/cvmfs/atlas.cern.ch/repo/sw/ASG/AnalysisBase/2.4.31/TestTools/TestTools/random.h

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// This file's extension implies that it's C, but it's really -*- C++ -*-.
// $Id$
#ifndef TESTTOOLS_RANDOM_H
#define TESTTOOLS_RANDOM_H


#include <stdint.h>


namespace Athena_test {


static uint32_t rngmax = static_cast<uint32_t> (-1);


uint32_t rng_seed (uint32_t& seed)
{
  seed = (1664525*seed + 1013904223);
  return seed;
}


float randf_seed (uint32_t& seed, float rmax, float rmin = 0)
{
  return static_cast<float>(rng_seed(seed)) / rngmax * (rmax-rmin) + rmin;
}


int randi_seed (uint32_t& seed, int rmax, int rmin = 0)
{
  return static_cast<int> (randf_seed (seed, rmax, rmin));
}


struct RNG
{
  RNG() : seed(1) {}
  int operator() (int n) const { return randi_seed (seed, n); }
  mutable uint32_t seed;
};


struct URNG
{
  typedef uint32_t result_type;
  URNG() : seed(1) {}
  static result_type min() { return 0; }
  static result_type max() { return 1000000; }
  result_type operator()() const { return randi_seed (seed, max()); }
  mutable uint32_t seed;
};


uint32_t seed = 1;
uint32_t rng() { return rng_seed(seed); }
int randi (int rmax, int rmin = 0) { return randi_seed (seed, rmax, rmin); }
float randf (float rmax, float rmin = 0) { return randf_seed (seed, rmax, rmin); }



} // namespace Athena_test


#endif // not TESTTOOLS_RANDOM_H

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