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/* test file for mpc_cos.
Copyright (C) 2007 INRIA.
This file is part of the MPC Library.
The MPC 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 MPC 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 MPC Library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA. */
#include <stdio.h>
#include <stdlib.h>
#include "gmp.h"
#include "mpfr.h"
#include "mpc.h"
int
main()
{
mpc_t x, z, t, u;
mpfr_t f, g;
mp_prec_t prec;
mpc_init (x);
mpc_init (z);
mpc_init (t);
mpc_init (u);
mpfr_init (g);
for (prec = 2; prec <= 1000; prec++)
{
mpc_set_prec (x, prec);
mpc_set_prec (z, prec);
mpc_set_prec (t, prec);
mpc_set_prec (u, 4*prec);
mpfr_set_prec (g, prec);
/* check that cos(I*b) = cosh(b) */
mpfr_set_ui (MPC_RE (x), 0, GMP_RNDN);
mpfr_random (MPC_IM (x));
mpc_cos (z, x, MPC_RNDNN);
mpfr_cosh (g, MPC_IM(x), GMP_RNDN);
if (mpfr_cmp_ui (MPC_IM(z), 0) || mpfr_cmp (g, MPC_RE(z)))
{
fprintf (stderr, "Error in mpc_cos: cos(I*x) <> cosh(x)\n"
"got ");
mpc_out_str (stderr, 10, 0, z, MPC_RNDNN);
fprintf (stderr, "\nexpected ");
mpfr_set (MPC_RE (z), g, GMP_RNDN);
mpfr_set_ui (MPC_IM (z), 0, GMP_RNDN);
mpc_out_str (stderr, 10, 0, z, MPC_RNDNN);
fprintf (stderr, "\n");
exit (1);
}
}
/* We also compute the result with four times the precision and check */
/* whether the rounding is correct. Error reports in this part of the */
/* algorithm might still be wrong, though, since there are two */
/* consecutive roundings. */
mpc_random (x);
mpc_cos (z, x, MPC_RNDNN);
mpc_cos (u, x, MPC_RNDNN);
mpc_set (t, u, MPC_RNDNN);
if (mpc_cmp (z, t))
{
fprintf (stderr, "rounding in cos might be incorrect for\nx=");
mpc_out_str (stderr, 2, 0, x, MPC_RNDNN);
fprintf (stderr, "\nmpc_cos gives ");
mpc_out_str (stderr, 2, 0, z, MPC_RNDNN);
fprintf (stderr, "\nmpc_cos quadruple precision gives ");
mpc_out_str (stderr, 2, 0, u, MPC_RNDNN);
fprintf (stderr, "\nand is rounded to ");
mpc_out_str (stderr, 2, 0, t, MPC_RNDNN);
fprintf (stderr, "\n");
exit (1);
}
mpc_clear (x);
mpc_clear (z);
mpc_clear (t);
mpc_clear (u);
mpfr_clear (g);
return 0;
}
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