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Annotation of OpenXM_contrib/gmp/mpfr/set_q.c, Revision 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: }