demo_fn.h

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY without ev

struct quadratic_params
  {
    double a, b, c;
  };

double quadratic (double x, void *params);
double quadratic_deriv (double x, void *params);
void quadratic_fdf (double x, void *params, 
                    double *y, double *dy);