjIDs.end(), tj.ID) != ss.TjIDs.end()) continue;
      // or already in the list
      if (std::find(ntj.begin(), ntj.end(), tj.ID) != ntj.end()) continue;
      // check proximity of long high MCSMom Tjs to the shower center
      if (tj.Pts.size() > 40 && tj.MCSMom > 200) {
        float delta = PointTrajDOCA(stj.Pts[1].Pos[0], stj.Pts[1].Pos[1], tj.Pts[tj.EndPt[0]]);
        // TODO: This could be done much better
        if (delta < 20) {
          float doca = fiveRadLen;
          unsigned short spt = 0, ipt = 0;
          TrajTrajDOCA(slc, stj, tj, spt, ipt, doca);
          if (doca < fiveRadLen) {
            ntj.push_back(tj.ID);
            continue;
          }
        }
      } // long hi-MCSMom tj
      // don't need to check every point. Every third should be enough
      bool isInside = false;
      for (unsigned short ipt = tj.EndPt[0]; ipt < tj.EndPt[1]; ipt += 3) {
        if (PointInsideEnvelope(tj.Pts[ipt].Pos, ss.Envelope)) {
          isInside = true;
          break;
        }
      } // ipt
      // check the last point which was probably missed above
      if (!isInside) {
        unsigned short ipt = tj.EndPt[1];
        isInside = PointInsideEnvelope(tj.Pts[ipt].Pos, ss.Envelope);
      }
      if (isInside) ntj.push_back(tj.ID);
    } // tj
    if (ntj.size() > 1) std::sort(ntj.begin(), ntj.end());
    if (prt)
      mf::LogVerbatim("TC") << fcnLabel << " Found " << ntj.size() << " Tjs near ss.ID " << ss.ID;
    ss.NearTjIDs = ntj;

  } // FindNearbyTjs

  void AddCloseTjsToList(TCSlice& slc, unsigned short itj, std::vector<int> list)
  {
    // Searches the trajectory points for hits that are used in a different trajectory and add
    // them to the list if any are found, and the MCSMomentum is not too large
    if (itj > slc.tjs.size() - 1) return;

    //short maxMom = (short)(2 * tcc.showerTag[1]);
    short maxMom = tcc.showerTag[1];
    //XL: why is maxMom is twice of the shower tag [1]?
    for (auto& tp : slc.tjs[itj].Pts) {
      for (unsigned short ii = 0; ii < tp.Hits.size(); ++ii) {
        // ignore hits that are used in this trajectory
        if (tp.UseHit[ii]) continue;
        unsigned int iht = tp.Hits[ii];
        // ignore if there is no hit -> Tj association
        if (slc.slHits[iht].InTraj <= 0) continue;
        if ((unsigned int)slc.slHits[iht].InTraj > slc.tjs.size()) continue;
        // check the momentum
        Trajectory& tj = slc.tjs[slc.slHits[iht].InTraj - 1];
        if (tj.MCSMom > maxMom) continue;
        //        if(tj.AlgMod[kTjHiVx3Score]) continue;
        // see if it is already in the list
        if (std::find(list.begin(), list.end(), slc.slHits[iht].InTraj) != list.end()) continue;
        list.push_back(slc.slHits[iht].InTraj);
      } // ii
    }   // tp
  }     // AddCloseTjsToList

  void DefineEnvelope(std::string inFcnLabel, TCSlice& slc, ShowerStruct& ss, bool prt)
  {

    if (ss.ID == 0) return;
    if (ss.TjIDs.empty()) return;
    Trajectory& stj = slc.tjs[ss.ShowerTjID - 1];
    // shower Tj isn't fully defined yet
    if (stj.Pts[0].Pos[0] == 0) return;

    std::string fcnLabel = inFcnLabel + ".DE";

    ss.Envelope.resize(4);
    TrajPoint& stp0 = stj.Pts[0];
    TrajPoint& stp1 = stj.Pts[1];
    TrajPoint& stp2 = stj.Pts[2];

    // construct the Envelope polygon. Start with a rectangle using the fixed 1/2 width fcl input
    // expanded by the rms width at each end to create a polygon. The polygon is constructed along
    // the Pos[0] direction and then rotated into the ShowerTj direction. Use sTp1 as the origin.
    // First vertex
    ss.Envelope[0][0] = -PosSep(stp0.Pos, stp1.Pos);
    ss.Envelope[0][1] = tcc.showerTag[5] + tcc.showerTag[4] * stp0.DeltaRMS;
    // second vertex
    ss.Envelope[1][0] = PosSep(stp1.Pos, stp2.Pos);
    ss.Envelope[1][1] = tcc.showerTag[5] + tcc.showerTag[4] * stp2.DeltaRMS;
    // third and fourth are reflections of the first and second
    ss.Envelope[2][0] = ss.Envelope[1][0];
    ss.Envelope[2][1] = -ss.Envelope[1][1];
    ss.Envelope[3][0] = ss.Envelope[0][0];
    ss.Envelope[3][1] = -ss.Envelope[0][1];

    float length = ss.Envelope[1][0] - ss.Envelope[0][0];
    float width = ss.Envelope[0][1] + ss.Envelope[1][1];
    ss.EnvelopeArea = length * width;

    // Rotate into the stp1 coordinate system
    float cs = cos(stp1.Ang);
    float sn = sin(stp1.Ang);
    for (auto& vtx : ss.Envelope) {
      // Rotate along the stj shower axis
      float pos0 = cs * vtx[0] - sn * vtx[1];
      float pos1 = sn * vtx[0] + cs * vtx[1];
      // translate
      vtx[0] = pos0 + stp1.Pos[0];
      vtx[1] = pos1 + stp1.Pos[1];
    } // vtx
    // Find the charge density inside the envelope
    ss.ChgDensity = (stp0.Chg + stp1.Chg + stp2.Chg) / ss.EnvelopeArea;
    if (prt) {
      mf::LogVerbatim myprt("TC");
      myprt << fcnLabel << " 2S" << ss.ID << " Envelope";
      for (auto& vtx : ss.Envelope)
        myprt << " " << (int)vtx[0] << ":" << (int)(vtx[1] / tcc.unitsPerTick);
      myprt << " Area " << (int)ss.EnvelopeArea;
      myprt << " ChgDensity " << ss.ChgDensity;
    }
    // This is the last function used to update a shower
    ss.NeedsUpdate = false;
  } // DefineEnvelope

  bool AddTjsInsideEnvelope(std::string inFcnLabel, TCSlice& slc, ShowerStruct& ss, bool prt)
  {
    // This function adds Tjs to the shower. It updates the shower parameters.

    if (ss.Envelope.empty()) return false;
    if (ss.ID == 0) return false;
    if (ss.TjIDs.empty()) return false;

    std::string fcnLabel = inFcnLabel + ".ATIE";

    if (prt) mf::LogVerbatim("TC") << fcnLabel << " Checking 2S" << ss.ID;

    std::vector<int> tmp(1);
    unsigned short nadd = 0;
    for (auto& tj : slc.tjs) {
      if (tj.CTP != ss.CTP) continue;
      if (tj.AlgMod[kKilled]) continue;
      if (tj.SSID > 0) continue;
      if (tj.AlgMod[kShowerTj]) continue;
      // See if this Tjs is attached to a neutrino vertex.
      if (tj.ParentID == 0) continue;
      int neutPrimTj = NeutrinoPrimaryTjID(slc, tj);
      if (neutPrimTj > 0 && neutPrimTj != tj.ID) {
        // The Tj is connected to a primary Tj that is associated with a neutrino primary.
        // Don't allow tjs to be added to the shower that are not connected to this neutrino primary (if
        // one exists)
        if (ss.ParentID > 0 && neutPrimTj != ss.ParentID) continue;
      } // neutrino primary tj
      // This shouldn't be necessary but ensure that the Tj ID appears only once in ss.TjIDs
      if (std::find(ss.TjIDs.begin(), ss.TjIDs.end(), tj.ID) != ss.TjIDs.end()) continue;
      // check consistency
      tmp[0] = tj.ID;
      if (DontCluster(slc, tmp, ss.TjIDs)) continue;
      // See if both ends are outside the envelope
      bool end0Inside = PointInsideEnvelope(tj.Pts[tj.EndPt[0]].Pos, ss.Envelope);
      bool end1Inside = PointInsideEnvelope(tj.Pts[tj.EndPt[1]].Pos, ss.Envelope);
      if (!end0Inside && !end1Inside) continue;
      if (end0Inside && end1Inside) {
        // TODO: See if the Tj direction is compatible with the shower?
        if (AddTj(fcnLabel, slc, tj.ID, ss, false, prt)) ++nadd;
        ++nadd;
        continue;
      } // both ends inside
      // Require high momentum Tjs be aligned with the shower axis
      // TODO also require high momentum Tjs close to the shower axis?

      if (tj.MCSMom > 200) {
        float tjAngle = tj.Pts[tj.EndPt[0]].Ang;
        float dangPull = std::abs(tjAngle - ss.AngleErr) / ss.AngleErr;
        if (prt)
          mf::LogVerbatim("TC") << fcnLabel << " high MCSMom " << tj.MCSMom << " dangPull "
                                << dangPull;
        if (dangPull > 2) continue;
      } // high momentum
      if (AddTj(fcnLabel, slc, tj.ID, ss, false, prt)) { ++nadd; }
      else {
        if (prt) mf::LogVerbatim("TC") << fcnLabel << " AddTj failed to add T" << tj.ID;
      }
    } // tj

    if (nadd > 0) {
      if (prt) mf::LogVerbatim("TC") << fcnLabel << " Added " << nadd << " trajectories ";
      ss.NeedsUpdate = true;
      UpdateShower(fcnLabel, slc, ss, prt);
      return true;
    }
    else {
      if (prt) mf::LogVerbatim("TC") << fcnLabel << " No new trajectories added to envelope ";
      ss.NeedsUpdate = false;
      return false;
    }

  } // AddTjsInsideEnvelope

  bool AddLooseHits(TCSlice& slc, int cotID, bool prt)
  {
    // Add hits that are inside the envelope to the shower if they are loose, i.e. not
    // used by any trajectory. This function returns true if the set of hits is different than
    // the current set. The calling function should update the shower if this is the case.

    ShowerStruct& ss = slc.cots[cotID - 1];
    if (ss.Envelope.empty()) return false;
    if (ss.ID == 0) return false;
    if (ss.TjIDs.empty()) return false;

    geo::PlaneID planeID = DecodeCTP(ss.CTP);
    unsigned short ipl = planeID.Plane;

    Trajectory& stj = slc.tjs[ss.ShowerTjID - 1];
    TrajPoint& stp0 = stj.Pts[0];
    // start a list of new hits
    std::vector<unsigned int> newHits;

    // look for hits inside the envelope. Find the range of wires that spans the envelope
    float fLoWire = 1E6;
    float fHiWire = 0;
    // and the range of ticks
    float loTick = 1E6;
    float hiTick = 0;
    for (auto& vtx : ss.Envelope) {
      if (vtx[0] < fLoWire) fLoWire = vtx[0];
      if (vtx[0] > fHiWire) fHiWire = vtx[0];
      if (vtx[1] < loTick) loTick = vtx[1];
      if (vtx[1] > hiTick) hiTick = vtx[1];
    } // vtx
    loTick /= tcc.unitsPerTick;
    hiTick /= tcc.unitsPerTick;
    unsigned int loWire = std::nearbyint(fLoWire);
    unsigned int hiWire = std::nearbyint(fHiWire) + 1;
    if (hiWire > slc.lastWire[ipl] - 1) hiWire = slc.lastWire[ipl] - 1;
    std::array<float, 2> point;
    for (unsigned int wire = loWire; wire < hiWire; ++wire) {
      // skip bad wires or no hits on the wire
      if (slc.wireHitRange[ipl][wire].first == UINT_MAX) continue;
      unsigned int firstHit = slc.wireHitRange[ipl][wire].first;
      unsigned int lastHit = slc.wireHitRange[ipl][wire].second;
      for (unsigned int iht = firstHit; iht < lastHit; ++iht) {
        // used in a trajectory?
        if (slc.slHits[iht].InTraj != 0) continue;
        auto& hit = (*evt.allHits)[slc.slHits[iht].allHitsIndex];
        // inside the tick range?
        if (hit.PeakTime() < loTick) continue;
        // Note that hits are sorted by increasing time so we can break here
        if (hit.PeakTime() > hiTick) break;
        // see if this hit is inside the envelope
        point[0] = hit.WireID().Wire;
        point[1] = hit.PeakTime() * tcc.unitsPerTick;
        if (!PointInsideEnvelope(point, ss.Envelope)) continue;
        newHits.push_back(iht);
      } // iht
    }   // wire

    // no new hits and no old hits. Nothing to do
    if (newHits.empty()) {
      if (prt) mf::LogVerbatim("TC") << "ALH: No new loose hits found";
      return false;
    }

    // Update
    stp0.Hits.insert(stp0.Hits.end(), newHits.begin(), newHits.end());
    for (auto& iht : newHits)
      slc.slHits[iht].InTraj = stj.ID;

    if (prt)
      mf::LogVerbatim("TC") << "ALH: Added " << stp0.Hits.size() << " hits to stj " << stj.ID;
    return true;

  } // AddLooseHits

  void FindStartChg(std::string inFcnLabel, TCSlice& slc, int cotID, bool prt)
  {
    // Finds the charge at the start of a shower and puts it in AveChg of the first
    // point of the shower Tj. This is only done when there is no parent.
    if (cotID > (int)slc.cots.size()) return;

    ShowerStruct& ss = slc.cots[cotID - 1];
    if (ss.ID == 0) return;
    if (ss.TjIDs.empty()) return;
    if (ss.ShowerTjID == 0) return;
    if (ss.ParentID > 0) return;
    auto& stp0 = slc.tjs[ss.ShowerTjID - 1].Pts[0];

    std::string fcnLabel = inFcnLabel + ".FSC";

    stp0.AveChg = 0;

    if (ss.AspectRatio > tcc.showerTag[10] || ss.DirectionFOM > tcc.showerTag[9]) {
      if (prt)
        mf::LogVerbatim("TC") << fcnLabel << " Not possible due to poor AspectRatio "
                              << ss.AspectRatio << " or ss.DirectionFOM " << ss.DirectionFOM;
      return;
    }

    // Create and fill a vector of the charge at the beginning of the shower in 1 WSE bins
    auto schg = StartChgVec(slc, cotID);
    if (schg.empty()) return;

    // Look for two consecutive charge entries. Use the second one
    // for the initial guess at the charge
    unsigned short startPt = USHRT_MAX;
    float chg = 0;
    for (unsigned short ii = 0; ii < schg.size() - 1; ++ii) {
      if (schg[ii] > 0 && schg[ii + 1] > 0) {
        startPt = ii + 1;
        chg = schg[ii + 1];
        break;
      }
    }
    if (startPt == USHRT_MAX) return;

    // get an initial average and rms using all the points
    float ave = 0;
    float rms = 0;
    float cnt = 0;
    for (unsigned short ii = startPt; ii < schg.size() - 1; ++ii) {
      ave += schg[ii];
      rms += schg[ii] * schg[ii];
      ++cnt;
    } // ii
    ave /= cnt;
    rms = rms - cnt * ave * ave;
    if (rms < 0) return;
    rms = sqrt(rms / (cnt - 1));

    if (prt) {
      mf::LogVerbatim myprt("TC");
      myprt << fcnLabel << " schg:";
      for (unsigned short ii = 0; ii < 20; ++ii)
        myprt << " " << (int)schg[ii];
      myprt << "\n First guess at the charge " << (int)chg << " average charge of all bins "
            << (int)ave << " rms " << (int)rms;
    }

    // initial guess at the charge rms
    rms = 0.8 * chg;

    unsigned short nBinsAverage = 5;
    double maxChg = 2 * chg;
    for (unsigned short nit = 0; nit < 2; ++nit) {
      double sum = 0;
      double sum2 = 0;
      double cnt = 0;
      for (unsigned short ii = startPt; ii < schg.size() - 1; ++ii) {
        // break if we find 2 consecutive high charge points
        if (schg[ii] > maxChg && schg[ii + 1] > maxChg) break;
        // or two zeros
        if (schg[ii] == 0 && schg[ii + 1] == 0) break;
        if (schg[ii] > maxChg) continue;
        sum += schg[ii];
        sum2 += schg[ii] * schg[ii];
        ++cnt;
        if (cnt == nBinsAverage) break;
      } // ii
      // check for a failure
      if (cnt < 3) {
        if (prt)
          mf::LogVerbatim("TC") << fcnLabel << " nit " << nit << " cnt " << cnt
                                << " is too low. sum " << (int)sum << " maxChg " << (int)maxChg;
        // try to recover. Pick the next point
        ++startPt;
        chg = schg[startPt];
        maxChg = 2 * chg;
        continue;
      }
      // convert sum to the average charge
      chg = sum / cnt;
      double arg = sum2 - cnt * chg * chg;
      if (arg < 0) break;
      rms = sqrt(arg / (cnt - 1));
      // don't allow the rms to get crazy
      double maxrms = 0.5 * sum;
      if (rms > maxrms) rms = maxrms;
      maxChg = chg + 2 * rms;
      if (prt)
        mf::LogVerbatim("TC") << fcnLabel << " nit " << nit << " cnt " << cnt << " chg " << (int)chg
                              << " rms " << (int)rms << " maxChg " << (int)maxChg
                              << " nBinsAverage " << nBinsAverage;
      nBinsAverage = 20;
    } // nit

    stp0.AveChg = chg;

    if (prt)
      mf::LogVerbatim("TC") << fcnLabel << " 2S" << cotID << " Starting charge " << (int)stp0.AveChg
                            << " startPt  " << startPt;

  } // FindStartChg

  std::vector<float> StartChgVec(TCSlice& slc, int cotID)
  {
    // Returns a histogram vector of the charge in bins of 1 WSE unit at the start of the shower

    ShowerStruct& ss = slc.cots[cotID - 1];
    constexpr unsigned short nbins = 20;
    std::vector<float> schg(nbins);
    if (ss.ID == 0) return schg;
    if (ss.TjIDs.empty()) return schg;
    TrajPoint& stp1 = slc.tjs[ss.ShowerTjID - 1].Pts[1];

    // move the min along point back by 2 WSE so that most of the charge in the hits in the
    // first point is included in the histogram
    float minAlong = ss.ShPts[0].RotPos[0] - 2;

    float maxTrans = 4;
    // Tighten up on the maximum allowed transverse position if there is a parent
    if (ss.ParentID > 0) maxTrans = 1;
    float cs = cos(-ss.Angle);
    float sn = sin(-ss.Angle);
    std::array<float, 2> chgPos;
    float along, arg;

    for (auto& sspt : ss.ShPts) {
      unsigned short indx = (unsigned short)((sspt.RotPos[0] - minAlong));
      if (indx > nbins - 1) break;
      // Count the charge if it is within a few WSE transverse from the shower axis
      if (std::abs(sspt.RotPos[1]) > maxTrans) continue;
      unsigned int iht = sspt.HitIndex;
      auto& hit = (*evt.allHits)[slc.slHits[iht].allHitsIndex];
      float peakTime = hit.PeakTime();
      float amp = hit.PeakAmplitude();
      float rms = hit.RMS();
      chgPos[0] = hit.WireID().Wire - stp1.Pos[0];
      for (float time = peakTime - 2.5 * rms; time < peakTime + 2.5 * rms; ++time) {
        chgPos[1] = time * tcc.unitsPerTick - stp1.Pos[1];
        along = cs * chgPos[0] - sn * chgPos[1];
        if (along < minAlong) continue;
        indx = (unsigned short)(along - minAlong);
        if (indx > nbins - 1) continue;
        arg = (time - peakTime) / rms;
        schg[indx] += amp * exp(-0.5 * arg * arg);
      } // time
    }   // sspt

    return schg;
  } // StartChgVec

  void DumpShowerPts(TCSlice& slc, int cotID)
  {
    // Print the shower points to the screen. The user should probably pipe the output to a text file
    // then grep this file for the character string PTS which is piped to a text file which can then be
    // imported into Excel, etc
    // Finds the charge at the start of a shower
    if (cotID > (int)slc.cots.size()) return;

    ShowerStruct& ss = slc.cots[cotID - 1];
    if (ss.ID == 0) return;
    if (ss.TjIDs.empty()) return;
    std::cout << "PTS Pos0  Pos1   RPos0 RPos1 Chg TID\n";
    for (auto& pt : ss.ShPts) {
      std::cout << "PTS " << std::fixed << std::setprecision(1) << pt.Pos[0] << " " << pt.Pos[1]
                << " " << pt.RotPos[0] << " " << pt.RotPos[1];
      std::cout << " " << (int)pt.Chg << " " << pt.TID;
      std::cout << "\n";
    }

  } // DumpShowerPts

  bool TransferTjHits(TCSlice& slc, bool prt)
  {
    // Transfer InShower hits in all TPCs and planes to the shower Tjs

    bool newShowers = false;
    for (auto& ss : slc.cots) {
      if (ss.ID == 0) continue;
      if (ss.ShowerTjID == 0) continue;
      // Tp 1 of stj will get all of the shower hits
      Trajectory& stj = slc.tjs[ss.ShowerTjID - 1];
      if (!stj.Pts[1].Hits.empty()) {
        std::cout << "TTjH: ShowerTj T" << stj.ID << " already has " << stj.Pts[1].Hits.size()
                  << " hits\n";
        continue;
      }
      // Note that UseHit is not used since the size is limited to 16
      for (auto& tjID : ss.TjIDs) {
        unsigned short itj = tjID - 1;
        if (slc.tjs[itj].AlgMod[kShowerTj]) {
          std::cout << "TTjH: Coding error. T" << tjID << " is a ShowerTj but is in TjIDs\n";
          continue;
        }
        if (slc.tjs[itj].SSID <= 0) {
          std::cout << "TTjH: Coding error. Trying to transfer T" << tjID
                    << " hits but it isn't an InShower Tj\n";
          continue;
        }
        auto thits = PutTrajHitsInVector(slc.tjs[itj], kUsedHits);
        // associate all hits with the charge center TP
        stj.Pts[1].Hits.insert(stj.Pts[1].Hits.end(), thits.begin(), thits.end());
        // kill Tjs that are in showers
        slc.tjs[itj].AlgMod[kKilled] = true;
      } //  tjID
      // re-assign the hit -> stj association
      for (auto& iht : stj.Pts[1].Hits)
        slc.slHits[iht].InTraj = stj.ID;
      newShowers = true;
    } // ss

    if (prt) mf::LogVerbatim("TC") << "TTJH: success? " << newShowers;
    return newShowers;
  } // TransferTjHits

  int GetCotID(TCSlice& slc, int ShowerTjID)
  {
    for (unsigned short ii = 0; ii < slc.cots.size(); ++ii) {
      if (ShowerTjID == slc.cots[ii].ShowerTjID) return ii + 1;
    } // iii
    return 0;

  } // GetCotID

  double ShowerEnergy(const ShowerStruct3D& ss3)
  {
    if (ss3.ID == 0) return 0;
    if (ss3.Energy.empty()) return 0;
    double ave = 0;
    for (auto e : ss3.Energy) {
      ave += e;
    } // e
    ave /= ss3.Energy.size();
    return ave;
  } // ShowerEnergy

  float ShowerEnergy(TCSlice& slc, const std::vector<int> tjIDs)
  {
    // Calculate energy using the total charge of all hits in each tj in the shower
    if (tjIDs.empty()) return 0;
    float sum = 0;
    for (auto tid : tjIDs) {
      auto& tj = slc.tjs[tid - 1];
      sum += tj.TotChg;
    } // tid
    return ChgToMeV(sum);
  } // ShowerEnergy

  float ChgToMeV(float chg)
  {
    // Conversion from shower charge to energy in MeV. The calibration factor
    // was found by processing 500 pizero events with StudyPiZeros using StudyMode
    return 0.012 * chg;
  }

  bool StoreShower(std::string inFcnLabel, TCSlice& slc, ShowerStruct3D& ss3)
  {
    // Store a 3D shower. This function sets the 3S -> 2S assns using CotIDs and ensures
    // that the 2S -> 3S assns are OK.

    std::string fcnLabel = inFcnLabel + ".S3S";
    if (ss3.ID <= 0) {
      std::cout << fcnLabel << " Invalid ID";
      return false;
    }
    if (ss3.CotIDs.size() < 2) {
      std::cout << fcnLabel << " not enough CotIDs";
      return false;
    }

    // check the 2S -> 3S assns
    for (auto& ss : slc.cots) {
      if (ss.ID == 0) continue;
      if (ss.SS3ID == ss3.ID &&
          std::find(ss3.CotIDs.begin(), ss3.CotIDs.end(), ss.ID) == ss3.CotIDs.end()) {
        std::cout << fcnLabel << " Bad assn: 2S" << ss.ID << " -> 3S" << ss3.ID
                  << " but it's not inCotIDs.\n";
        return false;
      }
    } // ss

    // check the 3S -> 2S assns
    for (auto cid : ss3.CotIDs) {
      if (cid <= 0 || cid > (int)slc.cots.size()) return false;
      auto& ss = slc.cots[cid - 1];
      if (ss.SS3ID > 0 && ss.SS3ID != ss3.ID) {
        std::cout << fcnLabel << " Bad assn: 3S" << ss3.ID << " -> 2S" << cid << " but 2S -> 3S"
                  << ss.SS3ID << "\n";
        return false;
      }
    } // cid

    // set the 2S -> 3S assns
    for (auto cid : ss3.CotIDs)
      slc.cots[cid - 1].SS3ID = ss3.ID;

    ++evt.global3S_UID;
    ss3.UID = evt.global3S_UID;

    slc.showers.push_back(ss3);
    return true;

  } // StoreShower

  bool StoreShower(std::string inFcnLabel, TCSlice& slc, ShowerStruct& ss)
  {
    // Store a ShowerStruct
    std::string fcnLabel = inFcnLabel + ".S2S";
    if (ss.ID <= 0) {
      std::cout << fcnLabel << " Invalid ID";
      return false;
    }
    if (ss.TjIDs.empty()) {
      std::cout << fcnLabel << " Fail: No TjIDs in 2S" << ss.ID << "\n";
      return false;
    }
    if (ss.ParentID > 0) {
      if (ss.ParentID > (int)slc.tjs.size()) {
        std::cout << fcnLabel << " Fail: 2S" << ss.ID << " has an invalid ParentID T" << ss.ParentID
                  << "\n";
        return false;
      }
      if (std::find(ss.TjIDs.begin(), ss.TjIDs.end(), ss.ParentID) != ss.TjIDs.end()) {
        std::cout << fcnLabel << " Fail: 2S" << ss.ID << " ParentID is not in TjIDs.\n";
        return false;
      }
    } // ss.ParentID > 0

    // check the ID
    if (ss.ID != (int)slc.cots.size() + 1) {
      std::cout << fcnLabel << " Correcting the ID 2S" << ss.ID << " -> 2S" << slc.cots.size() + 1;
      ss.ID = slc.cots.size() + 1;
    }

    // set the tj shower bits
    for (auto& tjID : ss.TjIDs) {
      Trajectory& tj = slc.tjs[tjID - 1];
      tj.SSID = ss.ID;
      tj.AlgMod[kShwrParent] = false;
      if (tj.ID == ss.ParentID) tj.AlgMod[kShwrParent] = true;
    } // tjID

    ++evt.global2S_UID;
    ss.UID = evt.global2S_UID;

    slc.cots.push_back(ss);
    return true;

  } // StoreShower

  ShowerStruct3D CreateSS3(TCSlice& slc)
  {
    // create a 3D shower and size the vectors that are indexed by plane

    ShowerStruct3D ss3;
    ss3.TPCID = slc.TPCID;
    ss3.ID = slc.showers.size() + 1;
    ss3.Energy.resize(slc.nPlanes);
    ss3.EnergyErr.resize(slc.nPlanes);
    ss3.MIPEnergy.resize(slc.nPlanes);
    ss3.MIPEnergyErr.resize(slc.nPlanes);
    ss3.dEdx.resize(slc.nPlanes);
    ss3.dEdxErr.resize(slc.nPlanes);

    return ss3;

  } // CreateSS3

  ShowerStruct CreateSS(TCSlice& slc, const std::vector<int>& tjl)
  {
    // Create a shower and shower Tj using Tjs in the list. If tjl is empty a
    // MC cheat shower is created inCTP. Note that inCTP is only used if tjl is empty.
    // A companion shower tj is created and stored but the ShowerStruct is not.
    ShowerStruct ss;

    // Create the shower tj
    Trajectory stj;
    stj.CTP = slc.tjs[tjl[0] - 1].CTP;

    // with three points
    stj.Pts.resize(3);
    for (auto& stp : stj.Pts) {
      stp.CTP = stj.CTP;
      // set all UseHit bits true so we don't get confused
      stp.UseHit.set();
    }
    stj.EndPt[0] = 0;
    stj.EndPt[1] = 2;
    stj.ID = slc.tjs.size() + 1;
    // Declare that stj is a shower Tj
    stj.AlgMod[kShowerTj] = true;
    stj.PDGCode = 1111;
    slc.tjs.push_back(stj);
    // define the ss
    ss.ID = slc.cots.size() + 1;
    ss.CTP = stj.CTP;
    // assign all TJ IDs to this ShowerStruct
    ss.TjIDs = tjl;
    // declare them to be InShower
    for (auto tjid : tjl) {
      auto& tj = slc.tjs[tjid - 1];
      if (tj.CTP != stj.CTP) {
        ss.ID = 0;
        return ss;
      }
      tj.SSID = ss.ID;
    } // tjid
    ss.ShowerTjID = stj.ID;
    ss.Envelope.resize(4);
    return ss;

  } // CreateSS

  bool ChkAssns(std::string inFcnLabel, TCSlice& slc)
  {
    // check tj - ss assns

    std::string fcnLabel = inFcnLabel + ".ChkAssns";
    for (auto& ss : slc.cots) {
      if (ss.ID == 0) continue;
      for (auto tid : ss.TjIDs) {
        auto& tj = slc.tjs[tid - 1];
        if (tj.SSID != ss.ID) {
          std::cout << fcnLabel << " ***** Error: 2S" << ss.ID << " -> TjIDs T" << tid
                    << " != tj.SSID 2S" << tj.SSID << "\n";
          return false;
        }
      } // tid
      // check 2S -> 3S
      if (ss.SS3ID > 0 && ss.SS3ID <= (int)slc.showers.size()) {
        auto& ss3 = slc.showers[ss.SS3ID - 1];
        if (std::find(ss3.CotIDs.begin(), ss3.CotIDs.end(), ss.ID) == ss3.CotIDs.end()) {
          std::cout << fcnLabel << " ***** Error: 2S" << ss.ID << " -> 3S" << ss.SS3ID
                    << " but the shower says no\n";
          return false;
        }
      } // ss.SS3ID > 0
    }   // ss
    for (auto& tj : slc.tjs) {
      if (tj.AlgMod[kKilled]) continue;
      if (tj.SSID < 0) {
        std::cout << fcnLabel << " ***** Error: T" << tj.ID << " tj.SSID is fubar\n";
        tj.SSID = 0;
        return false;
      }
      if (tj.SSID == 0) continue;
      auto& ss = slc.cots[tj.SSID - 1];
      if (std::find(ss.TjIDs.begin(), ss.TjIDs.end(), tj.ID) != ss.TjIDs.end()) continue;
      std::cout << fcnLabel << " ***** Error: T" << tj.ID << " tj.SSID = 2S" << tj.SSID
                << " but the shower says no\n";
      return false;
    } // tj

    for (auto& ss3 : slc.showers) {
      if (ss3.ID == 0) continue;
      for (auto cid : ss3.CotIDs) {
        auto& ss = slc.cots[cid - 1];
        if (ss.SS3ID != ss3.ID) {
          std::cout << fcnLabel << " ***** Error: 3S" << ss3.ID << " -> 2S" << cid
                    << " but it thinks it belongs to 3S" << ss.SS3ID << "\n";
          return false;
        }
      } // cid
    }   // ss3
    return true;
  } // ChkAssns

  void PrintShowers(detinfo::DetectorPropertiesData const& detProp,
                    std::string fcnLabel,
                    TCSlice const& slc)
  {
    if (slc.showers.empty()) return;
    mf::LogVerbatim myprt("TC");
    myprt << fcnLabel << " 3D showers \n";
    for (auto& ss3 : slc.showers) {
      myprt << fcnLabel << " 3S" << ss3.ID << " 3V" << ss3.Vx3ID;
      myprt << " parentID " << ss3.ParentID;
      myprt << " ChgPos" << std::fixed;
      for (unsigned short xyz = 0; xyz < 3; ++xyz)
        myprt << " " << std::setprecision(0) << ss3.ChgPos[xyz];
      myprt << " Dir";
      for (unsigned short xyz = 0; xyz < 3; ++xyz)
        myprt << " " << std::setprecision(2) << ss3.Dir[xyz];
      myprt << " posInPlane";
      std::vector<float> projInPlane(slc.nPlanes);
      for (unsigned short plane = 0; plane < slc.nPlanes; ++plane) {
        CTP_t inCTP = EncodeCTP(ss3.TPCID.Cryostat, ss3.TPCID.TPC, plane);
        auto tp = MakeBareTP(detProp, ss3.ChgPos, ss3.Dir, inCTP);
        myprt << " " << PrintPos(tp.Pos);
        projInPlane[plane] = tp.Delta;
      } // plane
      myprt << " projInPlane";
      for (unsigned short plane = 0; plane < slc.nPlanes; ++plane) {
        myprt << " " << std::fixed << std::setprecision(2) << projInPlane[plane];
      } // plane
      for (auto cid : ss3.CotIDs) {
        auto& ss = slc.cots[cid - 1];
        myprt << "\n  2S" << ss.ID;
        auto& stj = slc.tjs[ss.ShowerTjID - 1];
        myprt << " ST" << stj.ID;
        myprt << " " << PrintPos(stj.Pts[stj.EndPt[0]].Pos) << " - "
              << PrintPos(stj.Pts[stj.EndPt[1]].Pos);
      } // ci
      if (ss3.NeedsUpdate) myprt << " *** Needs update";
      myprt << "\n";
    } // sss3
  }   // PrintShowers

  void Print2DShowers(std::string someText,
                      TCSlice const& slc,
                      CTP_t inCTP,
                      bool printKilledShowers)
  {
    // Prints a one-line summary of 2D showers
    if (slc.cots.empty()) return;

    mf::LogVerbatim myprt("TC");

    // see how many lines were are going to print
    bool printAllCTP = (inCTP == USHRT_MAX);
    if (!printAllCTP) {
      unsigned short nlines = 0;
      for (const auto& ss : slc.cots) {
        if (!printAllCTP && ss.CTP != inCTP) continue;
        if (!printKilledShowers && ss.ID == 0) continue;
        ++nlines;
      } // ss
      if (nlines == 0) {
        myprt << someText << " Print2DShowers: Nothing to print";
        return;
      }
    } // !printAllCTP

    bool printHeader = true;
    bool printExtras = false;
    for (unsigned short ict = 0; ict < slc.cots.size(); ++ict) {
      const auto& ss = slc.cots[ict];
      if (!printAllCTP && ss.CTP != inCTP) continue;
      if (!printKilledShowers && ss.ID == 0) continue;
      PrintShower(someText, slc, ss, printHeader, printExtras);
      printHeader = false;
    } // ss
    // List of Tjs
    for (unsigned short ict = 0; ict < slc.cots.size(); ++ict) {
      const auto& ss = slc.cots[ict];
      if (!printAllCTP && ss.CTP != inCTP) continue;
      if (!printKilledShowers && ss.ID == 0) continue;
      myprt << someText << std::fixed;
      std::string sid = "2S" + std::to_string(ss.ID);
      myprt << std::setw(5) << sid;
      myprt << " Tjs";
      for (auto id : ss.TjIDs)
        myprt << " T" << id;
      myprt << "\n";
    } // ict
    // Print the envelopes
    for (unsigned short ict = 0; ict < slc.cots.size(); ++ict) {
      const auto& ss = slc.cots[ict];
      if (!printAllCTP && ss.CTP != inCTP) continue;
      if (!printKilledShowers && ss.ID == 0) continue;
      myprt << someText << std::fixed;
      std::string sid = "2S" + std::to_string(ss.ID);
      myprt << std::setw(5) << sid;
      myprt << " Envelope";
      for (auto& vtx : ss.Envelope)
        myprt << " " << (int)vtx[0] << ":" << (int)(vtx[1] / tcc.unitsPerTick);
      myprt << "\n";
    } // ict
    // List of nearby Tjs
    for (unsigned short ict = 0; ict < slc.cots.size(); ++ict) {
      const auto& ss = slc.cots[ict];
      if (!printAllCTP && ss.CTP != inCTP) continue;
      if (!printKilledShowers && ss.ID == 0) continue;
      myprt << someText << std::fixed;
      std::string sid = "2S" + std::to_string(ss.ID);
      myprt << std::setw(5) << sid;
      myprt << " Nearby";
      for (auto id : ss.NearTjIDs)
        myprt << " T" << id;
      myprt << "\n";
    } // ict
    // don't cluster list
    myprt << "DontCluster";
    for (auto& dc : slc.dontCluster) {
      if (dc.TjIDs[0] > 0) myprt << " T" << dc.TjIDs[0] << "-T" << dc.TjIDs[1];
    } // dc
    myprt << "\nDontCluster";
    for (unsigned short ict = 0; ict < slc.cots.size(); ++ict) {
      const auto& iss = slc.cots[ict];
      if (iss.ID == 0) continue;
      for (unsigned short jct = ict + 1; jct < slc.cots.size(); ++jct) {
        const auto& jss = slc.cots[jct];
        if (jss.ID == 0) continue;
        if (DontCluster(slc, iss.TjIDs, jss.TjIDs)) myprt << " 2S" << iss.ID << "-2S" << jss.ID;
      } // jct
    }   // ict
  }     // Print2DShowers

  void PrintShower(std::string someText,
                   TCSlice const& slc,
                   const ShowerStruct& ss,
                   bool printHeader,
                   bool printExtras)
  {
    // print a single shower and a header (optional) and the extra variables like TjIDs, envelope, etc
    mf::LogVerbatim myprt("TC");

    if (printHeader) {
      myprt << someText
            << "   ID   CTP  ParID ParFOM TruParID Energy nTjs  dFOM AspRat  stj  vx0 __Pos0___ "
               "Chg(k) dRMS __Pos1___ Chg(k) dRMS __Pos2___ Chg(k) dRMS Angle SS3ID PFPID\n";
    } // printHeader

    myprt << someText << std::fixed;
    std::string sid = "2S" + std::to_string(ss.ID);
    myprt << std::setw(5) << sid;
    myprt << std::setw(6) << ss.CTP;
    sid = "NA";
    if (ss.ParentID > 0) sid = "T" + std::to_string(ss.ParentID);
    myprt << std::setw(7) << sid;
    myprt << std::setw(7) << std::setprecision(2) << ss.ParentFOM;
    myprt << std::setw(9) << ss.TruParentID;
    myprt << std::setw(7) << (int)ss.Energy;
    myprt << std::setw(5) << ss.TjIDs.size();
    myprt << std::setw(6) << std::setprecision(2) << ss.DirectionFOM;
    myprt << std::setw(7) << std::setprecision(2) << ss.AspectRatio;
    const auto& stj = slc.tjs[ss.ShowerTjID - 1];
    std::string tid = "T" + std::to_string(stj.ID);
    myprt << std::setw(5) << tid;
    std::string vid = "NA";
    if (stj.VtxID[0] > 0) vid = "2V" + std::to_string(stj.VtxID[0]);
    myprt << std::setw(5) << vid;
    for (auto& spt : stj.Pts) {
      myprt << std::setw(10) << PrintPos(spt.Pos);
      myprt << std::setw(7) << std::fixed << std::setprecision(1) << spt.Chg / 1000;
      //        myprt<<std::setw(5)<<spt.NTPsFit;
      myprt << std::setw(5) << std::setprecision(1) << spt.DeltaRMS;
    } // spt
    myprt << std::setw(6) << std::setprecision(2) << stj.Pts[1].Ang;
    std::string sss = "NA";
    if (ss.SS3ID > 0) sss = "3S" + std::to_string(ss.SS3ID);
    myprt << std::setw(6) << sss;
    if (ss.SS3ID > 0 && ss.SS3ID < (int)slc.showers.size()) {
      auto& ss3 = slc.showers[ss.SS3ID - 1];
      if (ss3.PFPIndex < slc.pfps.size()) {
        std::string pid = "P" + std::to_string(ss3.PFPIndex + 1);
        myprt << std::setw(6) << pid;
      }
      else {
        myprt << std::setw(6) << "NA";
      }
    }
    else {
      myprt << std::setw(6) << "NA";
    }
    if (ss.NeedsUpdate) myprt << " *** Needs update";

    if (!printExtras) return;
    myprt << "\n";

    myprt << someText << std::fixed;
    sid = "2S" + std::to_string(ss.ID);
    myprt << std::setw(5) << sid;
    myprt << " Tjs";
    for (auto id : ss.TjIDs)
      myprt << " T" << id;
    myprt << "\n";
    myprt << someText << std::fixed;
    sid = "2S" + std::to_string(ss.ID);
    myprt << std::setw(5) << sid;
    myprt << " Envelope";
    for (auto& vtx : ss.Envelope)
      myprt << " " << (int)vtx[0] << ":" << (int)(vtx[1] / tcc.unitsPerTick);
    myprt << "\n";
    myprt << someText << std::fixed;
    sid = "2S" + std::to_string(ss.ID);
    myprt << std::setw(5) << sid;
    myprt << " Nearby";
    for (auto id : ss.NearTjIDs)
      myprt << " T" << id;

  } // PrintShower

} // namespace tca