permlib  0.2.6
Library for permutation computations
 All Classes Functions Variables Typedefs Enumerations Friends
include/permlib/change/base_change.h
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 BASECHANGE_H_
00034 #define BASECHANGE_H_
00035 
00036 #include <permlib/predicate/pointwise_stabilizer_predicate.h>
00037 
00038 namespace permlib {
00039 
00041 
00045 template<class PERM,class TRANS>
00046 class BaseChange {
00047 public:
00049     BaseChange() : m_statTranspositions(0), m_statScheierGeneratorsConsidered(0) {}
00050         
00052         mutable unsigned int m_statTranspositions;
00053         
00055         mutable unsigned int m_statScheierGeneratorsConsidered;
00056 protected:
00058 
00063         bool isRedundant(const BSGSCore<PERM,TRANS>& bsgs, unsigned int baseTargetPos, unsigned long alpha) const;
00064 };
00065 
00066 template<class PERM,class TRANS>
00067 bool BaseChange<PERM,TRANS>::isRedundant(const BSGSCore<PERM,TRANS>& bsgs, unsigned int baseTargetPos, unsigned long alpha) const {
00068         bool redundant = true;
00069         const PointwiseStabilizerPredicate<PERM> stab_i(bsgs.B.begin(), bsgs.B.begin() + baseTargetPos);
00070         BOOST_FOREACH(const typename PERM::ptr& g, bsgs.S) {
00071                 if (!stab_i(g))
00072                         continue;
00073                 if (*g / alpha != alpha) {
00074                         redundant = false;
00075                         break;
00076                 }
00077         }
00078         
00079 #ifdef PERMLIB_DEBUG_OUTPUT
00080         if (redundant) {
00081                 std::cout << "skip redundant " << (alpha+1) << std::endl;
00082                 print_iterable(bsgs.B.begin(), bsgs.B.begin() + baseTargetPos, 1, " redundant for");
00083         } else {
00084                 std::cout << "look for " << (alpha+1) << " at position " << baseTargetPos << std::endl;
00085         }
00086 #endif
00087 
00088         return redundant;
00089 }
00090 
00091 }
00092 
00093 #endif // -- BASECHANGE_H_