G4GaussHermiteQ Class Reference

#include <G4GaussHermiteQ.hh>

Inheritance diagram for G4GaussHermiteQ:

Public Member Functions
	G4GaussHermiteQ (function pFunction, G4int nHermite)
G4double	Integral () const
Public Member Functions inherited from G4VGaussianQuadrature
	G4VGaussianQuadrature (function pFunction)
virtual	~G4VGaussianQuadrature ()
G4double	GetAbscissa (G4int index) const
G4double	GetWeight (G4int index) const
G4int	GetNumber () const

Additional Inherited Members
Protected Member Functions inherited from G4VGaussianQuadrature
G4double	GammaLogarithm (G4double xx)
Protected Attributes inherited from G4VGaussianQuadrature
function	fFunction
G4double *	fAbscissa
G4double *	fWeight
G4int	fNumber

Detailed Description

Definition at line 60 of file G4GaussHermiteQ.hh.

Constructor & Destructor Documentation

G4GaussHermiteQ::G4GaussHermiteQ	(	function	pFunction,
		G4int	nHermite
	)

Definition at line 37 of file G4GaussHermiteQ.cc.

References G4VGaussianQuadrature::fAbscissa, FatalException, G4VGaussianQuadrature::fNumber, G4VGaussianQuadrature::fWeight, G4Exception(), and python.hepunit::pi.

   : G4VGaussianQuadrature(pFunction)
{
   const G4double tolerance = 1.0e-12 ;
   const G4int maxNumber = 12 ;
   
   G4int i=1, j=1, k=1 ;
   G4double newton0=0.;
   G4double newton1=0.0, temp1=0.0, temp2=0.0, temp3=0.0, temp=0.0 ;
   G4double piInMinusQ = std::pow(pi,-0.25) ; // 1.0/std::sqrt(std::sqrt(pi)) ??

   fNumber = (nHermite +1)/2 ;
   fAbscissa = new G4double[fNumber] ;
   fWeight   = new G4double[fNumber] ;

   for(i=1;i<=fNumber;i++)
   {
      if(i == 1)
      {
         newton0 = std::sqrt((G4double)(2*nHermite + 1)) - 
                   1.85575001*std::pow((G4double)(2*nHermite + 1),-0.16666999) ;
      }
      else if(i == 2)
      {
         newton0 -= 1.14001*std::pow((G4double)nHermite,0.425999)/newton0 ;
      }
      else if(i == 3)
      {
         newton0 = 1.86002*newton0 - 0.86002*fAbscissa[0] ;
      }
      else if(i == 4)
      {
         newton0 = 1.91001*newton0 - 0.91001*fAbscissa[1] ;
      }
      else 
      {
         newton0 = 2.0*newton0 - fAbscissa[i - 3] ;
      }
      for(k=1;k<=maxNumber;k++)
      {
         temp1 = piInMinusQ ;
         temp2 = 0.0 ;
         for(j=1;j<=nHermite;j++)
         {
            temp3 = temp2 ;
            temp2 = temp1 ;
            temp1 = newton0*std::sqrt(2.0/j)*temp2
                  - std::sqrt(((G4double)(j - 1))/j)*temp3 ;
         }
         temp = std::sqrt((G4double)2*nHermite)*temp2 ;
         newton1 = newton0 ;
         newton0 = newton1 - temp1/temp ;
         if(std::fabs(newton0 - newton1) <= tolerance) 
         {
            break ;
         }
      }
      if(k > maxNumber)
      {
         G4Exception("G4GaussHermiteQ::G4GaussHermiteQ()",
                     "OutOfRange", FatalException,
                     "Too many iterations in Gauss-Hermite constructor.") ;
      }
      fAbscissa[i-1] =  newton0 ;
      fWeight[i-1] = 2.0/(temp*temp) ;
   }
}

Member Function Documentation

G4double G4GaussHermiteQ::Integral

(

)

const

Definition at line 112 of file G4GaussHermiteQ.cc.

References G4VGaussianQuadrature::fAbscissa, G4VGaussianQuadrature::fFunction, G4VGaussianQuadrature::fNumber, and G4VGaussianQuadrature::fWeight.

{
   G4double integral = 0.0 ;
   for(G4int i=0;i<fNumber;i++)
   {
      integral += fWeight[i]*(fFunction(fAbscissa[i])
                + fFunction(-fAbscissa[i])) ;
   }
   return integral ;
}

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

• G4GaussHermiteQ.hh
• G4GaussHermiteQ.cc