permlib  0.2.9
Library for permutation computations
matrix_automorphism_predicate.h
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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 
41 namespace permlib {
42 
44 template <class PERM,class MATRIX>
46 public:
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;
53 private:
54  const MATRIX& m_matrix;
55 };
56 
57 //
58 // ---- IMPLEMENTATION
59 //
60 
61 template <class PERM,class MATRIX>
63  : m_matrix(matrix)
64 { }
65 
66 template <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 
78 template <class PERM,class MATRIX>
79 bool 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 
84 template <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 operator()(const PERM &p) const
true iff group element fulfills predicate
Definition: matrix_automorphism_predicate.h:67
predicate for the automorphisms of a symmetric matrix
Definition: matrix_automorphism_predicate.h:45
virtual unsigned int limit() const
limit of recursion depth in backtrack search
Definition: matrix_automorphism_predicate.h:85
MatrixAutomorphismPredicate(const MATRIX &matrix)
constructor
Definition: matrix_automorphism_predicate.h:62
abstract base class for subgroup (and coset) predicates
Definition: subgroup_predicate.h:45
Definition: abstract_bsgs.h:49
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