permlib 0.2.9
Library for permutation computations
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matrix_automorphism_predicate.h
1// ---------------------------------------------------------------------------
2//
3// This file is part of PermLib.
4//
5// Copyright (c) 2009-2011 Thomas Rehn <thomas@carmen76.de>
6// All rights reserved.
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31
32
33#ifndef MATRIXAUTOMORPHISMPREDICATE_H_
34#define MATRIXAUTOMORPHISMPREDICATE_H_
35
36#include <permlib/predicate/subgroup_predicate.h>
37#include <permlib/search/partition/refinement_family.h>
38
39#include <boost/foreach.hpp>
40
41namespace permlib {
42
44template <class PERM,class MATRIX>
46public:
48 MatrixAutomorphismPredicate(const MATRIX& matrix);
49
50 virtual bool operator()(const PERM &p) const;
51 virtual bool childRestriction(const PERM &h, unsigned int i, unsigned long beta_i) const;
52 virtual unsigned int limit() const;
53private:
54 const MATRIX& m_matrix;
55};
56
57//
58// ---- IMPLEMENTATION
59//
60
61template <class PERM,class MATRIX>
63 : m_matrix(matrix)
64{ }
65
66template <class PERM,class MATRIX>
68 const unsigned long n = m_matrix.dimension();
69 for (unsigned long i = 0; i < n; ++i) {
70 for (unsigned long j = i; j < n; ++j) {
71 if (m_matrix.at(i, j) != m_matrix.at(p / i, p / j))
72 return false;
73 }
74 }
75 return true;
76}
77
78template <class PERM,class MATRIX>
79bool MatrixAutomorphismPredicate<PERM,MATRIX>::childRestriction(const PERM &h, unsigned int i, unsigned long beta_i) const {
80 // we can't easily restrict child nodes in general, so we don't restrict at all
81 return true;
82}
83
84template <class PERM,class MATRIX>
86 // we can't easily limit the search depth, so return maximal depth
87 return m_matrix.dimension();
88}
89
90}
91
92#endif // -- MATRIXAUTOMORPHISMPREDICATE_H_
virtual bool childRestriction(const PERM &h, unsigned int i, unsigned long beta_i) const
checks if a given group element should not be followed in backtrack search
Definition matrix_automorphism_predicate.h:79
virtual unsigned int limit() const
limit of recursion depth in backtrack search
Definition matrix_automorphism_predicate.h:85
virtual bool operator()(const PERM &p) const
true iff group element fulfills predicate
Definition matrix_automorphism_predicate.h:67
MatrixAutomorphismPredicate(const MATRIX &matrix)
constructor
Definition matrix_automorphism_predicate.h:62
abstract base class for subgroup (and coset) predicates
Definition subgroup_predicate.h:45