permlib  0.2.6
Library for permutation computations
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include/permlib/sorter/group_sorter.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 GROUPSORTER_H
00034 #define GROUPSORTER_H
00035 
00036 #include <boost/foreach.hpp>
00037 
00038 namespace permlib {
00039 
00041 template <class PERM>
00042 class GroupSorter : public std::binary_function<PERM, PERM, bool>{
00043 public:
00045 
00050         template <class InputIterator>
00051         GroupSorter(unsigned int size, InputIterator begin, InputIterator end) :
00052                 // initialize m_size elements with value m_size
00053                 m_order(size, size),
00054                 m_base(begin, end)
00055         {
00056                 InputIterator it;
00057                 unsigned int i = 0;
00058                 // base elements first
00059                 for (it = begin; it != end; ++it) {
00060                         m_order[*it] = ++i;
00061                 }
00062         }
00063 
00065         bool operator() (PERM a, PERM b) const {
00066                 BOOST_FOREACH(unsigned long beta, m_base) {
00067                         if (m_order[a / beta] < m_order[b / beta])
00068                                 return true;
00069                 }
00070                 return false;
00071         }
00072 private:
00073         std::vector<unsigned long> m_order;
00074         std::vector<unsigned long> m_base;
00075 };
00076 
00077 }
00078 
00079 #endif // -- GROUPSORTER_H