1 files changed, 67 insertions, 0 deletions
diff --git a/src/c/differential_calculus/ode/dodea.c b/src/c/differential_calculus/ode/dodea.c
new file mode 100644
index 00000000..97d56a1a
--- /dev/null
+++ b/src/c/differential_calculus/ode/dodea.c
@@ -0,0 +1,67 @@
+/* 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);
+}