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Annotation of OpenXM_contrib/gmp/mpfr/reldiff.c, Revision 1.1

1.1     ! ohara       1: /* mpfr_reldiff -- compute relative difference of two floating-point numbers.
        !             2:
        !             3: Copyright 2000, 2001 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 <stdio.h>
        !            23: #include "gmp.h"
        !            24: #include "gmp-impl.h"
        !            25: #include "mpfr.h"
        !            26: #include "mpfr-impl.h"
        !            27:
        !            28: /* reldiff(b, c) = abs(b-c)/b */
        !            29: void
        !            30: mpfr_reldiff (mpfr_ptr a, mpfr_srcptr b, mpfr_srcptr c, mp_rnd_t rnd_mode)
        !            31: {
        !            32:   mpfr_t b_copy;
        !            33:
        !            34:   if (MPFR_IS_NAN(b) || MPFR_IS_NAN(c))
        !            35:     { MPFR_CLEAR_FLAGS(a); MPFR_SET_NAN(a); return; }
        !            36:   if (MPFR_IS_INF(b))
        !            37:     {
        !            38:       if (MPFR_IS_INF(c) && (MPFR_SIGN(c) == MPFR_SIGN(b)))
        !            39:        { MPFR_CLEAR_FLAGS(a); MPFR_SET_ZERO(a); return; }
        !            40:       else
        !            41:        { MPFR_CLEAR_FLAGS(a); MPFR_SET_NAN(a); return; }
        !            42:     }
        !            43:
        !            44:   if (MPFR_IS_INF(c))
        !            45:     {
        !            46:       MPFR_SET_SAME_SIGN(a, b);
        !            47:       MPFR_CLEAR_FLAGS(a);
        !            48:       MPFR_SET_INF(a);
        !            49:       return;
        !            50:     }
        !            51:
        !            52:   if (MPFR_IS_ZERO(b)) /* reldiff = abs(c)/c = sign(c) */
        !            53:     mpfr_set_ui(a, MPFR_SIGN(c), rnd_mode);
        !            54:   else
        !            55:     {
        !            56:       if (a == b)
        !            57:         {
        !            58:           mpfr_init2 (b_copy, MPFR_PREC(b));
        !            59:           mpfr_set (b_copy, b, GMP_RNDN);
        !            60:         }
        !            61:
        !            62:       mpfr_sub (a, b, c, rnd_mode);
        !            63:       mpfr_abs (a, a, rnd_mode); /* for compatibility with MPF */
        !            64:       mpfr_div (a, a, (a == b) ? b_copy : b, rnd_mode);
        !            65:
        !            66:       if (a == b)
        !            67:         mpfr_clear (b_copy);
        !            68:     }
        !            69: }
        !            70: