ran_array.h

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/*
                          Aleph_w
 
  Data structures & Algorithms
  version 2.0.0b
  https://github.com/lrleon/Aleph-w
 
  This file is part of Aleph-w library
 
  Copyright (c) 2002-2026 Leandro Rabindranath Leon
 
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:
 
  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.
 
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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*/
 
/*    This program by D E Knuth is in the public domain and freely copyable
 *    AS LONG AS YOU MAKE ABSOLUTELY NO CHANGES!
 *    It is explained in Seminumerical Algorithms, 3rd edition, Section 3.6
 *    (or in the errata to the 2nd edition --- see
 *        http://www-cs-faculty.stanford.edu/~knuth/taocp.html
 *    in the changes to Volume 2 on pages 171 and following).              */
 
/*    N.B. The MODIFICATIONS introduced in the 9th printing (2002) are
      included here; there's no backwards compatibility with the original. */
 
/*    This version also adopts Brendan McKay's suggestion to
      accommodate naive users who forget to call ran_start(seed).          */
 
/*    If you find any bugs, please report them immediately to
 *                 taocp@cs.stanford.edu
 *    (and you will be rewarded if the bug is genuine). Thanks!            */
 
/************ see the book for explanations and caveats! *******************/
/************ in particular, you need two's complement arithmetic **********/
 
/* the old C calling conventions are used here, for reasons of portability */
 
# ifdef  __cplusplus
extern "C" {
# endif
 
 
 
/* 
   do this before using ran_array 
*/
extern void ran_start(long seed);
 
 
/* the following routines are from exercise 3.6--15 */
/* after calling ran_start, get new randoms by, e.g., "x=ran_arr_next()" */
 
extern long *ran_arr_ptr; /* the next random number, or -1 */
 
extern long ran_arr_cycle(void);
       
#define ran_arr_next() (*ran_arr_ptr >=0 ? *ran_arr_ptr++ : ran_arr_cycle())
 
# ifdef  __cplusplus
}
# endif