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 REDUNDANT_BASE_POINT_INSERTION_STRATEGY_H_ 00034 #define REDUNDANT_BASE_POINT_INSERTION_STRATEGY_H_ 00035 00036 namespace permlib { 00037 00038 template <class PERM, class TRANS> 00039 struct BSGS; 00040 00042 template <class PERM, class TRANS> 00043 class RedundantBasePointInsertionStrategy { 00044 public: 00046 00049 RedundantBasePointInsertionStrategy(const BSGS<PERM,TRANS> &bsgs) : m_bsgs(bsgs) {} 00050 00051 // virtual destructor 00052 virtual ~RedundantBasePointInsertionStrategy() {} 00053 00055 00060 virtual int findInsertionPoint(dom_int beta, std::list<typename PERM::ptr> &S_i) const = 0; 00061 protected: 00063 const BSGS<PERM,TRANS> &m_bsgs; 00064 }; 00065 00067 template <class PERM, class TRANS> 00068 class TrivialRedundantBasePointInsertionStrategy : public RedundantBasePointInsertionStrategy<PERM,TRANS> { 00069 public: 00071 TrivialRedundantBasePointInsertionStrategy(const BSGS<PERM,TRANS> &bsgs) : RedundantBasePointInsertionStrategy<PERM,TRANS>(bsgs) {} 00072 00073 virtual int findInsertionPoint(dom_int beta, std::list<typename PERM::ptr> &S_i) const { 00074 const std::vector<dom_int> &B = RedundantBasePointInsertionStrategy<PERM,TRANS>::m_bsgs.B; 00075 const std::vector<TRANS> &U = RedundantBasePointInsertionStrategy<PERM,TRANS>::m_bsgs.U; 00076 for (unsigned int i=0; i<B.size(); ++i) { 00077 if (beta == B[i]) 00078 return -i-1; 00079 } 00080 int pos = B.size(); 00081 while (pos > 0 && U[pos-1].size() == 1) 00082 --pos; 00083 return pos; 00084 } 00085 }; 00086 00088 template <class PERM, class TRANS> 00089 class FirstRedundantBasePointInsertionStrategy : public RedundantBasePointInsertionStrategy<PERM,TRANS> { 00090 public: 00092 FirstRedundantBasePointInsertionStrategy(const BSGS<PERM,TRANS> &bsgs) : RedundantBasePointInsertionStrategy<PERM,TRANS>(bsgs) {} 00093 00094 virtual int findInsertionPoint(dom_int beta, std::list<typename PERM::ptr> &S_i) const { 00095 const std::vector<dom_int> &B = RedundantBasePointInsertionStrategy<PERM,TRANS>::m_bsgs.B; 00096 const std::list<typename PERM::ptr> &S = RedundantBasePointInsertionStrategy<PERM,TRANS>::m_bsgs.S; 00097 typename std::vector<dom_int>::const_iterator bIt = B.begin(); 00098 int pos = B.size(); 00099 for (unsigned int i=0; i<B.size(); ++i) { 00100 if (beta == B[i]) 00101 return -i-1; 00102 00103 ++bIt; 00104 const PointwiseStabilizerPredicate<PERM> stab_i(B.begin(), bIt); 00105 S_i.clear(); 00106 00107 //TODO: don't create temporary copy 00108 // place directly into predicate 00109 std::copy_if(S.begin(), S.end(), std::back_inserter(S_i), stab_i); 00110 00111 StabilizesPointPredicate<PERM> stab_beta(S_i.begin(), S_i.end()); 00112 if (stab_beta(beta)) { 00113 pos = i+1; 00114 break; 00115 } 00116 } 00117 return pos; 00118 } 00119 }; 00120 00121 } 00122 00123 #endif // -- REDUNDANT_BASE_POINT_INSERTION_STRATEGY_H_