linbox
examples/sparseelimdet.C

Gaussian elimination determinant of sparse matrix over Z or Zp.

/* -*- mode: C++; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
// vim:sts=8:sw=8:ts=8:noet:sr:cino=>s,f0,{0,g0,(0,\:0,t0,+0,=s
/*
 * examples/sparseelimdet.C
 *
 * Copyright (C) 2006, 2010  J-G Dumas
 *
 * This file is part of 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 of
 *   the License, or (at your option) any later version.
 *
 *   LinBox 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 LinBox.  If not, see
 *   <http://www.gnu.org/licenses/>.
 */

//#include "linbox-config.h"

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

#include "linbox/field/modular.h"
#include "linbox/field/gf2.h"
#include "linbox/blackbox/sparse.h"
#include "linbox/blackbox/zero-one.h"
#include "linbox/solutions/rank.h"
#include "linbox/solutions/det.h"
#include "linbox/util/matrix-stream.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.

        PID_integer ZZ;
        PID_integer::Element d;
        MatrixStream<PID_integer> ms( ZZ, input );
        SparseMatrix<PID_integer, Vector<PID_integer>::SparseSeq > A ( ms );
        cout << "A is " << A.rowdim() << " by " << A.coldim() << endl;

        SE.strategy(Specifier::PIVOT_LINEAR);
        det (d, A, SE);

        ZZ.write(cout << "Determinant is ", d) << endl;
    }
    if (argc == 3) {
        double q = atof(argv[2]);
        typedef Modular<double> Field;
        Field::Element d;
        Field F(q);
        MatrixStream<Field> ms( F, input );
        SparseMatrix<Field, Vector<Field>::SparseSeq > B (ms);
        cout << "B is " << B.rowdim() << " by " << B.coldim() << endl;
        if (B.rowdim() <= 20 && B.coldim() <= 20) B.write(cout) << endl;


        SE.strategy(Specifier::PIVOT_NONE);
        // using Sparse Elimination
        det (d, B, SE);
        if (B.rowdim() <= 20 && B.coldim() <= 20) B.write(cout) << endl;
        F.write(cout << "Determinant is ", d) << endl;

        SE.strategy(Specifier::PIVOT_LINEAR);
        // using Sparse Elimination with reordering
        detin (d, B, SE);
        if (B.rowdim() <= 20 && B.coldim() <= 20) B.write(cout) << endl;
        F.write(cout << "Determinant is ", d) << endl;


    }

    return 0;
}