CDCDedxHadSat Class Reference

Class to hold the hadron saturation functions. More...

#include <CDCDedxHadSat.h>

Collaboration diagram for CDCDedxHadSat:

Public Member Functions
void	setParameters ()
	set the parameters
void	setParameters (std::string infile)
	set the parameters from file
double	D2I (double cosTheta, double D) const
	hadron saturation parameterization part 1
double	I2D (double cosTheta, double I) const
	hadron saturation parameterization part 2
double	D2I (double cosTheta, double D, double alpha, double gamma, double delta, double power, double ratio) const
	hadron saturation parameterization part 1
double	I2D (double cosTheta, double I, double alpha, double gamma, double delta, double power, double ratio) const
	hadron saturation parameterization part 2

Private Attributes
double	m_alpha
	the alpha parameter for the hadron saturation correction
double	m_gamma
	the gamma parameter for the hadron saturation correction
double	m_delta
	the delta parameter for the hadron saturation correction
double	m_power
	the power parameter for the hadron saturation correction
double	m_ratio
	the ratio parameter for the hadron saturation correction
DBObjPtr< CDCDedxHadronCor >	m_DBHadronCor
	db object for dE/dx hadron saturation parameters

Detailed Description

Class to hold the hadron saturation functions.

Definition at line 31 of file CDCDedxHadSat.h.

Member Function Documentation

D2I() [1/2]

double D2I	(	double	cosTheta,
		double	D = 1
	)		const

hadron saturation parameterization part 1

Definition at line 48 of file CDCDedxHadSat.cc.

{
 
  double absCosTheta   = fabs(cosTheta);
  double projection    = pow(absCosTheta, m_power) + m_delta;
 
  if (projection == 0) {
    B2WARNING("Something wrong with dE/dx hadron constants!");
    return D;
  }
 
  double chargeDensity = D / projection;
  double numerator     = 1 + m_alpha * chargeDensity;
  double denominator   = 1 + m_gamma * chargeDensity;
  if (denominator == 0) {
    B2WARNING("Something wrong with dE/dx hadron constants!");
    return D;
  }
  double I = D * m_ratio * numerator / denominator;
 
  return I;
}

D2I() [2/2]

double D2I	(	double	cosTheta,
		double	D,
		double	alpha,
		double	gamma,
		double	delta,
		double	power,
		double	ratio
	)		const

hadron saturation parameterization part 1

Definition at line 109 of file CDCDedxHadSat.cc.

{
 
  double absCosTheta   = fabs(cosTheta);
  double projection    = pow(absCosTheta, power) + delta;
  if (projection == 0) {
    B2INFO("\t HadronSaturation: D2I Something wrong with dE/dx hadron constants!");
    return D;
  }
 
  double chargeDensity = D / projection;
  double numerator     = 1 + alpha * chargeDensity;
  double denominator   = 1 + gamma * chargeDensity;
  if (denominator == 0) {
    B2INFO("\t HadronSaturation: D2I Something wrong with dE/dx hadron constants!");
    return D;
  }
 
  double I = D * ratio * numerator / denominator;
 
  return I;
}

I2D() [1/2]

double I2D	(	double	cosTheta,
		double	I = 1
	)		const

hadron saturation parameterization part 2

Definition at line 71 of file CDCDedxHadSat.cc.

{
 
  double absCosTheta = fabs(cosTheta);
  double projection  = pow(absCosTheta, m_power) + m_delta;
 
  if (projection == 0 || m_ratio == 0) {
    B2WARNING("Something wrong with dE/dx hadron constants!");
    return I;
  }
  double a =  m_alpha / projection;
  double b =  1 - m_gamma / projection * (I / m_ratio);
  double c = -1.0 * I / m_ratio;
 
  if (b == 0 && a == 0) {
    B2WARNING("both a and b coefficients for hadron correction are 0");
    return I;
  }
 
  double discr = b * b - 4.0 * a * c;
  if (discr < 0) {
    B2WARNING("negative discriminant; return uncorrected value");
    return I;
  }
 
  double D = (a != 0) ? (-b + sqrt(discr)) / (2.0 * a) : -c / b;
  if (D < 0) {
    B2WARNING("D is less 0! will try another solution");
    D = (a != 0) ? (-b - sqrt(discr)) / (2.0 * a) : -c / b;
    if (D < 0) {
      B2WARNING("D is still less 0! just return uncorrected value");
      return I;
    }
  }
  return D;
}

I2D() [2/2]

double I2D	(	double	cosTheta,
		double	I,
		double	alpha,
		double	gamma,
		double	delta,
		double	power,
		double	ratio
	)		const

hadron saturation parameterization part 2

Definition at line 133 of file CDCDedxHadSat.cc.

{
 
  double absCosTheta = fabs(cosTheta);
  double projection  = pow(absCosTheta, power) + delta;
 
  if (projection == 0 || ratio == 0) {
    B2INFO("\t HadronSaturation: I2D Something wrong with dE/dx hadron constants!");
    return I;
  }
 
  double a =  alpha / projection;
  double b =  1 - (gamma / projection) * (I / ratio);
  double c = -1.0 * I / ratio;
 
  if (b == 0 && a == 0) {
    B2INFO("\t HadronSaturation: both a and b coefficients for hadron correction are 0");
    return I;
  }
 
  double discr = b * b - 4.0 * a * c;
  if (discr < 0) {
    B2INFO("negative discriminant; return uncorrected value");
    return I;
  }
 
  double D = (a != 0) ? (-b + sqrt(discr)) / (2.0 * a) : -c / b;
 
  if (D < 0) {
    B2INFO("D is less 0! will try another solution");
    D = (a != 0) ? (-b - sqrt(discr)) / (2.0 * a) : -c / b;
    if (D < 0) {
      B2INFO("D is still less 0! just return uncorrected value");
      return I;
    }
  }
 
  return D;
}

setParameters() [1/2]

void setParameters

(

)

set the parameters

Definition at line 32 of file CDCDedxHadSat.cc.

{
 
  if (!m_DBHadronCor || m_DBHadronCor->getSize() == 0) {
    B2FATAL("No hadron correction parameters!");
  } else {
    m_alpha = m_DBHadronCor->getHadronPar(0);
    m_gamma = m_DBHadronCor->getHadronPar(1);
    m_delta = m_DBHadronCor->getHadronPar(2);
    m_power = m_DBHadronCor->getHadronPar(3);
    m_ratio = m_DBHadronCor->getHadronPar(4);
  }
}

setParameters() [2/2]

void setParameters

(

std::string

infile

)

set the parameters from file

Definition at line 13 of file CDCDedxHadSat.cc.

{
 
  B2INFO("\n\t Hadron Saturation: Using parameters from file --> " << infile);
 
  std::ifstream fin;
  fin.open(infile.c_str());
 
  if (!fin.good()) B2FATAL("\tWARNING: CANNOT FIND parameters.txt!");
 
  fin >> m_alpha ;
  fin >> m_gamma ;
  fin >> m_delta ;
  fin >> m_power ;
  fin >> m_ratio ;
 
  fin.close();
}

Member Data Documentation

m_alpha

double m_alpha

private

the alpha parameter for the hadron saturation correction

Definition at line 67 of file CDCDedxHadSat.h.

m_DBHadronCor

DBObjPtr<CDCDedxHadronCor> m_DBHadronCor

private

db object for dE/dx hadron saturation parameters

Definition at line 73 of file CDCDedxHadSat.h.

m_delta

double m_delta

private

the delta parameter for the hadron saturation correction

Definition at line 69 of file CDCDedxHadSat.h.

m_gamma

double m_gamma

private

the gamma parameter for the hadron saturation correction

Definition at line 68 of file CDCDedxHadSat.h.

m_power

double m_power

private

the power parameter for the hadron saturation correction

Definition at line 70 of file CDCDedxHadSat.h.

m_ratio

double m_ratio

private

the ratio parameter for the hadron saturation correction

Definition at line 71 of file CDCDedxHadSat.h.

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

• cdc/utilities/include/CDCDedxHadSat.h
• cdc/utilities/src/CDCDedxHadSat.cc