text: #include <stdio.h>
  #include <stdlib.h>
  #include "../src/combstruct.h"
  
  int main(int argc, char **argv)
  {
    comb_sys s;
    double *y;
    double z = 0.5;
    int err = 0;
  
    s = empty_sys();
    // Y = 1/(1 - Z) + 1/(1 - 4*Z)
    add_sys(s, sum(seq(atom()), seq(prod(sum(sum(epsilon(),epsilon()),sum(epsilon(),epsilon())), atom()))));
    y = malloc(2*sys_len(s)*sizeof(double));
    z = sing_sys(s, 10e-12, 10e-5, y);
    printf("z:%.20lf y:%.20lf\n", z, y[0]);
    eval_point_sys(s, 0.5, 10e-5, y, &err);
    printf("z:0.5 y:%.20lf y':%.20lf err:%d\n", y[0], y[1], err);
    z = mean_sys(s, 500, 10e-12, 10e-5, y);
    printf("z:%.20lf y:%.20lf\n", z, y[0]);
    free(y);
    free_sys(s);
    return 0;
  }
  