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/*
* examples/nullspacebasis_rat.C
*
* Copyright (C) The LinBox group
* ========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========
*/
/**\file examples/nullspacebasis.C
* @example examples/nullspacebasis.C
\brief NullSpace of sparse matrix over GFq.
\brief nullspace is allocated m \times n.
\ingroup examples
*/
#include <iostream>
#include <givaro/givrational.h>
#include "linbox/matrix/sparse-matrix.h"
#include "linbox/algorithms/gauss.h"
using namespace LinBox;
typedef Givaro::QField<Givaro::Rational> QRat;
typedef MatrixStream<QRat> QMstream;
typedef SparseMatrix<QRat, SparseMatrixFormat::SparseSeq > QSparseMat;
int main (int argc, char **argv)
{
if ((argc != 2) && (argc != 3)) {
std::cerr << "Usage to get a null space basis over Q: <matrix-file-in-SMS-format> [output-file]" << std::endl;
return -1;
}
std::ifstream input (argv[1]);
if (!input) { std::cerr << "Error opening matrix file " << argv[1] << std::endl; return -1; }
QRat QQ;
QMstream ms(QQ, input);
QSparseMat B (ms);
std::cout << "B is " << B.rowdim() << " by " << B.coldim() << std::endl;
SparseMatrix<QRat> NullSpace(QQ,B.coldim(),B.coldim());
GaussDomain<QRat> GD(QQ);
GD.nullspacebasisin(NullSpace, B);
NullSpace.write( std::clog << "X:=", Tag::FileFormat::Maple ) << ';' << std::endl;
if (argc>2) {
std::ofstream output(argv[2]);
NullSpace.write( output, Tag::FileFormat::SMS );
std::clog << "Nullspace basis written in " << argv[2] << std::endl;
}
std::clog << "NullSpace dimensions:" << NullSpace.rowdim() << 'x' << NullSpace.coldim() << 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
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