olbalgorithms.cpp

open lattice boltzmann project www.openlb.org

/*  This file is part of the OpenLB library
 *
 *  Copyright (C) 2008 Jonas Latt
 *  Address: Rue General Dufour 24,  1211 Geneva 4, Switzerland 
 *  E-mail: [e-mail]
 *
 *  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., 51 Franklin Street, Fifth Floor,
 *  Boston, MA  02110-1301, USA.
*/

#include "olbAlgorithms.h"

namespace olb {

namespace algorithm {

std::vector<int> primeFactor(int value) {
    std::vector<int> primeFactors;
    int testFactor = 2;
    while (testFactor <= value) {
        if (value%testFactor==0) {
            value /= testFactor;
            primeFactors.push_back(testFactor);
        }
        else {
            ++testFactor;
        }
    }
    return primeFactors;
}

std::vector<int> evenRepartition(int value, int d) {
    std::vector<int> primeFactors = primeFactor(value);
    std::vector<int> repartition(d);
    for (int iRep=0; iRep<d; ++iRep) {
        repartition[iRep] = 1;
    }
    int iDim=0;
    for (int iPrime=(int)(primeFactors.size()-1); iPrime>=0; --iPrime) {
        repartition[iDim] *= primeFactors[iPrime];
        iDim = (iDim+1)%d;
    }
    return repartition;
}

}

}