Gabriele Cosmo
91 lines
2.0 KiB
C++
91 lines
2.0 KiB
C++
// This code implementation is the intellectual property of
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// the RD44 GEANT4 collaboration.
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//
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// By copying, distributing or modifying the Program (or any work
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// based on the Program) you indicate your acceptance of this statement,
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// and all its terms.
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//
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// $Id: G4SimpleHeum.cc,v 2.6 1998/11/17 18:20:11 japost Exp $
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// GEANT4 tag $Name: geant4-00 $
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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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// 6.11.98. V.Grichine new data member fNumberOfVariables
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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(G4Mag_EqRhs *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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const G4double h,
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G4double yOut[])
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{
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// const G4int nvar = 6 ;
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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] +
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0.75 * dydxTemp2[i]);
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}
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// NormaliseTangentVector( yOut );
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return ;
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}
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