/*
 * examples/det.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========
 */

/**\file examples/det.C examples/det.C
 * @example  examples/det.C
  \brief Determinant of sparse matrix over Z or Zp.
  \ingroup examples
  */

#include <linbox/linbox-config.h>
#include <iostream>

#include <linbox/ring/modular.h>
#include <linbox/matrix/sparse-matrix.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 <= 1 || argc > 3) {
		cerr << "Usage: det <matrix-file-in-supported-format> [<p>]" << endl;
		return -1;
	}

	if (argc == 2 ) {

		// For a small integer matrix test, do "det data/mat2S".
		// It is a 2 by 2 matrix with determinant = -2.

		typedef Givaro::ZRing<Integer> Integers;
		Integers ZZ;

		ifstream input (argv[1]);
		if (!input)
		{ cerr << "Error opening matrix file " << argv[1] << endl;
			return -1;
		}
		DenseMatrix<Integers> A(ZZ); A.read(input);
		cout << "Matrix is " << A.rowdim() << " by " << A.coldim() << endl;

		Integers::Element det_A;
		det (det_A, A);

		cout << "Determinant is ";
		ZZ.write(cout, det_A) << endl;
	}
	if (argc == 3) {

		typedef Givaro::Modular<double> Field;
		double q = atof(argv[2]);
		Field F(q);

		ifstream input (argv[1]);
		if (!input)
		{ cerr << "Error opening matrix file " << argv[1] << endl;
			return -1;
		}
		SparseMatrix<Field> B (F); B.read(input);
		cout << "Matrix is " << B.rowdim() << " by " << B.coldim() << endl;

		Field::Element det_B;
		det (det_B, B);

		cout << "Determinant is ";
		F.write(cout, det_B) << " mod " << q << 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
