mirror of
https://github.com/triqs/dft_tools
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78 lines
2.5 KiB
C++
78 lines
2.5 KiB
C++
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/*******************************************************************************
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*
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* TRIQS: a Toolbox for Research in Interacting Quantum Systems
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*
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* Copyright (C) 2011 by M. Ferrero, O. Parcollet
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*
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* TRIQS is free software: you can redistribute it and/or modify it under the
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* terms of the GNU General Public License as published by the Free Software
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* Foundation, either version 3 of the License, or (at your option) any later
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* version.
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*
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* TRIQS is distributed in the hope that it will be useful, but WITHOUT ANY
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* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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* details.
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*
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* You should have received a copy of the GNU General Public License along with
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* TRIQS. If not, see <http://www.gnu.org/licenses/>.
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*
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******************************************************************************/
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#ifndef POLYMORPH_RANDOM_GENERATOR_H
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#define POLYMORPH_RANDOM_GENERATOR_H
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#include <boost/scoped_ptr.hpp>
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#include "../utility/exceptions.hpp"
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#include "./generator.hpp"
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#include "math.h"
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#include <string>
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namespace triqs {
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namespace mc_tools {
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/**
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* This is a random generator that take the name of the random generator at construct
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* and serve random numbers, buffered with a version boost::generator ,
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* to hide the cost of dynamical polymorphism.
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*/
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class random_generator {
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boost::shared_ptr<void> rng_ptr;
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boost::scoped_ptr< boost::generator <double> > gen;
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std::string name;
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void operator = ( random_generator const & p); //forbid
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std::size_t seed;
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public:
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/// Takes the boost name of the generator e.g. mt19937,...
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random_generator(std::string const & RandomGeneratorName, std::size_t seed_ );
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///
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random_generator( random_generator const & p);
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/// Return a list of the names of available generators, with separator sep
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static std::string random_generator_names(std::string const & sep=" ");
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/// Returns a integer in [0,i-1] with flat distribution
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#define INTEGER_OVERLOAD(T) T operator()(T i) { return (i==1 ? 0 : T(floor(i*((*gen)()))));}
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INTEGER_OVERLOAD(int)
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INTEGER_OVERLOAD(size_t)
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#undef INTEGER_OVERLOAD
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/// Returns a double in [0,1[ with flat distribution
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double operator()() { return ((*gen)());}
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/// Returns a double in [0,x[ with flat distribution
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double operator()(double x) { return x*((*gen)());}
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/// Returns a double in [a,b[ with flat distribution
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double operator()(double a, double b) { assert (b>a); return a + (b-a)*((*gen)());}
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};
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}
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}
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#endif
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