/* Inverse of the error function {erf()} */
/* Last edited on 2023-12-15 04:09:49 by stolfi */
#ifndef erfinv_H
#define erfinv_H

#define _GNU_SOURCE
#include <math.h>

#include <affirm.h>
#include <erfinv.h>

double erfinv(double y);
  /* Functional inverse of the error function {erf},
    namely such that {erf(erfinv(y)) = y} for {y} in {[-1_1]}, apart from roundoff errors
    which may be significant near the ends of that range. Also
    {erfinv(erf(x)) = x} for any {x}, apart from roundoff errors
    which may be significant for {x} far from 0. */

#endif