/* Test file for mpfr_div_ui.

Copyright 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Free Software Foundation, Inc.
Contributed by the AriC and Caramel projects, INRIA.

This file is part of the GNU MPFR Library.

The GNU MPFR 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 3 of the License, or (at your
option) any later version.

The GNU MPFR 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 MPFR Library; see the file COPYING.LESSER.  If not, see
http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */

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

#include "mpfr-test.h"

static void
check (const char *ds, unsigned long u, mpfr_rnd_t rnd, const char *es)
{
  mpfr_t x, y;

  mpfr_init2 (x, 53);
  mpfr_init2 (y, 53);
  mpfr_set_str1 (x, ds);
  mpfr_div_ui (y, x, u, rnd);
  if (mpfr_cmp_str1 (y, es))
    {
      printf ("mpfr_div_ui failed for x=%s, u=%lu, rnd=%s\n", ds, u,
              mpfr_print_rnd_mode (rnd));
      printf ("expected result is %s, got", es);
      mpfr_out_str(stdout, 10, 0, y, MPFR_RNDN);
      exit (1);
    }
  mpfr_clear (x);
  mpfr_clear (y);
}

static void
special (void)
{
  mpfr_t x, y;
  unsigned xprec, yprec;

  mpfr_init (x);
  mpfr_init (y);

  mpfr_set_prec (x, 32);
  mpfr_set_prec (y, 32);
  mpfr_set_ui (x, 1, MPFR_RNDN);
  mpfr_div_ui (y, x, 3, MPFR_RNDN);

  mpfr_set_prec (x, 100);
  mpfr_set_prec (y, 100);
  mpfr_urandomb (x, RANDS);
  mpfr_div_ui (y, x, 123456, MPFR_RNDN);
  mpfr_set_ui (x, 0, MPFR_RNDN);
  mpfr_div_ui (y, x, 123456789, MPFR_RNDN);
  if (mpfr_cmp_ui (y, 0))
    {
      printf ("mpfr_div_ui gives non-zero for 0/ui\n");
      exit (1);
    }

  /* bug found by Norbert Mueller, 21 Aug 2001 */
  mpfr_set_prec (x, 110);
  mpfr_set_prec (y, 60);
  mpfr_set_str_binary (x, "0.110101110011111110011111001110011001110111000000111110001000111011000011E-44");
  mpfr_div_ui (y, x, 17, MPFR_RNDN);
  mpfr_set_str_binary (x, "0.11001010100101100011101110000001100001010110101001010011011E-48");
  if (mpfr_cmp (x, y))
    {
      printf ("Error in x/17 for x=1/16!\n");
      printf ("Expected ");
      mpfr_out_str (stdout, 2, 0, x, MPFR_RNDN);
      printf ("\nGot      ");
      mpfr_out_str (stdout, 2, 0, y, MPFR_RNDN);
      printf ("\n");
      exit (1);
    }

  /* corner case */
  mpfr_set_prec (x, 2 * mp_bits_per_limb);
  mpfr_set_prec (y, 2);
  mpfr_set_ui (x, 4, MPFR_RNDN);
  mpfr_nextabove (x);
  mpfr_div_ui (y, x, 2, MPFR_RNDN); /* exactly in the middle */
  MPFR_ASSERTN(mpfr_cmp_ui (y, 2) == 0);

  mpfr_set_prec (x, 3 * mp_bits_per_limb);
  mpfr_set_prec (y, 2);
  mpfr_set_ui (x, 2, MPFR_RNDN);
  mpfr_nextabove (x);
  mpfr_div_ui (y, x, 2, MPFR_RNDN);
  MPFR_ASSERTN(mpfr_cmp_ui (y, 1) == 0);

  mpfr_set_prec (x, 3 * mp_bits_per_limb);
  mpfr_set_prec (y, 2);
  mpfr_set_si (x, -4, MPFR_RNDN);
  mpfr_nextbelow (x);
  mpfr_div_ui (y, x, 2, MPFR_RNDD);
  MPFR_ASSERTN(mpfr_cmp_si (y, -3) == 0);

  for (xprec = 53; xprec <= 128; xprec++)
    {
      mpfr_set_prec (x, xprec);
      mpfr_set_str_binary (x, "0.1100100100001111110011111000000011011100001100110111E2");
      for (yprec = 53; yprec <= 128; yprec++)
        {
          mpfr_set_prec (y, yprec);
          mpfr_div_ui (y, x, 1, MPFR_RNDN);
          if (mpfr_cmp(x,y))
            {
              printf ("division by 1.0 fails for xprec=%u, yprec=%u\n", xprec, yprec);
              printf ("expected "); mpfr_print_binary (x); puts ("");
              printf ("got      "); mpfr_print_binary (y); puts ("");
              exit (1);
            }
        }
    }

  /* Bug reported by Mark Dickinson, 6 Nov 2007 */
  mpfr_set_si (x, 0, MPFR_RNDN);
  mpfr_set_si (y, -1, MPFR_RNDN);
  mpfr_div_ui (y, x, 4, MPFR_RNDN);
  MPFR_ASSERTN(MPFR_IS_ZERO(y) && MPFR_IS_POS(y));

  mpfr_clear (x);
  mpfr_clear (y);
}

static void
check_inexact (void)
{
  mpfr_t x, y, z;
  mpfr_prec_t px, py;
  int inexact, cmp;
  unsigned long int u;
  int rnd;

  mpfr_init (x);
  mpfr_init (y);
  mpfr_init (z);

  for (px=2; px<300; px++)
    {
      mpfr_set_prec (x, px);
      mpfr_urandomb (x, RANDS);
      do
        {
          u = randlimb ();
        }
      while (u == 0);
      for (py=2; py<300; py++)
        {
          mpfr_set_prec (y, py);
          mpfr_set_prec (z, py + mp_bits_per_limb);
          for (rnd = 0; rnd < MPFR_RND_MAX; rnd++)
            {
              inexact = mpfr_div_ui (y, x, u, (mpfr_rnd_t) rnd);
              if (mpfr_mul_ui (z, y, u, (mpfr_rnd_t) rnd))
                {
                  printf ("z <- y * u should be exact for u=%lu\n", u);
                  printf ("y="); mpfr_print_binary (y); puts ("");
                  printf ("z="); mpfr_print_binary (z); puts ("");
                  exit (1);
                }
              cmp = mpfr_cmp (z, x);
              if (((inexact == 0) && (cmp != 0)) ||
                  ((inexact > 0) && (cmp <= 0)) ||
                  ((inexact < 0) && (cmp >= 0)))
                {
                  printf ("Wrong inexact flag for u=%lu, rnd=%s\n", u,
                          mpfr_print_rnd_mode ((mpfr_rnd_t) rnd));
                  printf ("x="); mpfr_print_binary (x); puts ("");
                  printf ("y="); mpfr_print_binary (y); puts ("");
                  exit (1);
                }
            }
        }
    }

  mpfr_clear (x);
  mpfr_clear (y);
  mpfr_clear (z);
}

#define TEST_FUNCTION mpfr_div_ui
#define INTEGER_TYPE  unsigned long
#define RAND_FUNCTION(x) mpfr_random2(x, MPFR_LIMB_SIZE (x), 1, RANDS)
#include "tgeneric_ui.c"

int
main (int argc, char **argv)
{
  mpfr_t x;

  tests_start_mpfr ();

  special ();

  check_inexact ();

  check("1.0", 3, MPFR_RNDN, "3.3333333333333331483e-1");
  check("1.0", 3, MPFR_RNDZ, "3.3333333333333331483e-1");
  check("1.0", 3, MPFR_RNDU, "3.3333333333333337034e-1");
  check("1.0", 3, MPFR_RNDD, "3.3333333333333331483e-1");
  check("1.0", 2116118, MPFR_RNDN, "4.7256343927890600483e-7");
  check("1.098612288668109782", 5, MPFR_RNDN, "0.21972245773362195087");

  mpfr_init2 (x, 53);
  mpfr_set_ui (x, 3, MPFR_RNDD);
  mpfr_log (x, x, MPFR_RNDD);
  mpfr_div_ui (x, x, 5, MPFR_RNDD);
  if (mpfr_cmp_str1 (x, "0.21972245773362189536"))
    {
      printf ("Error in mpfr_div_ui for x=ln(3), u=5\n");
      exit (1);
    }
  mpfr_clear (x);

  test_generic_ui (2, 200, 100);

  tests_end_mpfr ();
  return 0;
}
