libguile/random.h

   1 /* classes: h_files */
   2
   3 #ifndef RANDOMH
   4 #define RANDOMH
   5 /*      Copyright (C) 1999 Free Software Foundation, Inc.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2, or (at your option)
  10  * any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this software; see the file COPYING.  If not, write to
  19  * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  20  * Boston, MA 02111-1307 USA
  21  *
  22  * As a special exception, the Free Software Foundation gives permission
  23  * for additional uses of the text contained in its release of GUILE.
  24  *
  25  * The exception is that, if you link the GUILE library with other files
  26  * to produce an executable, this does not by itself cause the
  27  * resulting executable to be covered by the GNU General Public License.
  28  * Your use of that executable is in no way restricted on account of
  29  * linking the GUILE library code into it.
  30  *
  31  * This exception does not however invalidate any other reasons why
  32  * the executable file might be covered by the GNU General Public License.
  33  *
  34  * This exception applies only to the code released by the
  35  * Free Software Foundation under the name GUILE.  If you copy
  36  * code from other Free Software Foundation releases into a copy of
  37  * GUILE, as the General Public License permits, the exception does
  38  * not apply to the code that you add in this way.  To avoid misleading
  39  * anyone as to the status of such modified files, you must delete
  40  * this exception notice from them.
  41  *
  42  * If you write modifications of your own for GUILE, it is your choice
  43  * whether to permit this exception to apply to your modifications.
  44  * If you do not wish that, delete this exception notice.  */
  45
  46 /* Software engineering face-lift by Greg J. Badros, 11-Dec-1999,
  47    gjb@cs.washington.edu, http://www.cs.washington.edu/homes/gjb */
  48 \f
  49
  50 #include "libguile/__scm.h"
  51
  52 \f
  53 /*
  54  * A plugin interface for RNGs
  55  *
  56  * Using this interface, it is possible for the application to tell
  57  * libguile to use a different RNG.  This is desirable if it is
  58  * necessary to use the same RNG everywhere in the application in
  59  * order to prevent interference, if the application uses RNG
  60  * hardware, or if the application has special demands on the RNG.
  61  *
  62  * Look how the default generator is "plugged in" in scm_init_random().
  63  */
  64
  65 typedef struct scm_rstate {
  66   int reserved0;
  67   double reserved1;
  68   /* Custom fields follow here */
  69 } scm_rstate;
  70
  71 typedef struct scm_rng {
  72   size_t rstate_size;                               /* size of random state */
  73   unsigned long (*random_bits) (scm_rstate *state); /* gives 32 random bits */
  74   void (*init_rstate) (scm_rstate *state, char *seed, int n);
  75   scm_rstate *(*copy_rstate) (scm_rstate *state);
  76 } scm_rng;
  77
  78 extern scm_rng scm_the_rng;
  79
  80 \f
  81 /*
  82  * Default RNG
  83  */
  84 typedef struct scm_i_rstate {
  85   scm_rstate rstate;
  86   unsigned long w;
  87   unsigned long c;
  88 } scm_i_rstate;
  89
  90 extern unsigned long scm_i_uniform32 (scm_i_rstate *);
  91 extern void scm_i_init_rstate (scm_i_rstate *, char *seed, int n);
  92 extern scm_i_rstate *scm_i_copy_rstate (scm_i_rstate *);
  93
  94 \f
  95 /*
  96  * Random number library functions
  97  */
  98 extern scm_rstate *scm_c_make_rstate (char *, int);
  99 extern scm_rstate *scm_c_default_rstate (void);
 100 #define scm_c_uniform32(RSTATE) scm_the_rng.random_bits (RSTATE)
 101 extern double scm_c_uniform01 (scm_rstate *);
 102 extern double scm_c_normal01 (scm_rstate *);
 103 extern double scm_c_exp1 (scm_rstate *);
 104 extern unsigned long scm_c_random (scm_rstate *, unsigned long m);
 105 extern SCM scm_c_random_bignum (scm_rstate *, SCM m);
 106
 107 \f
 108 /*
 109  * Scheme level interface
 110  */
 111 extern long scm_tc16_rstate;
 112 #define SCM_RSTATE(obj) ((scm_rstate *) SCM_CDR (obj))
 113 #define SCM_RSTATEP(obj) (SCM_NIMP(obj) && (SCM_TYP16 (obj) == scm_tc16_rstate))
 114
 115 extern unsigned char scm_masktab[256];
 116
 117 extern SCM scm_var_random_state;
 118 extern SCM scm_random (SCM n, SCM state);
 119 extern SCM scm_copy_random_state (SCM state);
 120 extern SCM scm_seed_to_random_state (SCM seed);
 121 extern SCM scm_random_uniform (SCM state);
 122 extern SCM scm_random_solid_sphere_x (SCM v, SCM state);
 123 extern SCM scm_random_hollow_sphere_x (SCM v, SCM state);
 124 extern SCM scm_random_normal (SCM state);
 125 extern SCM scm_random_normal_vector_x (SCM v, SCM state);
 126 extern SCM scm_random_exp (SCM state);
 127 extern void scm_init_random (void);
 128
 129 #endif  /* RANDOMH */