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 26 of file PIDAAlg.h.

Constructor & Destructor Documentation

util::NormalDistribution::NormalDistribution ( )

inline

Definition at line 29 of file PIDAAlg.h.

{}

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

Definition at line 341 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 366 of file PIDAAlg.cxx.

                                             {

  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 36 of file PIDAAlg.h.

float util::NormalDistribution::fStepSize

private

Definition at line 35 of file PIDAAlg.h.

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

private

Definition at line 37 of file PIDAAlg.h.

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

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