permlib  0.2.9
Library for permutation computations
set_image_predicate.h
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31 
32 
33 #ifndef SETIMAGEPREDICATE_H_
34 #define SETIMAGEPREDICATE_H_
35 
36 #include <permlib/predicate/subgroup_predicate.h>
37 
38 #include <boost/foreach.hpp>
39 
40 namespace permlib {
41 
43 
46 template <class PERM>
47 class SetImagePredicate : public SubgroupPredicate<PERM> {
48 public:
50 
56  template<class InputIterator>
57  SetImagePredicate(InputIterator deltaBegin, InputIterator deltaEnd, InputIterator gammaBegin, InputIterator gammaEnd);
58 
59  virtual bool operator()(const PERM &p) const;
60  virtual bool childRestriction(const PERM &h, unsigned int i, unsigned long beta_i) const;
61  virtual unsigned int limit() const;
62 private:
63  //TODO: perhaps use std::set here?
64  std::vector<unsigned long> m_delta;
65  std::vector<unsigned long> m_gamma;
66 };
67 
68 //
69 // ---- IMPLEMENTATION
70 //
71 
72 template <class PERM>
73 template<class InputIterator>
74 SetImagePredicate<PERM>::SetImagePredicate(InputIterator deltaBegin, InputIterator deltaEnd, InputIterator gammaBegin, InputIterator gammaEnd)
75  : m_delta(deltaBegin, deltaEnd), m_gamma(gammaBegin, gammaEnd)
76 {
77  BOOST_ASSERT(m_delta.size() == m_gamma.size());
78 }
79 
80 
81 template <class PERM>
82 bool SetImagePredicate<PERM>::operator()(const PERM &p) const {
83  BOOST_FOREACH(unsigned long delta_i, m_delta) {
84  if (std::find(m_gamma.begin(), m_gamma.end(), p / delta_i) == m_gamma.end())
85  return false;
86  }
87  return true;
88 }
89 
90 template <class PERM>
91 bool SetImagePredicate<PERM>::childRestriction(const PERM &h, unsigned int i, unsigned long beta_i) const {
92  if (std::find(m_gamma.begin(), m_gamma.end(), h / beta_i) == m_gamma.end())
93  return false;
94  return true;
95 }
96 
97 template <class PERM>
98 unsigned int SetImagePredicate<PERM>::limit() const {
99  return m_delta.size();
100 }
101 
102 }
103 
104 #endif // -- SETIMAGEPREDICATE_H_
virtual bool operator()(const PERM &p) const
true iff group element fulfills predicate
Definition: set_image_predicate.h:82
SetImagePredicate(InputIterator deltaBegin, InputIterator deltaEnd, InputIterator gammaBegin, InputIterator gammaEnd)
constructor
Definition: set_image_predicate.h:74
coset-type predicate for group elements that map one set of points onto another given set of points ...
Definition: set_image_predicate.h:47
virtual unsigned int limit() const
limit of recursion depth in backtrack search
Definition: set_image_predicate.h:98
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: set_image_predicate.h:91
abstract base class for subgroup (and coset) predicates
Definition: subgroup_predicate.h:45
Definition: abstract_bsgs.h:49