1 // ---------------------------------------------------------------------------
2 //
3 // This file is part of PermLib.
4 //
5 // Copyright (c) 2009-2011 Thomas Rehn <thomas@carmen76.de>
6 // All rights reserved.
7 //
8 // Redistribution and use in source and binary forms, with or without
9 // modification, are permitted provided that the following conditions
10 // are met:
11 // 1. Redistributions of source code must retain the above copyright
12 // notice, this list of conditions and the following disclaimer.
13 // 2. Redistributions in binary form must reproduce the above copyright
14 // notice, this list of conditions and the following disclaimer in the
15 // documentation and/or other materials provided with the distribution.
16 // 3. The name of the author may not be used to endorse or promote products
17 // derived from this software without specific prior written permission.
18 //
19 // THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20 // IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21 // OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22 // IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23 // INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24 // NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28 // THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 //
30 // ---------------------------------------------------------------------------
31
32
33 #ifndef PARTITION_VECTOR_STABILIZER_SEARCH_H_
34 #define PARTITION_VECTOR_STABILIZER_SEARCH_H_
35
36 #include <permlib/search/partition/r_base.h>
37 #include <permlib/predicate/vector_stabilizer_predicate.h>
38 #include <permlib/search/partition/set_stabilize_refinement.h>
39 #include <permlib/search/partition/refinement_family.h>
40
41 namespace permlib {
42 namespace partition {
43
44 /// subgroup search for a stabilizer of an integer vector based on partition backtracking
45 template<class BSGSIN,class TRANSRET>
46 class VectorStabilizerSearch : public RBase<BSGSIN,TRANSRET> {
47 public:
48 typedef typename RBase<BSGSIN,TRANSRET>::PERM PERM;
49
50 /// constructor
51 /**
52 * @param bsgs BSGS of group
53 * @param pruningLevelDCM level up to which expensive double coset minimality pruning is performed; zero to disable
54 */
55 VectorStabilizerSearch(const BSGSIN& bsgs, unsigned int pruningLevelDCM);
56
57 /// initializes search
58 /**
59 * assume that integer vector has entries 0, 1, ..., maxEntries-1
60 * @param begin iterator(unsigned long) begin of the integer vector to be stabilized
61 * @param end iterator(unsigned long) end of the integer vector to be stabilized
62 * @param maxEntries value of maximal entry of integer vector plus 1
63 */
64 template<class InputIterator>
65 void construct(InputIterator begin, InputIterator end, unsigned int maxEntries);
66 protected:
67 virtual unsigned int processNewFixPoints(const Partition& pi, unsigned int backtrackCount);
68 private:
69 std::vector<unsigned int> toStab;
70 unsigned int m_maxEntries;
71 };
72
73 template<class BSGSIN,class TRANSRET>
VectorStabilizerSearch(const BSGSIN & bsgs,unsigned int pruningLevelDCM)74 VectorStabilizerSearch<BSGSIN,TRANSRET>::VectorStabilizerSearch(const BSGSIN& bsgs, unsigned int pruningLevelDCM)
75 : RBase<BSGSIN,TRANSRET>(bsgs, pruningLevelDCM)
76 { }
77
78 template<class BSGSIN,class TRANSRET>
79 template<class InputIterator>
construct(InputIterator begin,InputIterator end,unsigned int maxEntries)80 void VectorStabilizerSearch<BSGSIN,TRANSRET>::construct(InputIterator begin, InputIterator end, unsigned int maxEntries) {
81 VectorStabilizerPredicate<PERM>* stabPred = new VectorStabilizerPredicate<PERM>(begin, end);
82 m_maxEntries = maxEntries;
83 toStab.insert(toStab.begin(), begin, end);
84 std::vector<unsigned int> stabC(toStab.size());
85
86 #ifdef PERMLIB_DEBUGMODE
87 BOOST_FOREACH(const unsigned int v, stabC) {
88 BOOST_ASSERT( v < maxEntries );
89 }
90 #endif
91
92 // we can ignore the highest entries because these are automatically stabilized
93 // if all other entries are stabilized
94 for (unsigned int c = 0; c < maxEntries - 1; ++c) {
95 unsigned int i = 0;
96 std::vector<unsigned int>::iterator stabIt = toStab.begin(), cIt = stabC.begin();
97 for (; stabIt != toStab.end(); ++stabIt) {
98 BOOST_ASSERT( cIt != stabC.end() );
99 if (*stabIt == c)
100 *cIt++ = i;
101 ++i;
102 }
103 SetStabilizeRefinement<PERM> ssr(this->m_bsgs.n, stabC.begin(), cIt);
104 ssr.initializeAndApply(this->m_partition);
105 PERM empty(this->m_bsgs.n);
106 ssr.apply2(this->m_partition2, empty);
107 }
108 RBase<BSGSIN,TRANSRET>::construct(stabPred, 0);
109 }
110
111 template<class BSGSIN,class TRANSRET>
processNewFixPoints(const Partition & pi,unsigned int level)112 unsigned int VectorStabilizerSearch<BSGSIN,TRANSRET>::processNewFixPoints(const Partition& pi, unsigned int level) {
113 const unsigned int basePos = RBase<BSGSIN,TRANSRET>::processNewFixPoints(pi, level);
114 if (!this->m_limitInitialized) {
115 bool allFound = true;
116 int pos = -1;
117 BOOST_FOREACH(unsigned int alpha, toStab) {
118 ++pos;
119 if (alpha == m_maxEntries - 1)
120 continue;
121 if (std::find(pi.fixPointsBegin(), pi.fixPointsEnd(), static_cast<unsigned int>(pos)) == pi.fixPointsEnd()) {
122 allFound = false;
123 break;
124 }
125 }
126 if (allFound) {
127 this->m_limitLevel = level;
128 this->m_limitBase = basePos;
129 this->m_limitInitialized = true;
130 }
131 }
132 return basePos;
133 }
134
135 }
136 }
137
138 #endif // -- PARTITION_VECTOR_STABILIZER_SEARCH_H_
139