Dist.h

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// Honeycomb, Copyright (C) 2015 NewGamePlus Inc.  Distributed under the Boost Software License v1.0.
#pragma once

#include "Honey/Math/Alge/Alge.h"
#include "Honey/Math/Alge/Trig.h"
#include "Honey/Math/Random/Gen.h"

namespace honey
{

template<class Real> class Uniform_;
    
template<class Real>
class RandomDist
{
protected:
    typedef typename Numeral<Real>::Real_   Real_;
    typedef typename Real_::DoubleType      Double_;
    typedef typename Double_::Real          Double;
    typedef Alge_<Real>                     Alge;
    typedef Alge_<Double>                   Alge_d;
    typedef Uniform_<Double>                Uniform;

    #define RandomDist_imports()            \
        using typename Super::Real_;        \
        using typename Super::Double_;      \
        using typename Super::Double;       \
        using typename Super::Alge;         \
        using typename Super::Alge_d;       \
        using typename Super::Uniform;      \
        using Super::getGen;                \
    
public:
    RandomDist(optional<RandomGen&> gen = optnull)      : _gen(gen.ptr()) {}

    virtual ~RandomDist()                               {}

    virtual Real next() const                           { return 0; }


    virtual Real pdf(Real x) const                      { mt_unused(x); return 0; }
    

    virtual Real cdf(Real x) const                      { mt_unused(x); return 0; }


    virtual Real cdfComp(Real x) const                  { return 1 - cdf(x); }


    virtual Real cdfInv(Real P) const                   { mt_unused(P); return 0; }
    virtual Real mean() const                           { return 0; }
    virtual Real variance() const                       { return 0; }
    Real stdDev() const                                 { return Alge::sqrt(variance()); }

    void setGen(RandomGen& gen)                         { _gen = &gen; }
    RandomGen& getGen() const                           { assert(_gen, "Must set a random generator"); return *_gen; }

protected:
    Real cdfInvFind(Real P, Real min, Real max, bool discrete = false) const;

private:
    RandomGen* _gen;
};

extern template class RandomDist<Float>;
extern template class RandomDist<Double>;

}