G4SimpleIntegration Class Reference

#include <G4SimpleIntegration.hh>

Public Member Functions
G4double	AdaptGaussIntegration (G4double xInitial, G4double xFinal)
	G4SimpleIntegration (const G4SimpleIntegration &)=delete
	G4SimpleIntegration (function pFunction)
	G4SimpleIntegration (function pFunction, G4double pTolerance)
G4double	Gauss (G4double xInitial, G4double xFinal, G4int iterationNumber)
G4double	MidPoint (G4double xInitial, G4double xFinal, G4int iterationNumber)
G4SimpleIntegration &	operator= (const G4SimpleIntegration &)=delete
G4double	Simpson (G4double xInitial, G4double xFinal, G4int iterationNumber)
G4double	Trapezoidal (G4double xInitial, G4double xFinal, G4int iterationNumber)
	~G4SimpleIntegration ()

Protected Member Functions
void	AdaptGauss (G4double xInitial, G4double xFinal, G4double &sum, G4int &depth)
G4double	Gauss (G4double xInitial, G4double xFinal)

Private Attributes
function	fFunction
const G4int	fMaxDepth = 100
G4double	fTolerance = 0.0001

Detailed Description

Definition at line 45 of file G4SimpleIntegration.hh.

Constructor & Destructor Documentation

G4SimpleIntegration() [1/3]

G4SimpleIntegration::G4SimpleIntegration ( function  pFunction )

explicit

Definition at line 34 of file G4SimpleIntegration.cc.

  : fFunction(pFunction)
{}

G4SimpleIntegration() [2/3]

G4SimpleIntegration::G4SimpleIntegration	(	function	pFunction,
		G4double	pTolerance
	)

Definition at line 38 of file G4SimpleIntegration.cc.

  : fFunction(pFunction)
  , fTolerance(pTolerance)
{}

~G4SimpleIntegration()

G4SimpleIntegration::~G4SimpleIntegration

(

)

Definition at line 44 of file G4SimpleIntegration.cc.

{}

G4SimpleIntegration() [3/3]

G4SimpleIntegration::G4SimpleIntegration ( const G4SimpleIntegration &  )

delete

Member Function Documentation

AdaptGauss()

void G4SimpleIntegration::AdaptGauss ( G4double  xInitial, G4double  xFinal, G4double &  sum, G4int &  depth  )

protected

Definition at line 134 of file G4SimpleIntegration.cc.

{
  if(depth > fMaxDepth)
  {
    G4Exception("G4SimpleIntegration::AdaptGauss()", "Error", FatalException,
                "Function varies too rapidly !");
  }
  G4double xMean     = (xInitial + xFinal) / 2.0;
  G4double leftHalf  = Gauss(xInitial, xMean);
  G4double rightHalf = Gauss(xMean, xFinal);
  G4double full      = Gauss(xInitial, xFinal);
  if(std::fabs(leftHalf + rightHalf - full) < fTolerance)
  {
    sum += full;
  }
  else
  {
    ++depth;
    AdaptGauss(xInitial, xMean, sum, depth);
    AdaptGauss(xMean, xFinal, sum, depth);
  }
}

References AdaptGauss(), FatalException, fMaxDepth, fTolerance, G4Exception(), and Gauss().

Referenced by AdaptGauss(), and AdaptGaussIntegration().

AdaptGaussIntegration()

G4double G4SimpleIntegration::AdaptGaussIntegration	(	G4double	xInitial,
		G4double	xFinal
	)

Definition at line 113 of file G4SimpleIntegration.cc.

{
  G4int depth  = 0;
  G4double sum = 0.0;
  AdaptGauss(xInitial, xFinal, sum, depth);
  return sum;
}

References AdaptGauss().

Gauss() [1/2]

G4double G4SimpleIntegration::Gauss ( G4double  xInitial, G4double  xFinal  )

protected

Definition at line 122 of file G4SimpleIntegration.cc.

{
  static const G4double root = 1.0 / std::sqrt(3.0);
 
  G4double xMean = (xInitial + xFinal) / 2.0;
  G4double Step  = (xFinal - xInitial) / 2.0;
  G4double delta = Step * root;
  G4double sum   = (fFunction(xMean + delta) + fFunction(xMean - delta));
 
  return sum * Step;
}

References fFunction.

Gauss() [2/2]

G4double G4SimpleIntegration::Gauss	(	G4double	xInitial,
		G4double	xFinal,
		G4int	iterationNumber
	)

Definition at line 76 of file G4SimpleIntegration.cc.

{
  G4double x                 = 0.;
  static const G4double root = 1.0 / std::sqrt(3.0);
  G4double Step              = (xFinal - xInitial) / (2.0 * iterationNumber);
  G4double delta             = Step * root;
  G4double mean              = 0.0;
  for(G4int i = 0; i < iterationNumber; ++i)
  {
    x = (2 * i + 1) * Step;
    mean += (fFunction(x + delta) + fFunction(x - delta));
  }
  return mean * Step;
}

References fFunction.

Referenced by AdaptGauss().

MidPoint()

G4double G4SimpleIntegration::MidPoint	(	G4double	xInitial,
		G4double	xFinal,
		G4int	iterationNumber
	)

Definition at line 62 of file G4SimpleIntegration.cc.

{
  G4double Step = (xFinal - xInitial) / iterationNumber;
  G4double x    = xInitial + 0.5 * Step;
  G4double mean = fFunction(x);
  for(G4int i = 1; i < iterationNumber; ++i)
  {
    x += Step;
    mean += fFunction(x);
  }
  return mean * Step;
}

References fFunction.

operator=()

G4SimpleIntegration & G4SimpleIntegration::operator= ( const G4SimpleIntegration &  )

delete

Simpson()

G4double G4SimpleIntegration::Simpson	(	G4double	xInitial,
		G4double	xFinal,
		G4int	iterationNumber
	)

Definition at line 92 of file G4SimpleIntegration.cc.

{
  G4double Step  = (xFinal - xInitial) / iterationNumber;
  G4double x     = xInitial;
  G4double xPlus = xInitial + 0.5 * Step;
  G4double mean  = (fFunction(xInitial) + fFunction(xFinal)) * 0.5;
  G4double sum   = fFunction(xPlus);
  for(G4int i = 1; i < iterationNumber; ++i)
  {
    x += Step;
    xPlus += Step;
    mean += fFunction(x);
    sum += fFunction(xPlus);
  }
  mean += 2.0 * sum;
  return mean * Step / 3.0;
}

References fFunction.

Trapezoidal()

G4double G4SimpleIntegration::Trapezoidal	(	G4double	xInitial,
		G4double	xFinal,
		G4int	iterationNumber
	)

Definition at line 48 of file G4SimpleIntegration.cc.

{
  G4double Step = (xFinal - xInitial) / iterationNumber;
  G4double mean = (fFunction(xInitial) + fFunction(xFinal)) * 0.5;
  G4double x    = xInitial;
  for(G4int i = 1; i < iterationNumber; ++i)
  {
    x += Step;
    mean += fFunction(x);
  }
  return mean * Step;
}

References fFunction.

Field Documentation

fFunction

function G4SimpleIntegration::fFunction

private

Definition at line 84 of file G4SimpleIntegration.hh.

Referenced by Gauss(), MidPoint(), Simpson(), and Trapezoidal().

fMaxDepth

const G4int G4SimpleIntegration::fMaxDepth = 100

private

Definition at line 86 of file G4SimpleIntegration.hh.

Referenced by AdaptGauss().

fTolerance

G4double G4SimpleIntegration::fTolerance = 0.0001

private

Definition at line 85 of file G4SimpleIntegration.hh.

Referenced by AdaptGauss().

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

• source/global/HEPNumerics/include/G4SimpleIntegration.hh
• source/global/HEPNumerics/src/G4SimpleIntegration.cc