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/* Copyright (C) 2016 - IIT Bombay - FOSSEE
This file must be used under the terms of the CeCILL.
This source file is licensed as described in the file COPYING, which
you should have received as part of this distribution. The terms
are also available at
http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt
Author: Siddhesh Wani
Organization: FOSSEE, IIT Bombay
Email: toolbox@scilab.in
*/
/*Function for solving ODEs using GSL library*/
#include "ode.h"
#include "types.h"
#include <gsl/gsl_errno.h>
#include <gsl/gsl_matrix.h>
#include <gsl/gsl_odeiv2.h>
void dodea(double *initial_value, double start_time, double end_time, \
int (*ode_function)(double, double*, double*, int*), char *solver_type, double nequs, double eps_abs, \
double eps_rel, double step_size, int *params, double *out)
{
double t = start_time;
gsl_odeiv2_step_type *step_type;
/*Initialise output to initial state*/
int counter = 0;
for (counter = 0; counter<nequs;counter++)
{
out[counter] = initial_value[counter];
}
/*Setup ODE related parameters*/
gsl_odeiv2_system sys = {ode_function, NULL, nequs, params};
/*Select step solver*/
if (solver_type == "adams")
step_type = gsl_odeiv2_step_msadams;
if (solver_type == "stiff")
step_type = gsl_odeiv2_step_msbdf;
if (solver_type == "rk")
step_type = gsl_odeiv2_step_rk4;
if (solver_type == "rkf")
step_type = gsl_odeiv2_step_rkf45;
if (solver_type == "root")
step_type = gsl_odeiv2_step_rkck;
if (solver_type == "discrete")
step_type = gsl_odeiv2_step_rk8pd;
else
step_type = gsl_odeiv2_step_rkf45;
gsl_odeiv2_step *s = gsl_odeiv2_step_alloc (step_type, nequs);
gsl_odeiv2_control *c = gsl_odeiv2_control_y_new (eps_abs, eps_rel);
gsl_odeiv2_evolve *e = gsl_odeiv2_evolve_alloc (nequs);
while(t < end_time)
{
gsl_odeiv2_evolve_apply_fixed_step (e, c, s, &sys, &t, step_size, out);
}
gsl_odeiv2_evolve_free (e);
gsl_odeiv2_control_free (c);
gsl_odeiv2_step_free (s);
}
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