Gabriele Cosmo
98 lines
3.3 KiB
C++
98 lines
3.3 KiB
C++
//
|
|
// ********************************************************************
|
|
// * License and Disclaimer *
|
|
// * *
|
|
// * The Geant4 software is copyright of the Copyright Holders of *
|
|
// * the Geant4 Collaboration. It is provided under the terms and *
|
|
// * conditions of the Geant4 Software License, included in the file *
|
|
// * LICENSE and available at http://cern.ch/geant4/license . These *
|
|
// * include a list of copyright holders. *
|
|
// * *
|
|
// * Neither the authors of this software system, nor their employing *
|
|
// * institutes,nor the agencies providing financial support for this *
|
|
// * work make any representation or warranty, express or implied, *
|
|
// * regarding this software system or assume any liability for its *
|
|
// * use. Please see the license in the file LICENSE and URL above *
|
|
// * for the full disclaimer and the limitation of liability. *
|
|
// * *
|
|
// * This code implementation is the result of the scientific and *
|
|
// * technical work of the GEANT4 collaboration. *
|
|
// * By using, copying, modifying or distributing the software (or *
|
|
// * any work based on the software) you agree to acknowledge its *
|
|
// * use in resulting scientific publications, and indicate your *
|
|
// * acceptance of all terms of the Geant4 Software license. *
|
|
// ********************************************************************
|
|
//
|
|
//
|
|
// $Id: G4SimpleRunge.cc 66356 2012-12-18 09:02:32Z gcosmo $
|
|
//
|
|
// Simple Runge:
|
|
//
|
|
// x_1 = x_0 + h * ( dx( t_0+h/2, x_0 + h/2 * dx( t_0, x_0) ) )
|
|
//
|
|
// Second order solver.
|
|
// Takes the derivative at a position to be assumed at the middle of the
|
|
// Step and adds it to the current position.
|
|
//
|
|
//
|
|
// W.Wander <wwc@mit.edu> 12/09/97
|
|
// -------------------------------------------------------------------
|
|
|
|
#include "G4SimpleRunge.hh"
|
|
#include "G4ThreeVector.hh"
|
|
|
|
////////////////////////////////////////////////////////////////
|
|
//
|
|
// Constructor
|
|
|
|
G4SimpleRunge::G4SimpleRunge(G4EquationOfMotion* EqRhs, G4int numberOfVariables)
|
|
: G4MagErrorStepper(EqRhs, numberOfVariables),
|
|
fNumberOfVariables(numberOfVariables)
|
|
{
|
|
|
|
unsigned int noVariables= std::max(numberOfVariables,
|
|
GetNumberOfStateVariables());
|
|
// To deal with Time >= 7+1
|
|
dydxTemp = new G4double[noVariables] ;
|
|
yTemp = new G4double[noVariables] ;
|
|
}
|
|
|
|
|
|
/////////////////////////////////////////////////////////////////
|
|
//
|
|
// Destructor
|
|
|
|
G4SimpleRunge::~G4SimpleRunge()
|
|
{
|
|
delete[] dydxTemp;
|
|
delete[] yTemp;
|
|
}
|
|
|
|
//////////////////////////////////////////////////////////////////
|
|
//
|
|
//
|
|
|
|
void
|
|
G4SimpleRunge::DumbStepper( const G4double yIn[],
|
|
const G4double dydx[],
|
|
G4double h,
|
|
G4double yOut[])
|
|
{
|
|
// Initialise time to t0, needed when it is not updated by the integration.
|
|
yTemp[7] = yOut[7] = yIn[7]; // Better to set it to NaN; // TODO
|
|
|
|
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] );
|
|
}
|
|
}
|