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_SET_IMAGE_SEARCH_H_
34 #define PARTITION_SET_IMAGE_SEARCH_H_
35
36 #include <permlib/search/partition/r_base.h>
37 #include <permlib/predicate/set_image_predicate.h>
38
39 namespace permlib {
40 namespace partition {
41
42 /// coset representative search for a set image based on partition backtracking
43 /**
44 * tries to find a \f$g\f$ such that \f$\Delta^g = \Gamma\f$ for two given sets \f$\Delta,\Gamma\f$
45 */
46 template<class BSGSIN,class TRANSRET>
47 class SetImageSearch : public RBase<BSGSIN,TRANSRET> {
48 public:
49 typedef typename RBase<BSGSIN,TRANSRET>::PERM PERM;
50
51 /// constructor
52 /**
53 * @param bsgs BSGS of group
54 * @param pruningLevelDCM level up to which expensive double coset minimality pruning is performed; zero to disable
55 */
56 SetImageSearch(const BSGSIN& bsgs, unsigned int pruningLevelDCM);
57
58 /// initializes search
59 /**
60 * @param begin iterator(unsigned long) begin of the set \f$\Delta\f$
61 * @param end iterator(unsigned long) end of the set \f$\Delta\f$
62 * @param beginImg iterator(unsigned long) begin of the set \f$\Gamma\f$
63 * @param endImg iterator(unsigned long) end of the set \f$\Gamma\f$
64 */
65 template<class InputIterator>
66 void construct(InputIterator begin, InputIterator end, InputIterator beginImg, InputIterator endImg);
67 protected:
68 virtual unsigned int processNewFixPoints(const Partition& pi, unsigned int backtrackCount);
69 private:
70 std::vector<unsigned long> toStab;
71 };
72
73 template<class BSGSIN,class TRANSRET>
SetImageSearch(const BSGSIN & bsgs,unsigned int pruningLevelDCM)74 SetImageSearch<BSGSIN,TRANSRET>::SetImageSearch(const BSGSIN& bsgs, unsigned int pruningLevelDCM)
75 : RBase<BSGSIN,TRANSRET>(bsgs, pruningLevelDCM, true)
76 { }
77
78 template<class BSGSIN,class TRANSRET>
79 template<class InputIterator>
construct(InputIterator begin,InputIterator end,InputIterator beginImg,InputIterator endImg)80 void SetImageSearch<BSGSIN,TRANSRET>::construct(InputIterator begin, InputIterator end, InputIterator beginImg, InputIterator endImg) {
81 SetImagePredicate<PERM>* stabPred = new SetImagePredicate<PERM>(begin, end, beginImg, endImg);
82 toStab.insert(toStab.begin(), begin, end);
83
84 SetImageRefinement<PERM> sir(RBase<BSGSIN,TRANSRET>::m_bsgs.n, begin, end, beginImg, endImg);
85 sir.initializeAndApply(RBase<BSGSIN,TRANSRET>::m_partition);
86 PERM empty(RBase<BSGSIN,TRANSRET>::m_bsgs.n);
87 sir.apply2(RBase<BSGSIN,TRANSRET>::m_partition2, empty);
88
89 RBase<BSGSIN,TRANSRET>::construct(stabPred, 0);
90 }
91
92 template<class BSGSIN,class TRANSRET>
processNewFixPoints(const Partition & pi,unsigned int level)93 unsigned int SetImageSearch<BSGSIN,TRANSRET>::processNewFixPoints(const Partition& pi, unsigned int level) {
94 const unsigned int basePos = RBase<BSGSIN,TRANSRET>::processNewFixPoints(pi, level);
95 if (!this->m_limitInitialized) {
96 bool allFound = true;
97 BOOST_FOREACH(unsigned long alpha, toStab) {
98 if (std::find(pi.fixPointsBegin(), pi.fixPointsEnd(), alpha) == pi.fixPointsEnd()) {
99 allFound = false;
100 break;
101 }
102 }
103 if (allFound) {
104 this->m_limitLevel = level;
105 this->m_limitBase = basePos;
106 this->m_limitInitialized = true;
107 }
108 }
109 return basePos;
110 }
111
112 }
113 }
114
115 #endif // -- PARTITION_SET_IMAGE_SEARCH_H_
116