EvtRandom.cpp

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* Copyright 1998-2020 CERN for the benefit of the EvtGen authors       *
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* This file is part of EvtGen.                                         *
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* EvtGen 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.                                  *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        *
* GNU General Public License for more details.                         *
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#include "EvtGenBase/EvtRandom.hh"
 
#include "EvtGenBase/EvtConst.hh"
#include "EvtGenBase/EvtRandomEngine.hh"
#include "EvtGenBase/EvtReport.hh"
 
#include <iostream>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
 
using std::endl;
 
thread_local EvtRandomEngine* EvtRandom::m_randomEngine = nullptr;
 
void EvtRandom::setRandomEngine( EvtRandomEngine* randomEngine )
{
    m_randomEngine = randomEngine;
}
 
double EvtRandom::random()
{
    if ( m_randomEngine == nullptr ) {
        EvtGenReport( EVTGEN_ERROR, "EvtGen" )
            << "No random engine available in "
            << "EvtRandom::random()." << endl;
        ::abort();
    }
 
    return m_randomEngine->random();
}
 
void EvtRandom::setSeed( unsigned long int seed )
{
    if ( m_randomEngine == nullptr ) {
        EvtGenReport( EVTGEN_ERROR, "EvtGen" )
            << "No random engine available in "
            << "EvtRandom::random()." << endl;
        ::abort();
    }
 
    m_randomEngine->setSeed( seed );
}
 
unsigned long int EvtRandom::lastSeed()
{
    if ( m_randomEngine == nullptr ) {
        EvtGenReport( EVTGEN_ERROR, "EvtGen" )
            << "No random engine available in "
            << "EvtRandom::random()." << endl;
        ::abort();
    }
 
    return m_randomEngine->lastSeed();
}
 
// Random number routine to generate numbers between
// min and max.  By djl on July 27, 1995.
double EvtRandom::Flat( double min, double max )
{
    if ( min > max ) {
        EvtGenReport( EVTGEN_ERROR, "EvtGen" )
            << "min>max in EvtRandom::Flat(" << min << "," << max << ")" << endl;
        ::abort();
    }
 
    return EvtRandom::random() * ( max - min ) + min;
}
 
double EvtRandom::Flat( double max )
{
    return max * EvtRandom::random();
}
 
double EvtRandom::Flat()
{
    return EvtRandom::random();
}
 
double EvtRandom::Gaussian()
{
    double x = EvtRandom::random();
    double y = EvtRandom::random();
 
    return cos( x * EvtConst::twoPi ) * sqrt( -2.0 * log( 1 - y ) );
}