runge.h
/*
* Runge-Kutta integrator originally written for PKDGRAV by Thomas
* Quinn
*/
void
RungeKutta(void *CTX,
void (*deriv)(void *, double, double *, double*),
int nDep, /* number of dependent variables */
double tin, /* independent variable */
double *xin, /* array of input */
double tout,
double *xout, /* array of output */
int nSteps);