[dd20b8]: include / propagator / OdePropagator.hpp  Maximize  Restore  History

Download this file

109 lines (95 with data), 4.1 kB

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
/*
* Copyright (C) 2013-2014 Ulf Lorenz
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Library General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#ifndef PROPAGATOR_ODEPROPAGATOR_HPP
#define PROPAGATOR_ODEPROPAGATOR_HPP
#include <memory>
#include <extern/odeint_impl.hpp>
#include <propagator/ode_private.hpp>
#include <propagator/Propagator.hpp>
#include <operator/LinearOperator.hpp>
namespace wavepacket {
/** Template class for the various standard ODE solvers.
*
* The differential equation to solve is the Schroedinger equation
*
* \f[
* \dot \psi(t) = -i \hat H(t) \psi(t)
* \f]
*
* or an analogous Liouville equation (note that most of the high-level operators
* (SchroedingerOperator etc.) implicitly add the (-i)-term).
*
* If the wave function is represented by the value at its grid points (or
* equivalently by the expansion coefficients when expanding in a basis), then
* this equation turns into a set of ordinary differential equations (ODEs) coupled
* by the matrix H. These can then be solved using common ODE solvers.
*
* Do *not* use this template class directly, it only combines the code for
* all ODE-based propagators, but has the actual type of the algorithm as a
* template parameter. Instead, use one of the typedefs:
*
* - OdePropagator_RK54 for the 4-th order CashKarp algorithm
* - OdePropagator_RK5 for the 5-th order Dopri algorithm
* - OdePropagator_RK78 for the seventh-order Fehlberg algorithm
* - OdePropagator_BS for the Bulirsch-Stoer algorithm.
*
* All propagators implement error control, so you do not have to worry about
* step sizes.
*
* Implementation detail: The template parameter for this function is a factory
* structure, which also knows the type to return, see ControlledFactory and
* SimpleFactory below.
*
* \ingroup propagator
*/
template<class Factory>
class OdePropagator : public Propagator {
public:
/** Creates a new propagator.
*
* @param hamilt the Hamiltonian/Liouvillian to use.
* @param relError the relative error to tolerate per elementary step
* @param absError the absolute error to tolerate per elementary step
*
* @throws std::invalid_argument if the Hamiltonian is an invalid pointer or
* an error is negative.
*/
explicit OdePropagator(const std::shared_ptr<LinearOperator>& hamilt,
double relError=1e-6, double absError=1e-10);
CTensor propagate(const CTensor& state, double t0, double t1) override;
private:
Factory factory;
std::shared_ptr<LinearOperator> hamiltonian;
typename Factory::controlled_type solver;
};
// definition of the individual propagators
// note: ode_private.hpp contains the internal definitions.
typedef OdePropagator<ode_private::SimpleFactory<ode_private::bs_type>>
OdePropagator_BS;
typedef OdePropagator<ode_private::ControlledFactory<ode_private::rk54_type>>
OdePropagator_RK54;
typedef OdePropagator<ode_private::ControlledFactory<ode_private::rk5_type>>
OdePropagator_RK5;
typedef OdePropagator<ode_private::ControlledFactory<ode_private::rk78_type>>
OdePropagator_RK78;
// define a single template instantiation
extern template class OdePropagator<ode_private::SimpleFactory<ode_private::bs_type>>;
extern template class OdePropagator<ode_private::ControlledFactory<ode_private::rk54_type>>;
extern template class OdePropagator<ode_private::ControlledFactory<ode_private::rk5_type>>;
extern template class OdePropagator<ode_private::ControlledFactory<ode_private::rk78_type>>;
} // namespace wavepacket
#endif /* PROPAGATOR_ODEPROPAGATOR_HPP */

Get latest updates about Open Source Projects, Conferences and News.

Sign up for the SourceForge newsletter:





No, thanks