gpu_random.h

/*
  Copyright (c) 2007 A. Arnold and J. A. van Meel, FOM institute
  AMOLF, Amsterdam; all rights reserved unless otherwise stated.

  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 2 of the License, or
  (at your option) any later version.

  In addition to the regulations of the GNU General Public License,
  publications and communications based in parts on this program or on
  parts of this program are required to cite the article
  "Harvesting graphics power for MD simulations"
  by J.A. van Meel, A. Arnold, D. Frenkel, S. F. Portegies Zwart and
  R. G. Belleman, arXiv:0709.3225.

  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., 59 Temple Place, Suite 330, Boston,
  MA 02111-1307 USA
*/
#ifndef _RANDOM_H_
#define _RANDOM_H_

class RNG_rand48 {
  int stride;

  void *state;
  void *res;

  int  threadsX;
  int  blocksX;

  unsigned int A0, A1, C0, C1;

  static const unsigned long long a = 0x5DEECE66DLL, c = 0xB;

  void init(int seed);
  void cleanup();

  // maximum value of random number
  int rand_max;

public:
  static const unsigned int MAX_RANGE=0x7FFFFFFF;
  
  RNG_rand48(int seed, int _max=0): res(0), rand_max(_max) { init(seed); }
  ~RNG_rand48() { cleanup(); }

  void generate(int n);

  void generate(int n, int n_max);

  void get(int *r, int n);

  void *get_random_numbers() { return res; }

private:
        void generate_int(int n, int n_max, int offset);

};

#endif