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Diffstat (limited to 'texp.c')
| -rw-r--r-- | texp.c | 104 |
1 files changed, 104 insertions, 0 deletions
@@ -0,0 +1,104 @@ +/* test file for mpc_exp. + +Copyright (C) 2002 Andreas Enge, Paul Zimmermann + +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 (f); + 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 (f, prec); + mpfr_set_prec (g, prec); + + /* check that exp(I*b) = cos(b) + I*sin(b) */ + mpfr_set_ui (MPC_RE (x), 0, GMP_RNDN); + mpfr_random (MPC_IM (x)); + + mpc_exp (z, x, MPC_RNDNN); + mpfr_sin_cos (f, g, MPC_IM(x), GMP_RNDN); + if (mpfr_cmp (g, MPC_RE(z)) || mpfr_cmp (f, MPC_IM(z))) + { + fprintf (stderr, "Error in mpc_exp: exp(I*x) <> cos(x)+I*sin(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 (MPC_IM(z), f, 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_exp (z, x, MPC_RNDNN); + mpc_exp (t, x, MPC_RNDNN); + mpc_set (u, t, MPC_RNDNN); + + if (mpc_cmp (z, t)) + { + fprintf (stderr, "rounding in exp might be incorrect for\nx="); + mpc_out_str (stderr, 2, 0, x, MPC_RNDNN); + fprintf (stderr, "\nmpc_exp gives "); + mpc_out_str (stderr, 2, 0, z, MPC_RNDNN); + fprintf (stderr, "\nmpc_exp 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 (f); + mpfr_clear (g); + + return 0; +} |