/* Test mpf_sqrt_ui.

Copyright 2004 Free Software Foundation, Inc.

This file is part of the GNU MP Library.

The GNU MP Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or (at your
option) any later version.

The GNU MP Library is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
License for more details.

You should have received a copy of the GNU Lesser General Public License
along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
MA 02110-1301, USA. */

#include <stdio.h>
#include <stdlib.h>

#include "gmp.h"
#include "gmp-impl.h"
#include "tests.h"


void
check_rand (void)
{
  unsigned long      max_prec = 15;
  unsigned long      min_prec = __GMPF_BITS_TO_PREC (1);
  gmp_randstate_ptr  rands = RANDS;
  unsigned long      x, prec;
  mpf_t              r, s;
  int                i;

  mpf_init (r);
  mpf_init (s);
  refmpf_set_prec_limbs (s, 2*max_prec+10);

  for (i = 0; i < 50; i++)
    {
      /* input, a random non-zero ulong, exponentially distributed */
      do {
        x = gmp_urandomb_ui (rands,
                             gmp_urandomm_ui (rands, BITS_PER_ULONG) + 1);
      } while (x == 0);

      /* result precision */
      prec = gmp_urandomm_ui (rands, max_prec-min_prec) + min_prec;
      refmpf_set_prec_limbs (r, prec);

      mpf_sqrt_ui (r, x);
      MPF_CHECK_FORMAT (r);

      /* Expect to prec limbs of result.
         In the current implementation there's no stripping of low zero
         limbs in mpf_sqrt_ui, not even on perfect squares, so size should
         be exactly prec.  */
      if (SIZ(r) != prec)
        {
          printf ("mpf_sqrt_ui result not enough result limbs\n");
          printf    ("  x=%lu\n", x);
          printf    ("  want prec=%lu\n", prec);
          mpf_trace ("  r", r);
          printf    ("  r size %ld\n", (long) SIZ(r));
          printf    ("  r prec %ld\n", (long) PREC(r));
          abort ();
        }

      /* Must have r^2 <= x, since r has been truncated. */
      mpf_mul (s, r, r);
      if (! (mpf_cmp_ui (s, x) <= 0))
        {
          printf    ("mpf_sqrt_ui result too big\n");
          printf    ("  x=%lu\n", x);
          printf    ("  want prec=%lu\n", prec);
          mpf_trace ("  r", r);
          mpf_trace ("  s", s);
          abort ();
        }

      /* Must have (r+ulp)^2 > x.
         No overflow from refmpf_add_ulp since r is only prec limbs. */
      refmpf_add_ulp (r);
      mpf_mul (s, r, r);
      if (! (mpf_cmp_ui (s, x) > 0))
        {
          printf    ("mpf_sqrt_ui result too small\n");
          printf    ("  x=%lu\n", x);
          printf    ("  want prec=%lu\n", prec);
          mpf_trace ("  r+ulp", r);
          mpf_trace ("  s", s);
          abort ();
        }
    }

  mpf_clear (r);
  mpf_clear (s);
}

int
main (int argc, char **argv)
{
  tests_start ();
  mp_trace_base = -16;

  check_rand ();

  tests_end ();
  exit (0);
}
