src/matrixmarket/mtxreader0.cpp

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/***************************************************************************
                          mtxreader0.cpp  -  description
                             -------------------
    begin                : Tue Dec 2 2003
    copyright            : (C) 2003 by Roman Geus
    email                : roman.geus@psi.ch
***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   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.                                   *
 *                                                                         *
 ***************************************************************************/

#include <cassert>
#include "Epetra_Map.h"

#include "mtxdataiterator.h"
#include "mtxreader0.h"

MtxReader0::~MtxReader0() {}

Epetra_CrsMatrix* MtxReader0::read() {
    MtxDataIterator it(*_istr, true);

    assert(it.get_element_type() != MtxDataIterator::complex);
    assert(it.get_storage_scheme() == MtxDataIterator::general ||
           it.get_storage_scheme() == MtxDataIterator::symmetric);

    // Allocate map (rows are evenly distributed across processors)
    Epetra_Map range_row_map(it.get_rows(), 0, _comm);

    // Allocate matrix and read matrix data
    Epetra_CrsMatrix* mat = new Epetra_CrsMatrix (Copy, range_row_map, 0);

    // read matrix entries
    while (!it.eof()) {
        MtxDataIterator::Triplet tr = *it;
        int row = tr.row;
        int col = tr.col;
        double val = tr.val;

        if (range_row_map.MyGID(row))
            mat->InsertGlobalValues(row, 1, &val, &col);

        ++it;
    }

    // finalise Crs matrix
    if (it.get_rows() == it.get_cols()) {
        // if square, make sure that row, domain and range map are identical
        mat->FillComplete(range_row_map, range_row_map);
    } else {
        // if not square, only row and range map are identical
        Epetra_Map domain_map(it.get_cols(), 0, _comm);
        mat->FillComplete(domain_map, range_row_map);
    }

    return mat;
}

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