Gabriele Cosmo
95 lines
3.3 KiB
C++
95 lines
3.3 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: G4CashKarpRKF45.hh,v 1.7 2001/07/11 09:59:06 gunter Exp $
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// GEANT4 tag $Name: geant4-05-00 $
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//
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//
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// class G4CashKarpRKF45
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//
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// Class description:
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//
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// The Cash-Karp Runge-Kutta-Fehlberg 4/5 method is an embedded fourth
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// order method (giving fifth-order accuracy) for the solution of an ODE.
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// Two different fourth order estimates are calculated; their difference
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// gives an error estimate. [ref. Numerical Recipes in C, 2nd Edition]
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// It is used to integrate the equations of the motion of a particle
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// in a magnetic field.
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// History:
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// - Created. J.Apostolakis, V.Grichine - 30.1.97
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#ifndef G4CashKARP_RKF45
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#define G4CashKARP_RKF45
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#include "G4MagIntegratorStepper.hh"
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class G4CashKarpRKF45 : public G4MagIntegratorStepper
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{
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public: // with description
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G4CashKarpRKF45(G4EquationOfMotion *EqRhs, G4int numberOfVariables = 6, G4bool primary= true) ;
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~G4CashKarpRKF45() ;
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void Stepper( const G4double y[],
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const G4double dydx[],
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G4double h,
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G4double yout[],
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G4double yerr[] ) ;
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void StepWithEst( const G4double yIn[],
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const G4double dydx[],
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G4double Step,
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G4double yOut[],
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G4double& alpha2,
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G4double& beta2,
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const G4double B1[],
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G4double B2[] ) ;
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public: // without description
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G4double DistChord() const;
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G4int IntegratorOrder() const { return 4; }
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private:
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G4CashKarpRKF45(const G4CashKarpRKF45&);
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G4CashKarpRKF45& operator=(const G4CashKarpRKF45&);
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// Private copy constructor and assignment operator.
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private:
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G4int fNumberOfVariables ;
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G4double *ak2, *ak3, *ak4, *ak5, *ak6, *ak7, *yTemp, *yIn; // scratch space
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// for DistChord calculations
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G4double fLastStepLength;
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G4double *fLastInitialVector, *fLastFinalVector, *fLastDyDx, *fMidVector, *fMidError;
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G4CashKarpRKF45* fAuxStepper;
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};
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#endif /* G4CashKARP_RKF45 */
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