PARP Research Group

Universidad de Murcia

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src/qvmath/qvpermutation.cpp Go to the documentation of this file. /* * Copyright (C) 2007, 2008, 2009, 2010, 2011, 2012. PARP Research Group. * <http://perception.inf.um.es> * University of Murcia, Spain. * * This file is part of the QVision library. * * QVision 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, version 3 of the License. * * QVision 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 QVision. If not, see <http://www.gnu.org/licenses/>. */ #include <QString> #include <QVVector> #include <QVMatrix> #include <QVPermutation> bool QVPermutation::checkConsistency() const { QVector<bool> check(size(), false); //bool check[size()]; //for(int i=0;i<size();i++) // check[i] = false; for(int i=0;i<size();i++) { if( (operator[](i) < 0) or (operator[](i) >= size()) ) return FALSE; check[operator[](i)] = true; } for(int i=0;i<size();i++) if(not check[i]) return FALSE; return TRUE; } QVMatrix QVPermutation::toMatrix() const { if(not checkConsistency()) qFatal("Inconsistent QVPermutation in QVPermutation::toMatrix()"); QVMatrix result(size(),size(),0.0); for(int i=0;i<size();i++) result(i,operator[](i)) = 1.0; return result; } int QVPermutation::signature() const { int p=0, n=size(); QVector<bool> v(n, false); //bool v[n]; //for(int j=0;j<n;j++) // v[j] = false; for(int j=0;j<n;j++) { if(v[j]) ++p; else { int x = j; do { x = operator[](x); v[x] = true; } while (x != j); } } if(p&1) return -1; else return +1; } QVPermutation QVPermutation::fromMatrix(const QVMatrix &matrix) { const int m=matrix.getRows(); # ifndef QT_NO_DEBUG const int n=matrix.getCols(); # endif Q_ASSERT(m == n); QVPermutation perm(m); for(int i=0;i<m;i++) perm[i] = matrix.getRow(i).maxIndex(); if(not perm.checkConsistency()) qFatal("QVPermutation::fromMatrix() called with matrix where the position of the maximum elements in each row do not generate a permutation matrix"); return perm; } std::ostream& operator << ( std::ostream &os, const QVPermutation &vector ) { const int size = vector.size(); os << "QVPermutation (" << size << ") [ "; for (int i = 0; i < size; i++) os << qPrintable(QString("%1").arg(vector[i])) << " "; os << "]"; return os; }

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