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// FOSSEE IIT Bombay
#include "ODE.h"
#include "types.h"
double ODE(double initial_value, double start_time, double end_time, \
char *ode_function, double nequs, double eps_abs, double eps_rel \
double step_size)
{
double out = 0;
int status;
//Setup ODE related parameters
gsl_odeiv2_system sys = {ode_function, NULL, 2, NULL};
gsl_odeiv2_step *s = gsl_odeiv2_step_alloc (gsl_odeiv2_step_rkf45, nequs);
gsl_odeiv2_control *c = gsl_odeiv2_control_y_new (eps_abs, eps_rel);
gsl_odeiv2_evolve *e = gsl_odeiv2_evolve_alloc (nequs);
status = gsl_odeiv2_evolve_apply_fixed_step (e, c, s, &sys, &t, stepsize, x_dot);
if (status == GSL_SUCCESS) {
return out;
}
else return 0;
}
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