examples/rank.C

Rank of sparse matrix over Z or Zp.

Rank of sparse matrix over Z or Zp.

/*
 * examples/rank.C
 *
 * Copyright (C) 2005, 2010 D. Saunders, 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 <sstream>
#include <givaro/givrational.h>
 
#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/util/matrix-stream.h>
 
#define SP_STOR SparseMatrixFormat::SparseSeq
 
using namespace LinBox;

int main (int argc, char **argv)
{
    commentator().setMaxDetailLevel (-1);
    commentator().setMaxDepth (-1);
    commentator().setReportStream (std::clog);
 
    if (argc < 2 || argc > 3) {
        std::cerr << "Usage: rank <matrix-file-in-supported-format> [<p>]" << std::endl;
        return -1;
    }
 
    std::ifstream input (argv[1]);
    if (!input) {
        std::cerr << "Error opening matrix file: " << argv[1] << std::endl;
        return -1;
    }
 
    size_t r;
 
    Givaro::QField<Givaro::Rational> QQ;
    LinBox::Timer tim ; tim.clear() ; tim.start();
    MatrixStream<Givaro::QField<Givaro::Rational>> ms (QQ, input);
    SparseMatrix<Givaro::QField<Givaro::Rational>, SP_STOR> A ( ms );
 
    tim.stop();
    std::clog << "matrix is " << A.rowdim() << " by " << A.coldim() << " (" << tim << ")" << std::endl;
    tim.clear() ; tim.start();
 
    if (argc == 2) { // rank over the rational numbers.
        /* We could pick a random prime and work mod that prime, But
         * the point here is that the rank function in solutions/
         * handles that issue.  Our matrix here is an integer or
         * rational matrix and our concept is that we are getting the
         * rank of that matrix by some blackbox magic inside linbox.
         */
        LinBox::rank (r, A);
    }
 
    if (argc == 3) { // rank mod a prime
        uint32_t q = atoi(argv[2]);
        if (q == 0) {
                std::cerr << "second argument should be a non-zero integer or missing\n";
                return -1;
        }
        typedef Givaro::Modular<double> Field;
 
        Field F(q);
        if (q > F.maxCardinality()) {
            std::cerr << "your number is too big for this field" << std::endl;
            return -1 ;
        }
 
            // modular image of A
        SparseMatrix<Field, SP_STOR > B (F, A.rowdim(), A.coldim());
        MatrixHom::map(B, A);
        tim.stop();
        std::clog << "matrix is " << B.rowdim() << " by " << B.coldim()
                  <<" (time for map: "<< tim << ")" << std::endl;
 
        tim.clear();tim.start();
//         if (B.rowdim() <= 20 && B.coldim() <= 20)
//             B.write(std::clog) << std::endl;
 
        // Using the adaptive LinBox Solution
        LinBox::rank(r,B);
    }
    tim.stop();
 
    std::clog << "Rank is " << std::flush;
    std::cout << r << std::flush;
    std::clog << " (" << tim << " )" << 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