linbox
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Compute the integer characteristic polynomial of symetric matrices with (0,1) coefficients. Example for Pr G. Royle.
/* -*- mode: C++; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */ // vim:sts=8:sw=8:ts=8:noet:sr:cino=>s,f0,{0,g0,(0,\:0,t0,+0,=s /* * examples/graph-charpoly.C * * Copyright (C) 2005, 2007, 2010 C. Pernet * * This file is part of 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 of * the License, or (at your option) any later version. * * LinBox 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 LinBox. If not, see * <http://www.gnu.org/licenses/>. */ #include <iostream> #include "linbox/blackbox/zero-one.h" #include "linbox/field/PID-integer.h" #include "linbox/solutions/charpoly.h" #include "linbox/ring/givaro-polynomial.h" #include "linbox/solutions/methods.h" using namespace std; using namespace LinBox; template <class Field, class Polynomial> void printPolynomial(const Field& F, const Polynomial& P) { int n= (int) P.size()-1; for (int i=0;i<n;++i) cout<<P[i]<<" "; cout<<endl; if (n==1){ cout<<"X"; if ( P[0] != 0) F.write(cout<<((P[0]>0)?"+":""),P[0]); } else{ cout<<"X^"<<n; for ( int i=n-1; i>1; --i) if (!F.isZero(P[i])) F.write(cout<<((P[i]>0)?"+":""),P[i])<<"*X^"<<i; if ( P[1] != 0) F.write(cout<<((P[1]>0)?"+":""),P[1])<<"*X"; if ( P[0] != 0) F.write(cout<<((P[0]>0)?"+":""),P[0]); } } typedef ZeroOne<PID_integer> Matrix; typedef GivPolynomialRing<PID_integer,::Givaro::Dense> IntPolRing; int main (int argc, char **argv) { commentator.getMessageClass (BRIEF_REPORT).setMaxDepth (2); commentator.getMessageClass (BRIEF_REPORT).setMaxDetailLevel (Commentator::LEVEL_UNIMPORTANT); if (argc != 2) { cerr << "Usage: graph-charpoly <matrix-file-in-SMS-format>" <<endl; return -1; } ifstream input (argv[1]); if (!input) { cerr << "Error opening matrix file " << argv[1] << endl; return -1; } //UnparametricField<integer> ZZ; PID_integer ZZ; Matrix A(ZZ); A.read (input); commentator.report(1, BRIEF_REPORT)<< "A is " << A.rowdim() << " by " << A.coldim() << endl; IntPolRing::Element c_A; charpoly (c_A, A, Method::Blackbox(Method::Wiedemann( Specifier::SYMMETRIC))); cout<< "Characteristic Polynomial is "; printPolynomial (ZZ, c_A); return 0; }