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dft_tools/triqs/mc_tools/random_generator.hpp
Olivier Parcollet b2603dcf3a Fix for clang 1y with gcc lib
- add a workaround for a gcc issue in fisrt_include.
- --> make sure that the first include is :
either a triqs lib
or first_include
2014-01-20 10:50:52 +01:00

77 lines
2.5 KiB
C++

/*******************************************************************************
*
* TRIQS: a Toolbox for Research in Interacting Quantum Systems
*
* Copyright (C) 2011 by M. Ferrero, O. Parcollet
*
* TRIQS 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 3 of the License, or (at your option) any later
* version.
*
* TRIQS 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
* TRIQS. If not, see <http://www.gnu.org/licenses/>.
*
******************************************************************************/
#ifndef POLYMORPH_RANDOM_GENERATOR_H
#define POLYMORPH_RANDOM_GENERATOR_H
#include <triqs/utility/first_include.hpp>
#include <boost/scoped_ptr.hpp>
#include "../utility/exceptions.hpp"
#include "./generator.hpp"
#include "math.h"
#include <string>
namespace triqs {
namespace mc_tools {
/**
* This is a random generator that take the name of the random generator at construct
* and serve random numbers, buffered with a version boost::generator ,
* to hide the cost of dynamical polymorphism.
*/
class random_generator {
boost::shared_ptr<void> rng_ptr;
boost::scoped_ptr< boost::generator <double> > gen;
std::string name;
void operator = ( random_generator const & p); //forbid
std::size_t seed;
public:
/// Takes the boost name of the generator e.g. mt19937,...
random_generator(std::string const & RandomGeneratorName, std::size_t seed_ );
///
random_generator( random_generator const & p);
/// Return a list of the names of available generators, with separator sep
static std::string random_generator_names(std::string const & sep=" ");
/// Returns a integer in [0,i-1] with flat distribution
#define INTEGER_OVERLOAD(T) T operator()(T i) { return (i==1 ? 0 : T(floor(i*((*gen)()))));}
INTEGER_OVERLOAD(int)
INTEGER_OVERLOAD(size_t)
#undef INTEGER_OVERLOAD
/// Returns a double in [0,1[ with flat distribution
double operator()() { return ((*gen)());}
/// Returns a double in [0,x[ with flat distribution
double operator()(double x) { return x*((*gen)());}
/// Returns a double in [a,b[ with flat distribution
double operator()(double a, double b) { assert (b>a); return a + (b-a)*((*gen)());}
};
}
}
#endif