examples/sparseelimdet.C

Gaussian elimination determinant of sparse matrix over Z or Zp.

/*
 * examples/sparseelimdet.C
 *
 * Copyright (C) 2006, 2010  J-G Dumas
 * ========LICENCE========
 * This file is part of the library LinBox.
 *
 * LinBox is free software: you can redistribute it and/or modify
 * it under the terms of the  GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 * ========LICENCE========
 */

#include <linbox/linbox-config.h>

#include <iostream>
#include <vector>
#include <utility>

#include <linbox/ring/modular.h>
#include <linbox/field/gf2.h>
#include <linbox/matrix/sparse-matrix.h>
#include <linbox/blackbox/zero-one.h>
#include <linbox/solutions/rank.h>
#include <linbox/solutions/det.h>

using namespace LinBox;
using namespace std;

int main (int argc, char **argv)
{
    commentator().setMaxDetailLevel (-1);
    commentator().setMaxDepth (-1);
    commentator().setReportStream (std::cerr);

    if (argc < 2 || argc > 3)
    {   cerr << "Usage: sparseelimdet <matrix-file-in-supported-format> [<p>]" << endl; return -1; }

    ifstream input (argv[1]);
    if (!input) { cerr << "Error opening matrix file: " << argv[1] << endl; return -1; }

    Method::SparseElimination SE;

    if (argc == 2) { // determinant over the integers.

        Givaro::ZRing<Integer> ZZ;
        SparseMatrix<Givaro::ZRing<Integer> > A ( ZZ );
        A.read(input);
        cout << "A is " << A.rowdim() << " by " << A.coldim() << endl;

        SE.pivotStrategy = PivotStrategy::Linear;
        Givaro::ZRing<Integer>::Element d;
        det (d, A, SE);

        ZZ.write(cout << "Determinant is ", d) << endl;
    }
    if (argc == 3) { // determinant over a finite field
        typedef Givaro::Modular<double> Field;
        double q = atof(argv[2]);
        Field F(q);
        SparseMatrix<Field> B (F);
        B.read(input);
        cout << "B is " << B.rowdim() << " by " << B.coldim() << endl;
        if (B.rowdim() <= 20 && B.coldim() <= 20) B.write(cout) << endl;

        // using Sparse Elimination
        SE.pivotStrategy = PivotStrategy::None;
        Field::Element d;
        det (d, B, SE);

        if (B.rowdim() <= 20 && B.coldim() <= 20)
            B.write(cout) << endl;
        F.write(cout << "Determinant is ", d) << endl;

        // using Sparse Elimination with reordering
        SE.pivotStrategy = PivotStrategy::Linear;
        detInPlace (d, B, SE);
        if (B.rowdim() <= 20 && B.coldim() <= 20)
            B.write(cout) << endl;
        F.write(cout << "Determinant is ", d) << endl;


    }

    return 0;
}

// Local Variables:
// mode: C++
// tab-width: 4
// indent-tabs-mode: nil
// c-basic-offset: 4
// End:
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