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2 //
3 //  This file is part of PermLib.
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5 // Copyright (c) 2009-2012 Thomas Rehn <thomas@carmen76.de>
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31 
32 #include <vector>
33 #include <list>
34 #include <set>
35 
36 #include <boost/cstdint.hpp>
37 #include <boost/foreach.hpp>
38 #include <boost/dynamic_bitset.hpp>
39 
40 #include <permlib/common.h>
41 
42 #ifndef ABSTRACT_PERMUTATION_GROUP_H_
43 #define ABSTRACT_PERMUTATION_GROUP_H_
44 
45 namespace permlib {
46 
47 /// implementation type for abstract class AbstractPermutationGroup
48 enum AbstractGroupType {
49 	AGT_BSGS = 1,
50 	AGT_SymmetricProduct = 2
51 };
52 
53 /// A high level interface for a permutation group
54 class AbstractPermutationGroup {
55 public:
56 	/// destructor
~AbstractPermutationGroup()57 	virtual ~AbstractPermutationGroup() {}
58 
59 	/// order of the group
60 	template<typename Integer>
61 	Integer order() const;
62 
63 	/// order of the group
64 	boost::uint64_t order() const;
65 
66 	/// computes the stabilizer of a set
67 	/**
68 	 * @param s set to be stabilized
69 	 * @return stabilizer; may return <i>this</i> if set is already stabilized
70 	 */
71 	virtual AbstractPermutationGroup* setStabilizer(const std::vector<dom_int>& s) const = 0;
72 
73 	/// typedef for a list of orbits, each of which is a set
74 	typedef std::list<std::set<dom_int> > OrbitList;
75 	/// computes all orbits
76 	virtual OrbitList* orbits() const = 0;
77 	/// computes all orbits which contain a given set of elements
78 	/**
79 	 * @param s set of elements of which orbit has to be computed; vector must be sorted
80 	 * @return all orbits of the group which contain an elements from s
81 	 */
82 	virtual OrbitList* orbits(const std::vector<dom_int>& s) const = 0;
83 
84 	/// checks whether a set is lexicographically minimal with respect to a given ordering of indices
85 	/**
86 	 * @param setIndices indices of the set for which minimality has to checked
87 	 * @param rankIndices list of indices; the order of these indices defines a partial order on {1..n}
88 	 * @return true iff set is minimal with respect to given ordering
89 	 */
90 	virtual bool isLexMinSet(const std::vector<dom_int>& setIndices, const std::vector<dom_int>& rankIndices) const = 0;
91 
92 	/// implementation type of this abstract class
93 	virtual AbstractGroupType type() const = 0;
94 protected:
95 	/// fills a list with sizes of transversals along a stabilizer chain
96 	virtual void transversalSizes(std::vector<unsigned long>& sizes) const = 0;
97 };
98 
99 
100 template <typename Integer>
order()101 Integer AbstractPermutationGroup::order() const {
102 	Integer orderValue(1);
103 	std::vector<unsigned long> sizes;
104 	transversalSizes(sizes);
105 	BOOST_FOREACH(const unsigned long &s, sizes) {
106 		orderValue *= s;
107 	}
108 	return orderValue;
109 }
110 
order()111 inline boost::uint64_t AbstractPermutationGroup::order() const {
112 	return order<boost::uint64_t>();
113 }
114 
115 } // end NS
116 
117 #endif
118