Sacado_RandomImp.hpp

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// $Id$ 
// $Source$ 
// @HEADER
// ***********************************************************************
// 
//                           Sacado Package
//                 Copyright (2006) Sandia Corporation
// 
// Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation,
// the U.S. Government retains certain rights in this software.
// 
// This library is free software; you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation; either version 2.1 of the
// License, or (at your option) any later version.
//  
// This library 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
// Lesser General Public License for more details.
//  
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
// USA
// Questions? Contact David M. Gay (dmgay@sandia.gov) or Eric T. Phipps
// (etphipp@sandia.gov).
// 
// ***********************************************************************
// @HEADER

#include <cmath>
#include <cstdlib>
#include <iostream>
#include <cstdlib>

template <typename ScalarT>
Sacado::Random<ScalarT>::
Random() :
  a(0.0),
  b(1.0),
  seed(static_cast<ScalarT>(rand()))
{
  // rand() can return 0 or 2147483647, so adjust seed if that happens
  if ((seed == 0.0) || (seed == 2147483647.0))
    seed = 1.0;
}

template <typename ScalarT>
Sacado::Random<ScalarT>::
Random(ScalarT a_, ScalarT b_) :
  a(a_),
  b(b_),
  seed(static_cast<ScalarT>(rand()))
{
  // rand() can return 0 or 2147483647, so adjust seed if that happens
  if ((seed == 0.0) || (seed == 2147483647.0))
    seed = 1.0;
}

template <typename ScalarT>
Sacado::Random<ScalarT>::
Random(ScalarT a_, ScalarT b_, int s) :
  a(a_),
  b(b_),
  seed(0.0)
{
  setSeed(s);
}

template <typename ScalarT>
Sacado::Random<ScalarT>::
~Random()
{
}

template <typename ScalarT>
void
Sacado::Random<ScalarT>::
setSeed(int s) {
  int ss = checkSeed("setSeed", s);
  srand(ss);
  seed = static_cast<ScalarT>(s);
}

template <typename ScalarT>
ScalarT
Sacado::Random<ScalarT>::
number() {
  const ScalarT A = 16807.0;
  const ScalarT bigInt = 2147483647.0;
      
  seed = std::fmod(A*seed, bigInt);
  return (b-a)*(seed/bigInt) + a;
}

template <typename ScalarT>
int
Sacado::Random<ScalarT>::
checkSeed(const std::string& func, int s) {
  if ((s < 1) || (s > 2147483646)) {
    std::cerr << "Error in Sacado::Random::" << s << "():  " 
        << "supplied seed " 
        << s << " is not an integer between 1 and 2147483646." 
        << std::endl << "Using a seed of 1 instead." << std::endl;
    return 1;
  }
  else
    return s;
}

#ifdef HAVE_SACADO_COMPLEX

template <typename T>
Sacado::Random< std::complex<T> >::
Random() :
  rand_real(0.0, 1.0),
  rand_imag(0.0, 1.0)
{
}

template <typename T>
Sacado::Random< std::complex<T> >::
Random(const std::complex<T>& a, const std::complex<T>& b) :
  rand_real(a.real(), b.real()),
  rand_imag(a.imag(), b.imag())
{
}

template <typename T>
Sacado::Random< std::complex<T> >::
Random(const std::complex<T>& a, const std::complex<T>& b, int s) :
  rand_real(a.real(), b.real(), s),
  rand_imag(a.imag(), b.imag(), s+1)
{
}

template <typename T>
Sacado::Random< std::complex<T> >::
~Random()
{
}

template <typename T>
void
Sacado::Random< std::complex<T> >::
setSeed(int s) {
  rand_real.setSeed(s);
  rand_imag.setSeed(s+1);
}

template <typename T>
std::complex<T>
Sacado::Random< std::complex<T> >::
number() {
  return std::complex<T>(rand_real.number(), rand_imag.number());
}

#endif // HAVE_SACADO_COMPLEX