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Annotation of OpenXM_contrib/gmp/mpfr/mpfr-impl.h, Revision 1.1.1.1

1.1       maekawa     1: /* Utilities for MPFR developers, not exported.
                      2:
                      3: Copyright (C) 1999 PolKA project, Inria Lorraine and Loria
                      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 Library General Public License as published by
                      9: the Free Software Foundation; either version 2 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 Library General Public
                     15: License for more details.
                     16:
                     17: You should have received a copy of the GNU Library 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 <math.h>
                     23:
                     24: /* generate a random double using the whole range of possible values,
                     25:    including denormalized numbers, NaN, infinities, ... */
                     26: double drand()
                     27: {
                     28:   volatile double d; int *i;
                     29:
                     30:   i = (int*) &d;
                     31:   i[0] = mrand48();
                     32:   i[1] = mrand48();
                     33:   return d;
                     34: }
                     35:
                     36: /* returns the number of ulp's between a and b */
                     37: int ulp(a,b) double a,b;
                     38: {
                     39:   double eps=1.1102230246251565404e-16; /* 2^(-53) */
                     40:   if (a==0.0) {
                     41:     if (b==0.0) return 0;
                     42:     else if (b<0.0) return 2147483647;
                     43:     else return -2147483647;
                     44:   }
                     45:   b = (a-b)/a;
                     46:   if (b>0)
                     47:     return (int) floor(b/eps);
                     48:   else
                     49:     return (int) ceil(b/eps);
                     50: }
                     51:
                     52: /* return double m*2^e */
                     53: double dbl(m,e) double m; int e;
                     54: {
                     55:   if (e>=0) while (e-->0) m *= 2.0;
                     56:   else while (e++<0) m /= 2.0;
                     57:   return m;
                     58: }