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Annotation of OpenXM_contrib/gmp/mpfr/set_q.c, Revision 1.1.1.1

1.1       ohara       1: /* mpfr_set_q -- set a floating-point number from a multiple-precision rational
                      2:
                      3: Copyright 2000, 2001, 2002 Free Software Foundation, Inc.
                      4:
                      5: This file is part of the MPFR Library.
                      6:
                      7: The MPFR Library is free software; you can redistribute it and/or modify
                      8: it under the terms of the GNU Lesser General Public License as published by
                      9: the Free Software Foundation; either version 2.1 of the License, or (at your
                     10: option) any later version.
                     11:
                     12: The MPFR Library is distributed in the hope that it will be useful, but
                     13: WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
                     14: or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
                     15: License for more details.
                     16:
                     17: You should have received a copy of the GNU Lesser General Public License
                     18: along with the MPFR Library; see the file COPYING.LIB.  If not, write to
                     19: the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
                     20: MA 02111-1307, USA. */
                     21:
                     22: #include "gmp.h"
                     23: #include "gmp-impl.h"
                     24: #include "longlong.h"
                     25: #include "mpfr.h"
                     26: #include "mpfr-impl.h"
                     27:
                     28: /* set f to the rational q */
                     29: int
                     30: mpfr_set_q (mpfr_ptr f, mpq_srcptr q, mp_rnd_t rnd)
                     31: {
                     32:   mpz_srcptr num, den;
                     33:   mpfr_t n, d;
                     34:   int inexact;
                     35:   mp_prec_t prec;
                     36:
                     37:   MPFR_CLEAR_FLAGS (f);
                     38:   num = mpq_numref (q);
                     39:   if (mpz_cmp_ui (num, 0) == 0)
                     40:     {
                     41:       MPFR_SET_ZERO (f);
                     42:       MPFR_SET_POS (f);
                     43:       MPFR_RET (0);
                     44:     }
                     45:
                     46:   den = mpq_denref (q);
                     47:   mpfr_save_emin_emax ();
                     48:   prec = mpz_sizeinbase (num, 2);
                     49:   if (prec < MPFR_PREC_MIN)
                     50:     prec = MPFR_PREC_MIN;
                     51:   mpfr_init2 (n, prec);
                     52:   if (mpfr_set_z (n, num, GMP_RNDZ)) /* result is exact unless overflow */
                     53:     {
                     54:       mpfr_clear (n);
                     55:       mpfr_restore_emin_emax ();
                     56:       MPFR_SET_NAN (f);
                     57:       MPFR_RET_NAN;
                     58:     }
                     59:   prec = mpz_sizeinbase(den, 2);
                     60:   if (prec < MPFR_PREC_MIN)
                     61:     prec = MPFR_PREC_MIN;
                     62:   mpfr_init2 (d, prec);
                     63:   if (mpfr_set_z (d, den, GMP_RNDZ)) /* result is exact unless overflow */
                     64:     {
                     65:       mpfr_clear (d);
                     66:       mpfr_clear (n);
                     67:       mpfr_restore_emin_emax ();
                     68:       MPFR_SET_NAN (f);
                     69:       MPFR_RET_NAN;
                     70:     }
                     71:   inexact = mpfr_div (f, n, d, rnd);
                     72:   mpfr_clear (n);
                     73:   mpfr_clear (d);
                     74:   MPFR_RESTORE_RET (inexact, f, rnd);
                     75: }