text: /* Test file for mpfr_tan.
  
  Copyright 2001-2004, 2006-2019 Free Software Foundation, Inc.
  Contributed by the AriC and Caramba 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
  https://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
  51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
  
  #include "mpfr-test.h"
  
  #define TEST_FUNCTION mpfr_tan
  #define REDUCE_EMAX 262143 /* otherwise arg. reduction is too expensive */
  #include "tgeneric.c"
  
  static void
  check_nans (void)
  {
    mpfr_t  x, y;
  
    mpfr_init2 (x, 123L);
    mpfr_init2 (y, 123L);
  
    mpfr_set_nan (x);
    mpfr_tan (y, x, MPFR_RNDN);
    if (! mpfr_nan_p (y))
      {
        printf ("Error: tan(NaN) != NaN\n");
        exit (1);
      }
  
    mpfr_set_inf (x, 1);
    mpfr_tan (y, x, MPFR_RNDN);
    if (! mpfr_nan_p (y))
      {
        printf ("Error: tan(Inf) != NaN\n");
        exit (1);
      }
  
    mpfr_set_inf (x, -1);
    mpfr_tan (y, x, MPFR_RNDN);
    if (! mpfr_nan_p (y))
      {
        printf ("Error: tan(-Inf) != NaN\n");
        exit (1);
      }
  
    /* exercise recomputation */
    mpfr_set_prec (x, 14);
    mpfr_set_str_binary (x, "0.10100000101010E0");
    mpfr_set_prec (y, 24);
    mpfr_tan (y, x, MPFR_RNDU);
    mpfr_set_prec (x, 24);
    mpfr_set_str_binary (x, "101110011011001100100001E-24");
    MPFR_ASSERTN(mpfr_cmp (x, y) == 0);
  
    /* Compute ~Pi/2 to check overflow */
    mpfr_set_prec (x, 20000);
    mpfr_const_pi (x, MPFR_RNDD);
    mpfr_div_2ui (x, x, 1, MPFR_RNDN);
    mpfr_set_prec (y, 24);
    mpfr_tan (y, x, MPFR_RNDN);
    if (mpfr_cmp_str (y, "0.100011101101011000100011E20001", 2, MPFR_RNDN))
      {
        printf("Error computing tan(~Pi/2)\n");
        mpfr_dump (y);
        exit (1);
      }
  
    /* bug found by Kaveh Ghazi on 13 Jul 2007 */
    mpfr_set_prec (x, 53);
    mpfr_set_prec (y, 53);
    mpfr_set_str_binary (x, "0.10011100110111000001000010110100101000000000000000000E34");
    mpfr_tan (y, x, MPFR_RNDN);
    mpfr_set_str_binary (x, "0.1000010011001010001000010100000110100111000011010101E41");
    MPFR_ASSERTN(mpfr_cmp (x, y) == 0);
  
    mpfr_clear (x);
    mpfr_clear (y);
  }
  
  /* This test was generated from bad_cases, with GMP_CHECK_RANDOMIZE=1514257254.
     For the x value below, we have tan(x) = -1.875 + epsilon,
     thus with RNDZ it should be rounded to -1.c. */
  static void
  bug20171218 (void)
  {
    mpfr_t x, y, z;
    mpfr_init2 (x, 804);
    mpfr_init2 (y, 4);
    mpfr_init2 (z, 4);
    mpfr_set_str (x, "-1.14b1dd5f90ce0eded2a8f59c05e72daf7cc4c78f5075d73246fa420e2c026291d9377e67e7f54e925c4aed39c7b2f917424033c8612f00a19821890558d6c2cef9c60f4ad2c3b061ed53a1709dc1ec8e139627c2119c36d7ebdff0d715e559b47f740c534", 16, MPFR_RNDN);
    mpfr_tan (y, x, MPFR_RNDZ);
    mpfr_set_str (z, "-1.c", 16, MPFR_RNDN);
    MPFR_ASSERTN(mpfr_equal_p (y, z));
    mpfr_clear (x);
    mpfr_clear (y);
    mpfr_clear (z);
  }
  
  static void
  coverage (void)
  {
    mpfr_t x, y;
    int inex;
    mpfr_exp_t emax;
  
    /* exercise mpfr_round_near_x when rounding gives an overflow */
    emax = mpfr_get_emax ();
    mpfr_set_emax (-2);
    mpfr_init2 (x, 2);
    mpfr_init2 (y, 2);
    mpfr_setmax (x, mpfr_get_emax ());
    inex = mpfr_tan (y, x, MPFR_RNDA);
    MPFR_ASSERTN(inex > 0);
    MPFR_ASSERTN(mpfr_inf_p (y) && mpfr_signbit (y) == 0);
    mpfr_clear (x);
    mpfr_clear (y);
    mpfr_set_emax (emax);
  }
  
  int
  main (int argc, char *argv[])
  {
    mpfr_t x;
    unsigned int i;
    unsigned int prec[10] = {14, 15, 19, 22, 23, 24, 25, 40, 41, 52};
    unsigned int prec2[10] = {4, 5, 6, 19, 70, 95, 100, 106, 107, 108};
  
    tests_start_mpfr ();
  
    coverage ();
    bug20171218 ();
    check_nans ();
  
    mpfr_init (x);
  
    mpfr_set_prec (x, 2);
    mpfr_set_str (x, "0.5", 10, MPFR_RNDN);
    mpfr_tan (x, x, MPFR_RNDD);
    if (mpfr_cmp_ui_2exp(x, 1, -1))
      {
        printf ("mpfr_tan(0.5, MPFR_RNDD) failed\n"
                "expected 0.5, got ");
        mpfr_dump (x);
        exit (1);
      }
  
    /* check that tan(3*Pi/4) ~ -1 */
    for (i=0; i<10; i++)
      {
        mpfr_set_prec (x, prec[i]);
        mpfr_const_pi (x, MPFR_RNDN);
        mpfr_mul_ui (x, x, 3, MPFR_RNDN);
        mpfr_div_ui (x, x, 4, MPFR_RNDN);
        mpfr_tan (x, x, MPFR_RNDN);
        if (mpfr_cmp_si (x, -1))
          {
            printf ("tan(3*Pi/4) fails for prec=%u\n", prec[i]);
            exit (1);
          }
      }
  
    /* check that tan(7*Pi/4) ~ -1 */
    for (i=0; i<10; i++)
      {
        mpfr_set_prec (x, prec2[i]);
        mpfr_const_pi (x, MPFR_RNDN);
        mpfr_mul_ui (x, x, 7, MPFR_RNDN);
        mpfr_div_ui (x, x, 4, MPFR_RNDN);
        mpfr_tan (x, x, MPFR_RNDN);
        if (mpfr_cmp_si (x, -1))
          {
            printf ("tan(3*Pi/4) fails for prec=%u\n", prec2[i]);
            exit (1);
          }
      }
  
    mpfr_clear (x);
  
    test_generic (MPFR_PREC_MIN, 100, 10);
  
    data_check ("data/tan", mpfr_tan, "mpfr_tan");
    bad_cases (mpfr_tan, mpfr_atan, "mpfr_tan", 256, -256, 255, 4, 128, 800, 40);
  
    tests_end_mpfr ();
    return 0;
  }
  