FlagAcceptReject.h

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/*
 * FlagAcceptReject.h
 *
 * Copyright 2016 Antonio Augusto Alves Junior
 *  
 * Created on : 29/03/2016
 *      Author: Antonio Augusto Alves Junior
 */
 
/*
    This file is part of MCBooster.

    MCBooster 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 3 of the License, or
    (at your option) any later version.

    MCBooster 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 MCBooster.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef FLAGACCEPTEDREJECTED_H_
#define FLAGACCEPTEDREJECTED_H_



#include <mcbooster/Config.h>
#include <thrust/random.h>
#include <mcbooster/GTypes.h>

namespace MCBooster
{
struct FlagAcceptReject
{

    GReal_t wmax; 

    FlagAcceptReject(const GReal_t _wmax) :
        wmax(_wmax)
    {   }

    __host__      __device__ GUInt_t hash(GUInt_t a)
    {
        a = (a + 0x7ed55d16) + (a << 12);
        a = (a ^ 0xc761c23c) ^ (a >> 19);
        a = (a + 0x165667b1) + (a << 5);
        a = (a + 0xd3a2646c) ^ (a << 9);
        a = (a + 0xfd7046c5) + (a << 3);
        a = (a ^ 0xb55a4f09) ^ (a >> 16);
        return a;
    }
    __host__ __device__ GBool_t operator ()(GLong_t idx, GReal_t weight)
    {
        GUInt_t seed = hash(idx+68464654684);
        thrust::default_random_engine randEng(seed);
        thrust::uniform_real_distribution<GReal_t> uniDist(0.0, wmax);


        GBool_t flag = (uniDist(randEng) < weight) ? 1 : 0;
        return flag;

    }

};
}



#endif /* FLAGACCEPTEDREJECTED_H_ */