matrix_refinement1.h

// ---------------------------------------------------------------------------
//
//  This file is part of PermLib.
//
// Copyright (c) 2009-2011 Thomas Rehn <thomas@carmen76.de>
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// ---------------------------------------------------------------------------
 
 
#ifndef MATRIXREFINEMENT1_H_
#define MATRIXREFINEMENT1_H_
 
#include <permlib/predicate/pointwise_stabilizer_predicate.h>
#include <permlib/search/partition/refinement.h>
 
namespace permlib {
namespace partition {


template<class PERM,class MATRIX>
class MatrixRefinement1 : public Refinement<PERM> {
public:
        explicit MatrixRefinement1(unsigned long n, const MATRIX& matrix);
        
        virtual unsigned int apply(Partition& pi) const;
        
        virtual bool init(Partition& pi);
        
private:
        const MATRIX& m_matrix;
        std::vector<std::list<unsigned long> > m_diagonalPartition;
};
 
template<class PERM,class MATRIX>
MatrixRefinement1<PERM,MATRIX>::MatrixRefinement1(unsigned long n, const MATRIX& matrix) 
        : Refinement<PERM>(n, Default), m_matrix(matrix)
{
}
 
template<class PERM,class MATRIX>
unsigned int MatrixRefinement1<PERM,MATRIX>::apply(Partition& pi) const {
        BOOST_ASSERT( this->initialized() );
        
        unsigned int ret = 0;
        std::list<int>::const_iterator cellPairIt = Refinement<PERM>::m_cellPairs.begin();
        while (cellPairIt != Refinement<PERM>::m_cellPairs.end()) {
                unsigned long cell = *cellPairIt;
                ++cellPairIt;
                while (cellPairIt != Refinement<PERM>::m_cellPairs.end() && *cellPairIt != -1) {
                        unsigned long diagIndex = *cellPairIt;
                        if (pi.intersect(m_diagonalPartition[diagIndex].begin(), m_diagonalPartition[diagIndex].end(), cell))
                                ++ret;
                        ++cellPairIt;
                }
                ++cellPairIt;
        }
        return ret;
}
 
 
template<class PERM,class MATRIX>
bool MatrixRefinement1<PERM,MATRIX>::init(Partition& pi) {
        m_diagonalPartition.resize(m_matrix.k());
        for (unsigned long i = 0; i < m_matrix.dimension(); ++i) {
                m_diagonalPartition[m_matrix.at(i,i)].push_back(i);
        }
        
        bool foundIntersection = false;
        for (unsigned int c = 0; c < pi.cells(); ++c) {
                Refinement<PERM>::m_cellPairs.push_back(c);
                for (unsigned long i = 0; i < m_diagonalPartition.size(); ++i) {
                        if (pi.intersect(m_diagonalPartition[i].begin(), m_diagonalPartition[i].end(), c)) {
                                Refinement<PERM>::m_cellPairs.push_back(i);
                                foundIntersection = true;
                        }
                }
                Refinement<PERM>::m_cellPairs.push_back(-1);
        }
        if (foundIntersection) {
                typename Refinement<PERM>::RefinementPtr ref(new MatrixRefinement1<PERM,MATRIX>(*this));
                Refinement<PERM>::m_backtrackRefinements.push_back(ref);
                return true;
        }
        return false;
}
 
 
}
}
 
#endif // -- MATRIXREFINEMENT1_H_