MetisPartitioner.cpp

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//=======================================================================================
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//
//  This file is part of VirtualFluids. VirtualFluids 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.
//
//  VirtualFluids 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.
//
//  SPDX-License-Identifier: GPL-3.0-or-later
//  SPDX-FileCopyrightText: Copyright © VirtualFluids Project contributors, see AUTHORS.md in root folder
//
//=======================================================================================
#if defined VF_METIS
 
#include "MetisPartitioner.h"
 
MetisPartitioner::MetisPartitioner()
{
    METIS_SetDefaultOptions(options);
    options[METIS_OPTION_NUMBERING] = 0;
    vsize                           = NULL;
    tpwgts                          = NULL;
    ubvec                           = NULL;
 
    // options[METIS_OPTION_OBJTYPE] = METIS_OBJTYPE_CUT;
 
    // options[METIS_OPTION_CTYPE]  = METIS_CTYPE_SHEM;
    // options[METIS_OPTION_IPTYPE] = METIS_IPTYPE_GROW;
}
idx_t *MetisPartitioner::getMetisOptions() { return options; }
void MetisPartitioner::setMetisOptions(int option, idx_t value) { options[option] = value; }
int MetisPartitioner::partition(int nofParts, MetisPartitioner::PartType ptype)
{
    int rc {0};
    idx_t nvtxs = (idx_t)xadj.size() - 1;     // number of nodes
    idx_t ncon  = (idx_t)vwgt.size() / nvtxs; // number Of node constraints;
    part.resize(nvtxs);
    idx_t edgecutCount  = 0;
    idx_t nofPartsMetis = (idx_t)nofParts;
 
    switch (ptype) {
        case MetisPartitioner::RECURSIVE:
            if (nofParts < 1)
                UB_THROW(UbException(UB_EXARGS, "invalid nofParts<1"));
            else if (nofParts == 1) {
                part.resize(nvtxs, 0);
                return 0;
            }
            // else if( nofParts >  8 ) UBLOG(logWARNING, "MetisPartitioner::Recursive: !!!Warning!!!  best for
            // nofParts<=8 --> Kway is maybe a better option");
 
            rc = METIS_PartGraphRecursive(&nvtxs, &ncon, &xadj[0], &adjncy[0], &vwgt[0], vsize, &adjwgt[0],
                                          &nofPartsMetis, tpwgts, ubvec, options, &edgecutCount, &part[0]);
            break;
        case MetisPartitioner::KWAY:
            if (nofParts < 1)
                UB_THROW(UbException(UB_EXARGS, "invalid nofParts<1"));
            else if (nofParts == 1) {
                part.resize(nvtxs, 0);
                return 0;
            }
            // else if( nofParts <  9 ) UBLOG(logWARNING, "MetisPartitioner::Kway: !!!Warning!!!  best for nofParts>8
            // --> Recursive is maybe a better option");
 
            rc = METIS_PartGraphKway(&nvtxs, &ncon, &xadj[0], &adjncy[0], &vwgt[0], vsize, &adjwgt[0], &nofPartsMetis,
                                     tpwgts, ubvec, options, &edgecutCount, &part[0]);
            break;
    }
 
    switch (rc) {
        case METIS_ERROR_INPUT:
            throw UbException(UB_EXARGS, "METIS: input error");
            break;
        case METIS_ERROR_MEMORY:
            throw UbException(UB_EXARGS, "METIS: it could not allocate the required memory");
            break;
        case METIS_ERROR:
            throw UbException(UB_EXARGS, "METIS: error");
            break;
    }
 
    return edgecutCount;
}
#endif