random_numbers.cpp

/*
    PyEO

    Copyright (C) 2003 Maarten Keijzer

    This program 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 2 of the License, or
    (at your option) any later version.

    This program 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 this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include <utils/eoRNG.h>
#include <boost/python.hpp>

using namespace boost::python;

#include <sstream>
#include <boost/python/detail/api_placeholder.hpp>

using namespace boost::python;

namespace eo
{
    eoRng rng(time(0));
}

eoRng& get_rng() { return rng; }
double normal(eoRng& rng) { return rng.normal(); }

std::string rng_to_string(const eoRng& _rng)
{
    std::ostringstream os;
    _rng.printOn(os);
    os << std::ends;
    return os.str();
}


void rng_from_string(eoRng& _rng, std::string s)
{
    std::istringstream is(s);
    _rng.readFrom(is);
}

struct RNG_pickle_suite : boost::python::pickle_suite
{
    static
    boost::python::tuple getstate(const eoRng& _rng)
    {
        return boost::python::make_tuple(str(rng_to_string(_rng)));
    }
    static
    void setstate(eoRng& _rng, boost::python::tuple pickled)
    {
        std::string state = extract<std::string>(pickled[0]);
        rng_from_string(_rng, state);
    }
};

int spin(eoRng& _rng, numeric::array values, double total)
{
   if (total == 0.0)
   {
        unsigned sz = len(values);
        for (unsigned i = 0; i < sz; ++i)
        {
            total += extract<double>(values[i]); //extract?
        }
   }

   double chance = _rng.uniform() * total;

   int i = 0;
   while (chance >= 0.0)
       chance -= extract<double>(values[i++]);

   return --i;
}

void random_numbers()
{
    class_<eoRng, boost::noncopyable>("eoRng", init<uint32_t>())
        .def("flip", &eoRng::flip)
        .def("random", &eoRng::random)
        .def("rand", &eoRng::rand)
        .def("rand_max", &eoRng::rand_max)
        .def("reseed", &eoRng::reseed)
        .def("uniform", &eoRng::uniform)
        .def("normal", normal)
        .def("negexp", &eoRng::negexp)
        .def("to_string", rng_to_string)
        .def("from_string", rng_from_string)
        .def("roulette_wheel", spin)
        .def_pickle(RNG_pickle_suite())
        ;

    def("rng", get_rng, return_value_policy<reference_existing_object>());
}

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