Gabriele Cosmo
70 lines
2.7 KiB
C++
70 lines
2.7 KiB
C++
//
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// ********************************************************************
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// * DISCLAIMER *
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// * *
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// * The following disclaimer summarizes all the specific disclaimers *
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// * of contributors to this software. The specific disclaimers,which *
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// * govern, are listed with their locations in: *
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// * http://cern.ch/geant4/license *
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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. *
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// * *
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// * This code implementation is the intellectual property of the *
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// * GEANT4 collaboration. *
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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 *
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// * statement, and all its terms. *
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// ********************************************************************
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//
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//
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// $Id: G4HelixImplicitEuler.cc,v 1.5 2003/10/31 14:35:54 gcosmo Exp $
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// GEANT4 tag $Name: geant4-06-00-patch-01 $
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//
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//
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// Helix Implicit Euler:
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// x_1 = x_0 + 1/2 * ( helix(h,t_0,x_0)
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// + helix(h,t_0+h,x_0+helix(h,t0,x0) ) )
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// Second order solver.
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// Take the current derivative and add it to the current position.
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// Take the output and its derivative. Add the mean of both derivatives
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// to form the final output
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//
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// W.Wander <wwc@mit.edu> 12/09/97
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//
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// -------------------------------------------------------------------------
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#include "G4HelixImplicitEuler.hh"
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#include "G4ThreeVector.hh"
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void
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G4HelixImplicitEuler::DumbStepper( const G4double yIn[],
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G4ThreeVector Bfld,
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G4double h,
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G4double yOut[])
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{
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const G4int nvar = 6 ;
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G4double yTemp[6], yTemp2[6];
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G4ThreeVector Bfld_endpoint;
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G4int i;
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// Step forward like in the explicit euler case
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AdvanceHelix( yIn, Bfld, h, yTemp);
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// now obtain the new field value at the new point
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MagFieldEvaluate(yTemp, Bfld_endpoint);
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// and also advance along a helix for this field value
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AdvanceHelix( yIn, Bfld_endpoint, h, yTemp2);
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// we take the average
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for( i = 0; i < nvar; i++ )
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yOut[i] = 0.5 * ( yTemp[i] + yTemp2[i] );
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// NormaliseTangentVector( yOut );
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}
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