permlib
0.2.6
Library for permutation computations
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00001 // --------------------------------------------------------------------------- 00002 // 00003 // This file is part of PermLib. 00004 // 00005 // Copyright (c) 2009-2011 Thomas Rehn <thomas@carmen76.de> 00006 // All rights reserved. 00007 // 00008 // Redistribution and use in source and binary forms, with or without 00009 // modification, are permitted provided that the following conditions 00010 // are met: 00011 // 1. Redistributions of source code must retain the above copyright 00012 // notice, this list of conditions and the following disclaimer. 00013 // 2. Redistributions in binary form must reproduce the above copyright 00014 // notice, this list of conditions and the following disclaimer in the 00015 // documentation and/or other materials provided with the distribution. 00016 // 3. The name of the author may not be used to endorse or promote products 00017 // derived from this software without specific prior written permission. 00018 // 00019 // THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 00020 // IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 00021 // OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 00022 // IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 00023 // INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 00024 // NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 00025 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 00026 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 00027 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 00028 // THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 00029 // 00030 // --------------------------------------------------------------------------- 00031 00032 00033 #ifndef SYMMETRIC_GROUP_TRANSVERSAL_H_ 00034 #define SYMMETRIC_GROUP_TRANSVERSAL_H_ 00035 00036 #include <boost/iterator/counting_iterator.hpp> 00037 00038 namespace permlib { 00039 00040 template<class PERM> 00041 struct SymmetricGroup; 00042 00044 template<class PERM> 00045 class SymmetricGroupTransversal { 00046 public: 00048 00052 SymmetricGroupTransversal(const SymmetricGroup<PERM>* sg, unsigned int basePos) : symmetricGroup(sg), m_basePos(basePos) {} 00053 00055 PERM* at(unsigned long val) const { 00056 for (unsigned int i=0; i<m_basePos; ++i) { 00057 if ((symmetricGroup->B)[i] == val) 00058 return 0; 00059 } 00060 00061 PERM* p = new PERM(symmetricGroup->B.size()); 00062 p->setTransposition((symmetricGroup->B)[m_basePos],val); 00063 return p; 00064 } 00065 00067 unsigned int size() const { return symmetricGroup->n - m_basePos; } 00068 00069 boost::counting_iterator<unsigned int> begin() const { return boost::counting_iterator<unsigned int>(0); }; 00070 boost::counting_iterator<unsigned int> end() const { return boost::counting_iterator<unsigned int>(symmetricGroup->n-m_basePos ); }; 00071 private: 00072 const SymmetricGroup<PERM>* symmetricGroup; 00073 unsigned int m_basePos; 00074 }; 00075 00076 } 00077 00078 #endif // SYMMETRIC_GROUP_TRANSVERSAL_H_ 00079