rk4.c File Reference

#include "mbs_rk4.h"
#include "integrator.h"

Functions
int	rk4 (double y[], double dydx[], int n, double x, double h, double yout[], int(*derivs)(double, double[], double[], MbsData *, MbsDirdyn *), MbsData *s, MbsDirdyn *dd)
	Runge Kutta 4 integrator implementation Given values for the variables y[1..n] and their derivatives dydx[1..n] known at x, use the fourth-order Runge-Kutta method to advance the solution over an interval h and return the incremented variables as yout[1..n], which need not be a distinct array from y. More...

Function Documentation

rk4()

int rk4	(	double	y[],
		double	dydx[],
		int	n,
		double	x,
		double	h,
		double	yout[],
		int(*)(double, double[], double[], MbsData *, MbsDirdyn *)	derivs,
		MbsData *	s,
		MbsDirdyn *	dd
	)

Runge Kutta 4 integrator implementation Given values for the variables y[1..n] and their derivatives dydx[1..n] known at x, use the fourth-order Runge-Kutta method to advance the solution over an interval h and return the incremented variables as yout[1..n], which need not be a distinct array from y.

The user supplies the routine derivs(x,y,dydx), which returns derivatives dydx at x.

Parameters

y	state vector of variable
dydx	derivative of y by x
n	number of variables
x	current time value, at which the function needs to be computed
h	time step
yout	solution of the incremented variables
derivs	The function computing f'
s	the MbsData structure of the model on which dirdyn analysis is computed.
dd	the MbsDirdyn structure related to the integration.

Returns

Error status, <0 in case of failure.