src/util.cpp

   1 /*  Copyright (C) 2006-2008  Joris Mooij  [j dot mooij at science dot ru dot nl]
   2     Radboud University Nijmegen, The Netherlands
   3
   4     This file is part of libDAI.
   5
   6     libDAI is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  10
  11     libDAI is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License
  17     along with libDAI; if not, write to the Free Software
  18     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19 */
  20
  21
  22 #include <dai/util.h>
  23 #include <boost/random/linear_congruential.hpp>
  24 #include <boost/random/uniform_real.hpp>
  25 #include <boost/random/normal_distribution.hpp>
  26 #include <boost/random/variate_generator.hpp>
  27
  28
  29 namespace dai {
  30
  31
  32 clock_t toc() {
  33     tms tbuf;
  34     times(&tbuf);
  35     return( tbuf.tms_utime );
  36 }
  37
  38
  39 // This is a typedef for a random number generator.
  40 // Try boost::mt19937 or boost::ecuyer1988 instead of boost::minstd_rand
  41 typedef boost::minstd_rand _rnd_gen_type;
  42
  43 _rnd_gen_type _rnd_gen(42);
  44
  45 // Define a uniform random number distribution which produces "double"
  46 // values between 0 and 1 (0 inclusive, 1 exclusive).
  47 boost::uniform_real<> _uni_dist(0,1);
  48 boost::variate_generator<_rnd_gen_type&, boost::uniform_real<> > _uni_rnd(_rnd_gen, _uni_dist);
  49
  50 // Define a normal distribution with mean 0 and standard deviation 1.
  51 boost::normal_distribution<> _normal_dist;
  52 boost::variate_generator<_rnd_gen_type&, boost::normal_distribution<> > _normal_rnd(_rnd_gen, _normal_dist);
  53
  54
  55 void rnd_seed( int seed ) {
  56     _rnd_gen.seed(seed);
  57 }
  58
  59 double rnd_uniform() {
  60     return _uni_rnd();
  61 }
  62
  63 double rnd_stdnormal() {
  64     return _normal_rnd();
  65 }
  66
  67
  68 } // end of namespace dai