#include  "demo_fn.h"

double
xenx (double x, void *params)
{
//  struct xenx_params *p 
//    = (struct xenx_params *) params;

//  double a = p->a;
//  double b = p->b;

  return x / exp(x);
}

double
xenx_deriv (double x, void *params)
{
  return (1-x) / exp(x);
}

void
xenx_fdf (double x, void *params, 
               double *y, double *dy)
{
  *y = x / exp(x);
  *dy = (1-x) / exp(x);
}