util::NormalDistribution Class Reference

#include "PIDAAlg.h"

Public Member Functions
	NormalDistribution ()
	NormalDistribution (float, float)
float	getValue (float)

Private Attributes
float	fStepSize
float	fMaxSigma
std::vector< float >	fValues

Detailed Description

Definition at line 30 of file PIDAAlg.h.

Constructor & Destructor Documentation

util::NormalDistribution::NormalDistribution ( )

inline

Definition at line 33 of file PIDAAlg.h.

{}

util::NormalDistribution::NormalDistribution	(	float	max_sigma,
		float	step_size
	)

Definition at line 352 of file PIDAAlg.cxx.

{

  if (step_size == 0) throw "util::NormalDistribution --- Cannot have zero step size!";

  const size_t vector_size = (size_t)(max_sigma / step_size);
  fValues.resize(vector_size);

  const float AMPLITUDE = 1. / std::sqrt(2 * M_PI);

  float integral = 0;
  for (size_t i_step = 0; i_step < vector_size; i_step++) {
    float diff = i_step * step_size;
    fValues[i_step] = AMPLITUDE * std::exp(-0.5 * diff * diff);
    integral += fValues[i_step];
  }

  for (size_t i_step = 0; i_step < vector_size; i_step++)
    fValues[i_step] /= (integral * 2);

  fStepSize = step_size;
  fMaxSigma = fStepSize * vector_size;
}

Member Function Documentation

float util::NormalDistribution::getValue

(

float

x

)

Definition at line 376 of file PIDAAlg.cxx.

References util::abs().

Referenced by pid::PIDAAlg::createKDE().

{

  x = std::abs(x);
  if (x > fMaxSigma) return 0;

  size_t bin_low = x / fStepSize;
  float remainder = (x - (bin_low * fStepSize)) / fStepSize;

  return fValues[bin_low] * (1 - remainder) + remainder * fValues[bin_low + 1];
}

Member Data Documentation

float util::NormalDistribution::fMaxSigma

private

Definition at line 40 of file PIDAAlg.h.

float util::NormalDistribution::fStepSize

private

Definition at line 39 of file PIDAAlg.h.

std::vector<float> util::NormalDistribution::fValues

private

Definition at line 41 of file PIDAAlg.h.

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The documentation for this class was generated from the following files:

• larana/v09_15_05/source/larana/ParticleIdentification/PIDAAlg.h
• larana/v09_15_05/source/larana/ParticleIdentification/PIDAAlg.cxx