https://hal.archives-ouvertes.fr/hal-02128878
Tip revision: 4201397494d9af8b687117e8ff4d85a8944f5c5a authored by Software Heritage on 11 June 2019, 10:15:02 UTC
hal: Deposit 298 in collection hal
hal: Deposit 298 in collection hal
Tip revision: 4201397
charpoly.C
/* Copyright (c) FFLAS-FFPACK
* ========LICENCE========
* This file is part of the library FFLAS-FFPACK.
*
* FFLAS-FFPACK 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 "fflas-ffpack/fflas-ffpack.h"
/**
* This example computes the characteristic polynomial of a matrix
* over a defined finite field.
*
* Outputs the characteristic polynomial.
*/
int main(int argc, char** argv)
{
if (argc != 3) {
std::cerr << "Usage: charpoly <p> <matrix>" << std::endl;
return -1;
}
int p = atoi(argv[1]);
std::string file = argv[2];
// Creating the finite field Z/pZ (assuming p>2, use Modular<float> for p=2)
typedef Givaro::ModularBalanced<double> F_t;
// Creating polynomial ring
typedef Givaro::Poly1Dom<F_t> PolyRing_t;
typedef PolyRing_t::Element Poly_t;
// Reading the matrix from a file
F_t F(p);
double* A;
size_t m, n;
FFLAS::ReadMatrix(file.c_str(), F, m, n, A);
if (n != m) {
std::cerr << "Input should be a square matrix" << std::endl;
return -1;
}
Poly_t charp(n+1);
PolyRing_t PolyRing(F, 'X');
FFPACK::CharPoly(PolyRing, charp, n, A, n);
PolyRing.write(std::cout, charp) << std::endl;
FFLAS::fflas_delete(A);
return 0;
}
/* -*- mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
// vim:sts=4:sw=4:ts=4:et:sr:cino=>s,f0,{0,g0,(0,\:0,t0,+0,=s