/* rng/gsl_rng.h

 * 

 * Copyright (C) 1996, 1997, 1998, 1999, 2000, 2004, 2007 James Theiler, Brian Gough

 * 

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 3 of the License, or (at

 * your option) any later version.

 * 

 * This program is distributed in the hope that it will be useful, but

 * WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * General Public License for more details.

 * 

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

 */

#ifndef __GSL_RNG_H__

#define __GSL_RNG_H__

#include <stdlib.h>

#include <gsl/gsl_types.h>

#include <gsl/gsl_errno.h>

#include <gsl/gsl_inline.h>

#undef __BEGIN_DECLS

#undef __END_DECLS

#ifdef __cplusplus

# define __BEGIN_DECLS extern "C" {

# define __END_DECLS }

#else

# define __BEGIN_DECLS /* empty */

# define __END_DECLS /* empty */

#endif

__BEGIN_DECLS

typedef struct

  {

    const char *name;

    unsigned long int max;

    unsigned long int min;

    size_t size;

    void (*set) (void *state, unsigned long int seed);

    unsigned long int (*get) (void *state);

    double (*get_double) (void *state);

  }

gsl_rng_type;

typedef struct

  {

    const gsl_rng_type * type;

    void *state;

  }

gsl_rng;

/* These structs also need to appear in default.c so you can select

   them via the environment variable GSL_RNG_TYPE */

GSL_VAR const gsl_rng_type *gsl_rng_borosh13;

GSL_VAR const gsl_rng_type *gsl_rng_coveyou;

GSL_VAR const gsl_rng_type *gsl_rng_cmrg;

GSL_VAR const gsl_rng_type *gsl_rng_fishman18;

GSL_VAR const gsl_rng_type *gsl_rng_fishman20;

GSL_VAR const gsl_rng_type *gsl_rng_fishman2x;

GSL_VAR const gsl_rng_type *gsl_rng_gfsr4;

GSL_VAR const gsl_rng_type *gsl_rng_knuthran;

GSL_VAR const gsl_rng_type *gsl_rng_knuthran2;

GSL_VAR const gsl_rng_type *gsl_rng_knuthran2002;

GSL_VAR const gsl_rng_type *gsl_rng_lecuyer21;

GSL_VAR const gsl_rng_type *gsl_rng_minstd;

GSL_VAR const gsl_rng_type *gsl_rng_mrg;

GSL_VAR const gsl_rng_type *gsl_rng_mt19937;

GSL_VAR const gsl_rng_type *gsl_rng_mt19937_1999;

GSL_VAR const gsl_rng_type *gsl_rng_mt19937_1998;

GSL_VAR const gsl_rng_type *gsl_rng_r250;

GSL_VAR const gsl_rng_type *gsl_rng_ran0;

GSL_VAR const gsl_rng_type *gsl_rng_ran1;

GSL_VAR const gsl_rng_type *gsl_rng_ran2;

GSL_VAR const gsl_rng_type *gsl_rng_ran3;

GSL_VAR const gsl_rng_type *gsl_rng_rand;

GSL_VAR const gsl_rng_type *gsl_rng_rand48;

GSL_VAR const gsl_rng_type *gsl_rng_random128_bsd;

GSL_VAR const gsl_rng_type *gsl_rng_random128_glibc2;

GSL_VAR const gsl_rng_type *gsl_rng_random128_libc5;

GSL_VAR const gsl_rng_type *gsl_rng_random256_bsd;

GSL_VAR const gsl_rng_type *gsl_rng_random256_glibc2;

GSL_VAR const gsl_rng_type *gsl_rng_random256_libc5;

GSL_VAR const gsl_rng_type *gsl_rng_random32_bsd;

GSL_VAR const gsl_rng_type *gsl_rng_random32_glibc2;

GSL_VAR const gsl_rng_type *gsl_rng_random32_libc5;

GSL_VAR const gsl_rng_type *gsl_rng_random64_bsd;

GSL_VAR const gsl_rng_type *gsl_rng_random64_glibc2;

GSL_VAR const gsl_rng_type *gsl_rng_random64_libc5;

GSL_VAR const gsl_rng_type *gsl_rng_random8_bsd;

GSL_VAR const gsl_rng_type *gsl_rng_random8_glibc2;

GSL_VAR const gsl_rng_type *gsl_rng_random8_libc5;

GSL_VAR const gsl_rng_type *gsl_rng_random_bsd;

GSL_VAR const gsl_rng_type *gsl_rng_random_glibc2;

GSL_VAR const gsl_rng_type *gsl_rng_random_libc5;

GSL_VAR const gsl_rng_type *gsl_rng_randu;

GSL_VAR const gsl_rng_type *gsl_rng_ranf;

GSL_VAR const gsl_rng_type *gsl_rng_ranlux;

GSL_VAR const gsl_rng_type *gsl_rng_ranlux389;

GSL_VAR const gsl_rng_type *gsl_rng_ranlxd1;

GSL_VAR const gsl_rng_type *gsl_rng_ranlxd2;

GSL_VAR const gsl_rng_type *gsl_rng_ranlxs0;

GSL_VAR const gsl_rng_type *gsl_rng_ranlxs1;

GSL_VAR const gsl_rng_type *gsl_rng_ranlxs2;

GSL_VAR const gsl_rng_type *gsl_rng_ranmar;

GSL_VAR const gsl_rng_type *gsl_rng_slatec;

GSL_VAR const gsl_rng_type *gsl_rng_taus;

GSL_VAR const gsl_rng_type *gsl_rng_taus2;

GSL_VAR const gsl_rng_type *gsl_rng_taus113;

GSL_VAR const gsl_rng_type *gsl_rng_transputer;

GSL_VAR const gsl_rng_type *gsl_rng_tt800;

GSL_VAR const gsl_rng_type *gsl_rng_uni;

GSL_VAR const gsl_rng_type *gsl_rng_uni32;

GSL_VAR const gsl_rng_type *gsl_rng_vax;

GSL_VAR const gsl_rng_type *gsl_rng_waterman14;

GSL_VAR const gsl_rng_type *gsl_rng_zuf;

const gsl_rng_type ** gsl_rng_types_setup(void);

GSL_VAR const gsl_rng_type *gsl_rng_default;

GSL_VAR unsigned long int gsl_rng_default_seed;

gsl_rng *gsl_rng_alloc (const gsl_rng_type * T);

int gsl_rng_memcpy (gsl_rng * dest, const gsl_rng * src);

gsl_rng *gsl_rng_clone (const gsl_rng * r);

void gsl_rng_free (gsl_rng * r);

void gsl_rng_set (const gsl_rng * r, unsigned long int seed);

unsigned long int gsl_rng_max (const gsl_rng * r);

unsigned long int gsl_rng_min (const gsl_rng * r);

const char *gsl_rng_name (const gsl_rng * r);

int gsl_rng_fread (FILE * stream, gsl_rng * r);

int gsl_rng_fwrite (FILE * stream, const gsl_rng * r);

size_t gsl_rng_size (const gsl_rng * r);

void * gsl_rng_state (const gsl_rng * r);

void gsl_rng_print_state (const gsl_rng * r);

const gsl_rng_type * gsl_rng_env_setup (void);

INLINE_DECL unsigned long int gsl_rng_get (const gsl_rng * r);

INLINE_DECL double gsl_rng_uniform (const gsl_rng * r);

INLINE_DECL double gsl_rng_uniform_pos (const gsl_rng * r);

INLINE_DECL unsigned long int gsl_rng_uniform_int (const gsl_rng * r, unsigned long int n);

#ifdef HAVE_INLINE

INLINE_FUN unsigned long int

gsl_rng_get (const gsl_rng * r)

{

  return (r->type->get) (r->state);

}

INLINE_FUN double

gsl_rng_uniform (const gsl_rng * r)

{

  return (r->type->get_double) (r->state);

}

INLINE_FUN double

gsl_rng_uniform_pos (const gsl_rng * r)

{

  double x ;

  do

    {

      x = (r->type->get_double) (r->state) ;

    }

  while (x == 0) ;

  return x ;

}

/* Note: to avoid integer overflow in (range+1) we work with scale =

   range/n = (max-min)/n rather than scale=(max-min+1)/n, this reduces

   efficiency slightly but avoids having to check for the out of range

   value.  Note that range is typically O(2^32) so the addition of 1

   is negligible in most usage. */

INLINE_FUN unsigned long int

gsl_rng_uniform_int (const gsl_rng * r, unsigned long int n)

{

  unsigned long int offset = r->type->min;

  unsigned long int range = r->type->max - offset;

  unsigned long int scale;

  unsigned long int k;

  if (n > range || n == 0) 

    {

      GSL_ERROR_VAL ("invalid n, either 0 or exceeds maximum value of generator",

                     GSL_EINVAL, 0) ;

    }

  scale = range / n;

  do

    {

      k = (((r->type->get) (r->state)) - offset) / scale;

    }

  while (k >= n);

  return k;

}

#endif /* HAVE_INLINE */

__END_DECLS

#endif /* __GSL_RNG_H__ */