Random.h

// ===========================================================================
// Imagine++ Libraries
// Copyright (C) Imagine
// For detailed information: http://imagine.enpc.fr/software
// ===========================================================================

namespace Imagine {


    inline void initRandom(unsigned int s)
    {
        std::srand(s);
        std::rand();        // The first one is strange (Visual 2003)
    }
    inline void initRandom()
    {
        initRandom((unsigned int)std::time(0));
    }
    inline double doubleRandom()
    {
#if (RAND_MAX==0x7fff) // 15 bits? This is really too small!!
        int a = std::rand()<<15;
        int b = std::rand();
        return double(a|b)/((RAND_MAX<<15)|RAND_MAX);
#else
        return double(std::rand())/RAND_MAX;
#endif
    }
    inline int intRandom(int a,int b)
    {
        return int(a+(b-a+.999)*doubleRandom());
    }
    inline unsigned int uintRandom(unsigned int a)
    {
        return (unsigned int)((a+.999)*doubleRandom());
    }
    inline size_t size_tRandom(size_t a)
    {
        return (size_t)((a+.999)*doubleRandom());
    }
    inline double gaussianRandom()
    {
        double x; // 1st draw
        do 
        x=doubleRandom();
        while (x==0);
#ifdef M_PI
        double pi=M_PI;
#else
        double pi=3.1415926535897932384626433832795;
#endif
        return double(std::sqrt(-2*std::log(x))*std::cos(2*pi*doubleRandom()));
    }


}