permlib  0.2.6
Library for permutation computations
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include/permlib/predicate/matrix_automorphism_predicate.h
00001 // ---------------------------------------------------------------------------
00002 //
00003 //  This file is part of PermLib.
00004 //
00005 // Copyright (c) 2009-2011 Thomas Rehn <thomas@carmen76.de>
00006 // All rights reserved.
00007 // 
00008 // Redistribution and use in source and binary forms, with or without
00009 // modification, are permitted provided that the following conditions
00010 // are met:
00011 // 1. Redistributions of source code must retain the above copyright
00012 //    notice, this list of conditions and the following disclaimer.
00013 // 2. Redistributions in binary form must reproduce the above copyright
00014 //    notice, this list of conditions and the following disclaimer in the
00015 //    documentation and/or other materials provided with the distribution.
00016 // 3. The name of the author may not be used to endorse or promote products
00017 //    derived from this software without specific prior written permission.
00018 // 
00019 // THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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00029 //
00030 // ---------------------------------------------------------------------------
00031 
00032 
00033 #ifndef MATRIXAUTOMORPHISMPREDICATE_H_
00034 #define MATRIXAUTOMORPHISMPREDICATE_H_
00035 
00036 #include <permlib/predicate/subgroup_predicate.h>
00037 #include <permlib/search/partition/refinement_family.h>
00038 
00039 #include <boost/foreach.hpp>
00040 
00041 namespace permlib {
00042 
00044 template <class PERM,class MATRIX>
00045 class MatrixAutomorphismPredicate : public SubgroupPredicate<PERM> {
00046 public:
00048         MatrixAutomorphismPredicate(const MATRIX& matrix);
00049 
00050         virtual bool operator()(const PERM &p) const;
00051         virtual bool childRestriction(const PERM &h, unsigned int i, unsigned long beta_i) const;
00052         virtual unsigned int limit() const;
00053 private:
00054         const MATRIX& m_matrix;
00055 };
00056 
00057 //
00058 //     ----       IMPLEMENTATION
00059 //
00060 
00061 template <class PERM,class MATRIX>
00062 MatrixAutomorphismPredicate<PERM,MATRIX>::MatrixAutomorphismPredicate(const MATRIX& matrix) 
00063         : m_matrix(matrix)
00064 { }
00065 
00066 template <class PERM,class MATRIX>
00067 bool MatrixAutomorphismPredicate<PERM,MATRIX>::operator()(const PERM &p) const {
00068         const unsigned long n = m_matrix.dimension();
00069         for (unsigned long i = 0; i < n; ++i) {
00070                 for (unsigned long j = i; j < n; ++j) {
00071                         if (m_matrix.at(i, j) != m_matrix.at(p / i, p / j))
00072                                 return false;
00073                 }
00074         }
00075         return true;
00076 }
00077 
00078 template <class PERM,class MATRIX>
00079 bool MatrixAutomorphismPredicate<PERM,MATRIX>::childRestriction(const PERM &h, unsigned int i, unsigned long beta_i) const {
00080         // we can't easily restrict child nodes in general, so we don't restrict at all
00081         return true;
00082 }
00083 
00084 template <class PERM,class MATRIX>
00085 unsigned int MatrixAutomorphismPredicate<PERM,MATRIX>::limit() const {
00086         // we can't easily limit the search depth, so return maximal depth
00087         return m_matrix.dimension();
00088 }
00089 
00090 }
00091 
00092 #endif // -- MATRIXAUTOMORPHISMPREDICATE_H_