Gabriele Cosmo
80 lines
1.7 KiB
C++
80 lines
1.7 KiB
C++
// This code implementation is the intellectual property of
|
|
// the GEANT4 collaboration.
|
|
//
|
|
// By copying, distributing or modifying the Program (or any work
|
|
// based on the Program) you indicate your acceptance of this statement,
|
|
// and all its terms.
|
|
//
|
|
// $Id: G4SimpleRunge.cc,v 1.2 1999/12/15 14:49:50 gunter Exp $
|
|
// GEANT4 tag $Name: geant4-02-00 $
|
|
//
|
|
// Simple Runge:
|
|
//
|
|
// x_1 = x_0 + h * ( dx( t_0+h/2, x_0 + h/2 * dx( t_0, x_0) ) )
|
|
//
|
|
// second order solver
|
|
// take the derivative at a position to be assumed at the middle of the
|
|
// Step and add it to the current position.
|
|
//
|
|
//
|
|
// W.Wander <wwc@mit.edu> 12/09/97
|
|
// 6.11.98 V.Grichine new data member fNumberOfVariables
|
|
//
|
|
|
|
|
|
#include "G4SimpleRunge.hh"
|
|
#include "G4ThreeVector.hh"
|
|
|
|
////////////////////////////////////////////////////////////////
|
|
//
|
|
// Constructor
|
|
|
|
G4SimpleRunge::G4SimpleRunge(G4Mag_EqRhs *EqRhs, G4int numberOfVariables):
|
|
G4MagErrorStepper(EqRhs, numberOfVariables),
|
|
fNumberOfVariables(numberOfVariables)
|
|
{
|
|
dydxTemp = new G4double[fNumberOfVariables] ;
|
|
yTemp = new G4double[fNumberOfVariables] ;
|
|
}
|
|
|
|
|
|
/////////////////////////////////////////////////////////////////
|
|
//
|
|
// Destructor
|
|
|
|
G4SimpleRunge::~G4SimpleRunge()
|
|
{
|
|
;
|
|
}
|
|
|
|
|
|
//////////////////////////////////////////////////////////////////
|
|
//
|
|
//
|
|
|
|
void
|
|
G4SimpleRunge::DumbStepper( const G4double yIn[],
|
|
const G4double dydx[],
|
|
const G4double h,
|
|
G4double yOut[])
|
|
{
|
|
// const G4int nvar = 6 ;
|
|
G4int i;
|
|
|
|
for( i = 0; i < fNumberOfVariables; i++ )
|
|
{
|
|
yTemp[i] = yIn[i] + 0.5 * h*dydx[i] ;
|
|
}
|
|
|
|
RightHandSide(yTemp,dydxTemp);
|
|
|
|
for( i = 0; i < fNumberOfVariables; i++ )
|
|
{
|
|
yOut[i] = yIn[i] + h * ( dydxTemp[i] );
|
|
}
|
|
|
|
// NormaliseTangentVector( yOut );
|
|
|
|
return ;
|
|
}
|