/***********************************************************************
 *   FILENAME:      odes.h                                             *
 *                                                                     *
 *   PROGRAMMER:    Izzi Urieli                                        *
 *                                                                     *
 *   DATE:          12/27/94                                           *
 *                                                                     *
 *   DESCRIPTION:                                                      *
 * integrate the vector of first order ordinary differential equations *
 ***********************************************************************/

 /*  SYMBOLIC CONSTANTS: */
#define NEQU 25
 /* maximum number of first order differential equations in the set */

 /*  FUNCTION PROTOTYPES: */
void
euler(void deriv(double x, double y[], double dy[]),
      int n, double *x, double dx, double y[], double dy[]);
 /*  the simple first order Euler method  */

void
rk4(void deriv(double x, double y[], double dy[]),
    int n, double *x, double dx, double y[], double dy[]);
 /*  Classical fourth order Runge-Kutta method */

 /*  deriv  evaluates the derivative vector dy = fun(y,x)
            (supplied by the user)
     y      is the solution vector
     dy     is the derivative vector
     x, dx  is the independent variable, increment
     n      is the actual number of equations in the set.  */