examples/densesolverat.C

Direct dense solver over the rationals.

Direct dense solver over the rationals

Author

Jean-.nosp@m.Guil.nosp@m.laume.nosp@m..Dum.nosp@m.as@un.nosp@m.iv-g.nosp@m.renob.nosp@m.le-a.nosp@m.lpes..nosp@m.fr

/*
 * examples/densesolverat.C
 *
 * Copyright (C) 2012 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 <iostream>
#include "givaro/modular.h"
 
#include "linbox/matrix/sparse-matrix.h"
#include "linbox/solutions/solve.h"
#include "linbox/util/matrix-stream.h"
#include "linbox/solutions/methods.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 > 4) {
        cerr << "Usage: solve <matrix-file-in-supported-format> [<dense-vector-file>]" << endl;
        return 0;
    }
    std::ifstream input (argv[1]);
    if (!input) { cerr << "Error opening matrix file " << argv[1] << endl; return -1; }
    std::ifstream invect;
 
    bool createB = false;
    if (argc == 2) {
        createB = true;
    }
 
    if (argc == 3) {
        invect.open (argv[2], std::ifstream::in);
        if (!invect) {
            createB = true;
        }
        else {
            createB = false;
        }
    }
 
    {
        typedef Givaro::QField<Givaro::Rational> Rats;
        Rats QQ;
        typedef DenseVector<Rats> RVector;
 
        MatrixStream<Rats> ms( QQ, input );
        DenseMatrix<Rats> A ( ms );
        std::cout << "A is " << A.rowdim() << " by " << A.coldim() << std::endl;
 
        RVector X(QQ, A.coldim()),B(QQ, A.rowdim());
 
        if (createB) {
            cerr << "Creating a random {-1,1} vector " << endl;
            for(auto it=B.begin(); it != B.end(); ++it)
                if (drand48() <0.5)
                    *it = -1;
                else
                    *it = 1;
        } else {
            for(auto&& it:B) invect >> it;
            invect.close();
        }
 
        std::cout << "B is [";
        for(auto it:B) QQ.write(cout, it) << ' ';
        std::cout << ']' << std::endl;
 
        Timer chrono;
 
            // DenseElimination dense
        std::cout << "DenseElimination" << std::endl;
        chrono.start();
        solve (X, A, B, Method::DenseElimination());
        chrono.stop();
 
        std::cout << "(DenseElimination) Solution is [";
        for(auto it:X) QQ.write(cout, it) << " ";
        std::cout << ']' << std::endl;
 
        std::cout << "CPU time (seconds): " << chrono.usertime() << std::endl;
 
 
    }
 
    return 0;
}
 
// Local Variables:
// mode: C++
// tab-width: 4
// indent-tabs-mode: nil
// c-basic-offset: 4
// End:
// vim:sts=4:sw=4:ts=4:et:sr:cino=>s,f0,{0,g0,(0,\:0,t0,+0,=s