Gabriele Cosmo
101 lines
3.4 KiB
C++
101 lines
3.4 KiB
C++
//
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// ********************************************************************
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// * License and Disclaimer *
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// * *
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// * The Geant4 software is copyright of the Copyright Holders of *
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// * the Geant4 Collaboration. It is provided under the terms and *
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// * conditions of the Geant4 Software License, included in the file *
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// * LICENSE and available at http://cern.ch/geant4/license . These *
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// * include a list of copyright holders. *
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// * *
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// * Neither the authors of this software system, nor their employing *
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// * institutes,nor the agencies providing financial support for this *
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// * work make any representation or warranty, express or implied, *
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// * regarding this software system or assume any liability for its *
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// * use. Please see the license in the file LICENSE and URL above *
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// * for the full disclaimer and the limitation of liability. *
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// * *
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// * This code implementation is the result of the scientific and *
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// * technical work of the GEANT4 collaboration. *
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// * By using, copying, modifying or distributing the software (or *
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// * any work based on the software) you agree to acknowledge its *
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// * use in resulting scientific publications, and indicate your *
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// * acceptance of all terms of the Geant4 Software license. *
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// ********************************************************************
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//
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//
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//
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// Simple Heum:
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// x_1 = x_0 + h *
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// 1/4 * dx(t0,x0) +
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// 3/4 * dx(t0+2/3*h, x0+2/3*h*(dx(t0+h/3,x0+h/3*dx(t0,x0))))
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//
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// Third order solver.
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//
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// W.Wander <wwc@mit.edu> 12/09/97
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// -------------------------------------------------------------------
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#include "G4SimpleHeum.hh"
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#include "G4ThreeVector.hh"
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///////////////////////////////////////////////////////////////////////////
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//
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// Constructor
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G4SimpleHeum::G4SimpleHeum(G4EquationOfMotion *EqRhs, G4int num_variables):
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G4MagErrorStepper(EqRhs, num_variables),
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fNumberOfVariables(num_variables)
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{
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dydxTemp = new G4double[fNumberOfVariables] ;
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dydxTemp2 = new G4double[fNumberOfVariables] ;
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yTemp = new G4double[fNumberOfVariables] ;
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yTemp2 = new G4double[fNumberOfVariables] ;
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}
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//////////////////////////////////////////////////////////////////////////
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//
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// Destructor
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G4SimpleHeum::~G4SimpleHeum()
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{
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delete[] dydxTemp;
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delete[] dydxTemp2;
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delete[] yTemp;
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delete[] yTemp2;
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}
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//////////////////////////////////////////////////////////////////////
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//
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//
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void
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G4SimpleHeum::DumbStepper( const G4double yIn[],
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const G4double dydx[],
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G4double h,
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G4double yOut[])
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{
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G4int i;
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for( i = 0; i < fNumberOfVariables; i++ )
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{
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yTemp[i] = yIn[i] + (1.0/3.0) * h * dydx[i] ;
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}
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RightHandSide(yTemp,dydxTemp);
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for( i = 0; i < fNumberOfVariables; i++ )
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{
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yTemp2[i] = yIn[i] + (2.0/3.0) * h * dydxTemp[i] ;
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}
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RightHandSide(yTemp2,dydxTemp2);
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for( i = 0; i < fNumberOfVariables; i++ )
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{
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yOut[i] = yIn[i] + h * (0.25 * dydx[i] + 0.75 * dydxTemp2[i]);
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}
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if ( fNumberOfVariables == 12 ) { NormalisePolarizationVector( yOut ); }
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}
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