UniformRandomGenerator.h

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/*
 * Copyright (C) 2012 by
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 * and
 *   Neuroinformatics and Cognitive Robotics Labs (NICR) at TU Ilmenau, GERMANY
 * All rights reserved.
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#ifndef _MIRA_UNIFORMRANDOMGENERATOR_H_
#define _MIRA_UNIFORMRANDOMGENERATOR_H_

#include <math/RandomGenerator.h>

namespace mira {


// helper to choose correct boost uniform random distribution depending on
// whether the datatype is integral or floating point.
namespace detail {

// workaround for BOOST Bug #6053: https://svn.boost.org/trac/boost/ticket/6053
template <typename T>
class UniformRealBoostWorkaround : public boost::uniform_real<T>
{
    typedef boost::uniform_real<T> Base;
public:

    explicit UniformRealBoostWorkaround(T min_arg = T(0.0),
                                        T max_arg = T(1.0)) :
        Base(min_arg, max_arg) {}

    template<class Engine>
    typename Base::result_type operator()(Engine& eng) const
    {
        // special treatment for min==max, otherwise boost::uniform_real runs into infinite loop (Bug #6053)
        if(this->min()==this->max())
            return this->min();
        else
            return Base::operator()(eng);
    }
};

template <typename T, bool IsInteger> // T is real
struct UniformRandomDistributionHelper {
#if BOOST_VERSION >= 104700
    typedef UniformRealBoostWorkaround<T> type;
#else
    typedef boost::uniform_real<T> type;
#endif
};

template <typename T> // T is integer
struct UniformRandomDistributionHelper<T,true> {
    typedef boost::uniform_int<T> type;
};

template <typename T>
struct UniformRandomDistributionChooser :
    public UniformRandomDistributionHelper<T,std::numeric_limits<T>::is_integer>
{};
}


template <typename T>
class UniformRandomGenerator :
    public RandomGenerator<typename detail::UniformRandomDistributionChooser<T>::type>
{
public:
    MIRA_RANDOM_GENERATOR_COMMON(UniformRandomGenerator, typename detail::UniformRandomDistributionChooser<T>::type)
    explicit UniformRandomGenerator(T vmin=T(0), T vmax=T(1)) :
        Base(Distribution(vmin,vmax)) {}

    void setLimits(T vmin, T vmax) {
        this->distribution() = Distribution(vmin, vmax);
    }
};


} // namespace

#endif