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G4BulirschStoer.hh
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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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// G4BulirschStoer
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//
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// Class description:
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//
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// The Bulirsch-Stoer is a controlled driver that adjusts both step size
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// and order of the method. The algorithm uses the modified midpoint and
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// a polynomial extrapolation computes the solution.
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// Author: Dmitry Sorokin, Google Summer of Code 2016
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// Supervision: John Apostolakis, CERN
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// --------------------------------------------------------------------
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#ifndef G4BULIRSCH_STOER_HH
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#define G4BULIRSCH_STOER_HH
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#include "
G4ModifiedMidpoint.hh
"
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#include "
G4FieldTrack.hh
"
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class
G4BulirschStoer
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{
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public
:
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enum class
step_result
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{
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success,
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fail
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};
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G4BulirschStoer
(
G4EquationOfMotion
* equation,
G4int
nvar,
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G4double
eps_rel,
G4double
max_dt =
DBL_MAX
);
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inline
void
set_max_dt
(
G4double
max_dt);
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inline
void
set_max_relative_error
(
G4double
eps_rel);
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// Stepper method
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//
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step_result
try_step
(
const
G4double
in
[],
const
G4double
dxdt[],
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G4double
&
t
,
G4double
out[],
G4double
& dt);
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// Reset the internal state of the stepper
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//
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void
reset
();
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inline
void
SetEquationOfMotion
(
G4EquationOfMotion
* equation);
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inline
G4EquationOfMotion
*
GetEquationOfMotion
();
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inline
G4int
GetNumberOfVariables
()
const
;
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private
:
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const
static
G4int
m_k_max
= 8;
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void
extrapolate
(
size_t
k
,
G4double
xest[]);
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G4double
calc_h_opt
(
G4double
h
,
G4double
error
,
size_t
k
)
const
;
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G4bool
set_k_opt
(
size_t
k
,
G4double
& dt);
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G4bool
in_convergence_window
(
G4int
k
)
const
;
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G4bool
should_reject
(
G4double
error
,
G4int
k
)
const
;
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// Number of vars to be integrated
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G4int
fnvar
;
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// Relative tolerance
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G4double
m_eps_rel
;
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// Modified midpoint algorithm
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G4ModifiedMidpoint
m_midpoint
;
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G4bool
m_last_step_rejected
;
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G4bool
m_first
;
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G4double
m_dt_last
;
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// G4double m_t_last;
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// Max allowed time step
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G4double
m_max_dt
;
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G4int
m_current_k_opt
;
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// G4double m_xnew[G4FieldTrack::ncompSVEC];
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G4double
m_err
[
G4FieldTrack::ncompSVEC
];
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// G4double m_dxdt[G4FieldTrack::ncompSVEC];
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// Stores the successive interval counts
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G4int
m_interval_sequence
[
m_k_max
+1];
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// Extrapolation coeffs (Neville’s algorithm)
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G4double
m_coeff
[
m_k_max
+1][
m_k_max
];
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// Costs for interval count
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G4int
m_cost
[
m_k_max
+1];
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// Sequence of states for extrapolation
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G4double
m_table
[
m_k_max
][
G4FieldTrack::ncompSVEC
];
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// Optimal step size
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G4double
h_opt
[
m_k_max
+1];
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// Work per unit step
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G4double
work
[
m_k_max
+1];
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};
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#include "G4BulirschStoer.icc"
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#endif
geant4
tree
geant4-10.6-release
source
geometry
magneticfield
include
G4BulirschStoer.hh
Built by
Jin Huang
. updated:
Wed Jun 29 2022 17:25:16
using
1.8.2 with
ECCE GitHub integration