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b58ddff026
* merged mpfr 3.0.0 and gmp 5.0.1 in buildtools trunk git-svn-id: file:///srv/svn/repos/haiku/buildtools/trunk@37378 a95241bf-73f2-0310-859d-f6bbb57e9c96
99 lines
3.1 KiB
C
99 lines
3.1 KiB
C
/* mpfr_urandomb (rop, state, nbits) -- Generate a uniform pseudorandom
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real number between 0 (inclusive) and 1 (exclusive) of size NBITS,
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using STATE as the random state previously initialized by a call to
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gmp_randinit_lc_2exp_size().
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Copyright 2000, 2001, 2002, 2003, 2004, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
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Contributed by the Arenaire and Cacao projects, INRIA.
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This file is part of the GNU MPFR Library.
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The GNU MPFR Library is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 3 of the License, or (at your
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option) any later version.
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The GNU MPFR Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the GNU MPFR Library; see the file COPYING.LESSER. If not, see
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http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
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51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
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#define MPFR_NEED_LONGLONG_H
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#include "mpfr-impl.h"
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void
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mpfr_rand_raw (mp_ptr mp, gmp_randstate_t rstate, unsigned long int nbits)
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{
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mpz_t z;
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/* To be sure to avoid the potential allocation of mpz_urandomb */
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ALLOC(z) = SIZ(z) = (nbits / GMP_NUMB_BITS) + 1;
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PTR(z) = mp;
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mpz_urandomb(z, rstate, nbits);
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}
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int
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mpfr_urandomb (mpfr_ptr rop, gmp_randstate_t rstate)
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{
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mp_ptr rp;
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mpfr_prec_t nbits;
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mp_size_t nlimbs;
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mp_size_t k; /* number of high zero limbs */
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mpfr_exp_t exp;
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int cnt;
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rp = MPFR_MANT (rop);
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nbits = MPFR_PREC (rop);
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nlimbs = MPFR_LIMB_SIZE (rop);
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MPFR_SET_POS (rop);
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/* Uniform non-normalized significand */
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mpfr_rand_raw (rp, rstate, nlimbs * GMP_NUMB_BITS);
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/* If nbits isn't a multiple of GMP_NUMB_BITS, mask the low bits */
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cnt = nlimbs * GMP_NUMB_BITS - nbits;
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if (MPFR_LIKELY (cnt != 0))
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rp[0] &= ~MPFR_LIMB_MASK (cnt);
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/* Count the null significant limbs and remaining limbs */
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exp = 0;
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k = 0;
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while (nlimbs != 0 && rp[nlimbs - 1] == 0)
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{
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k ++;
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nlimbs --;
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exp -= GMP_NUMB_BITS;
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}
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if (MPFR_LIKELY (nlimbs != 0)) /* otherwise value is zero */
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{
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count_leading_zeros (cnt, rp[nlimbs - 1]);
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/* Normalization */
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if (mpfr_set_exp (rop, exp - cnt))
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{
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/* If the exponent is not in the current exponent range, we
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choose to return a NaN as this is probably a user error.
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Indeed this can happen only if the exponent range has been
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reduced to a very small interval and/or the precision is
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huge (very unlikely). */
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MPFR_SET_NAN (rop);
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__gmpfr_flags |= MPFR_FLAGS_NAN; /* Can't use MPFR_RET_NAN */
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return 1;
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}
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if (cnt != 0)
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mpn_lshift (rp + k, rp, nlimbs, cnt);
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if (k != 0)
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MPN_ZERO (rp, k);
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}
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else
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MPFR_SET_ZERO (rop);
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return 0;
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}
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