1  /* Declarations of random_deviate routines for mpfr_erandom and mpfr_nrandom.
       2  
       3  Copyright 2013-2023 Free Software Foundation, Inc.
       4  Contributed by Charles Karney <charles@karney.com>, SRI International.
       5  
       6  This file is part of the GNU MPFR Library.
       7  
       8  The GNU MPFR Library is free software; you can redistribute it and/or modify
       9  it under the terms of the GNU Lesser General Public License as published by
      10  the Free Software Foundation; either version 3 of the License, or (at your
      11  option) any later version.
      12  
      13  The GNU MPFR Library is distributed in the hope that it will be useful, but
      14  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
      15  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
      16  License for more details.
      17  
      18  You should have received a copy of the GNU Lesser General Public License
      19  along with the GNU MPFR Library; see the file COPYING.LESSER.  If not, see
      20  https://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
      21  51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
      22  
      23  #if !defined(MPFR_RANDOM_DEVIATE_H)
      24  #define MPFR_RANDOM_DEVIATE_H 1
      25  
      26  #include "mpfr-impl.h"
      27  
      28  /* This should be an unsigned type with a width of at least 32 and capable of
      29   * representing at least 2*MPFR_PREC_MAX.  This is used to count the bits in
      30   * the fraction of a mpfr_random_deviate_t.  See the checks made on this type
      31   * in random_deviate_generate. */
      32  typedef unsigned long mpfr_random_size_t;
      33  
      34  typedef struct {
      35    mpfr_random_size_t e;       /* total number of bits in the fraction */
      36    unsigned long h;            /* the high W bits of the fraction */
      37    mpz_t f;                    /* the rest of the fraction */
      38  } __mpfr_random_deviate_struct;
      39  
      40  typedef __mpfr_random_deviate_struct mpfr_random_deviate_t[1];
      41  typedef __mpfr_random_deviate_struct *mpfr_random_deviate_ptr;
      42  
      43  #if defined(__cplusplus)
      44  extern "C" {
      45  #endif
      46  
      47  /* allocate and set to (0,1) */
      48  __MPFR_DECLSPEC void
      49    mpfr_random_deviate_init (mpfr_random_deviate_ptr);
      50  
      51  /* reset to (0,1) */
      52  __MPFR_DECLSPEC void
      53    mpfr_random_deviate_reset (mpfr_random_deviate_ptr);
      54  
      55  /* deallocate */
      56  __MPFR_DECLSPEC void
      57    mpfr_random_deviate_clear (mpfr_random_deviate_ptr);
      58  
      59  /* swap two random deviates */
      60  __MPFR_DECLSPEC void
      61    mpfr_random_deviate_swap (mpfr_random_deviate_ptr,
      62                              mpfr_random_deviate_ptr);
      63  
      64  /* return kth bit of fraction, representing 2^-k */
      65  __MPFR_DECLSPEC int
      66    mpfr_random_deviate_tstbit (mpfr_random_deviate_ptr,
      67                                mpfr_random_size_t,
      68                                gmp_randstate_t);
      69  
      70  /* compare two random deviates, x < y */
      71  __MPFR_DECLSPEC int
      72    mpfr_random_deviate_less (mpfr_random_deviate_ptr,
      73                              mpfr_random_deviate_ptr,
      74                              gmp_randstate_t);
      75  
      76  /* set mpfr_t z = (neg ? -1 : 1) * (n + x) */
      77  __MPFR_DECLSPEC int
      78    mpfr_random_deviate_value (int, unsigned long,
      79                               mpfr_random_deviate_ptr, mpfr_ptr,
      80                               gmp_randstate_t, mpfr_rnd_t);
      81  
      82  #if defined(__cplusplus)
      83  }
      84  #endif
      85  
      86  #endif