graph.h

Go to the documentation of this file.

/*  This file is part of libDAI - http://www.libdai.org/
 *
 *  Copyright (c) 2006-2011, The libDAI authors. All rights reserved.
 *
 *  Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
 */




#ifndef __defined_libdai_graph_h
#define __defined_libdai_graph_h


#include <ostream>
#include <vector>
#include <algorithm>
#include <dai/util.h>
#include <dai/exceptions.h>
#include <dai/smallset.h>


namespace dai {



struct Neighbor {
    size_t iter;
    size_t node;
    size_t dual;

    Neighbor() {}
    Neighbor( size_t iter, size_t node, size_t dual ) : iter(iter), node(node), dual(dual) {}

    operator size_t () const { return node; }
};


typedef std::vector<Neighbor> Neighbors;



typedef std::pair<size_t,size_t> Edge;



class GraphAL {
    private:
        std::vector<Neighbors> _nb;

    public:

        GraphAL() : _nb() {}

        GraphAL( size_t nr ) : _nb( nr ) {}


        template<typename EdgeInputIterator>
        GraphAL( size_t nr, EdgeInputIterator begin, EdgeInputIterator end, bool check=true ) : _nb() {
            construct( nr, begin, end, check );
        }


        const Neighbor & nb( size_t n1, size_t _n2 ) const {
            DAI_DEBASSERT( n1 < _nb.size() );
            DAI_DEBASSERT( _n2 < _nb[n1].size() );
            return _nb[n1][_n2];
        }
        Neighbor & nb( size_t n1, size_t _n2 ) {
            DAI_DEBASSERT( n1 < _nb.size() );
            DAI_DEBASSERT( _n2 < _nb[n1].size() );
            return _nb[n1][_n2];
        }

        const Neighbors & nb( size_t n ) const {
            DAI_DEBASSERT( n < _nb.size() );
            return _nb[n];
        }
        Neighbors & nb( size_t n ) {
            DAI_DEBASSERT( n < _nb.size() );
            return _nb[n];
        }



        template<typename EdgeInputIterator>
        void construct( size_t nr, EdgeInputIterator begin, EdgeInputIterator end, bool check=true );

        size_t addNode() { _nb.push_back( Neighbors() ); return _nb.size() - 1; }


        template <typename NodeInputIterator>
        size_t addNode( NodeInputIterator begin, NodeInputIterator end, size_t sizeHint = 0 ) {
            Neighbors nbsnew;
            nbsnew.reserve( sizeHint );
            size_t iter = 0;
            for( NodeInputIterator it = begin; it != end; ++it ) {
                DAI_ASSERT( *it < nrNodes() );
                Neighbor nb1new( iter, *it, nb(*it).size() );
                Neighbor nb2new( nb(*it).size(), nrNodes(), iter++ );
                nbsnew.push_back( nb1new );
                nb( *it ).push_back( nb2new );
            }
            _nb.push_back( nbsnew );
            return _nb.size() - 1;
        }


        GraphAL& addEdge( size_t n1, size_t n2, bool check = true );


        void eraseNode( size_t n );

        void eraseEdge( size_t n1, size_t n2 );


        size_t nrNodes() const { return _nb.size(); }

        size_t nrEdges() const {
            size_t sum = 0;
            for( size_t i = 0; i < nrNodes(); i++ )
                sum += nb(i).size();
            return sum / 2;
        }


        bool hasEdge( size_t n1, size_t n2 ) const {
            if( nb(n1).size() < nb(n2).size() ) {
                for( size_t _n2 = 0; _n2 < nb(n1).size(); _n2++ )
                    if( nb( n1, _n2 ) == n2 )
                        return true;
            } else {
                for( size_t _n1 = 0; _n1 < nb(n2).size(); _n1++ )
                    if( nb( n2, _n1 ) == n1 )
                        return true;
            }
            return false;
        }


        size_t findNb( size_t n1, size_t n2 ) {
            for( size_t _n2 = 0; _n2 < nb(n1).size(); _n2++ )
                if( nb( n1, _n2 ) == n2 )
                    return _n2;
            DAI_THROW(OBJECT_NOT_FOUND);
            return nb(n1).size();
        }

        SmallSet<size_t> nbSet( size_t n ) const;

        bool isConnected() const;

        bool isTree() const;

        void checkConsistency() const;


        bool operator==( const GraphAL& x ) const {
            if( nrNodes() != x.nrNodes() )
                return false;
            for( size_t n1 = 0; n1 < nrNodes(); n1++ ) {
                if( nb(n1).size() != x.nb(n1).size() )
                    return false;
                bforeach( const Neighbor &n2, nb(n1) )
                    if( !x.hasEdge( n1, n2 ) )
                        return false;
                bforeach( const Neighbor &n2, x.nb(n1) )
                    if( !hasEdge( n1, n2 ) )
                        return false;
            }
            return true;
        }


        void printDot( std::ostream& os ) const;

        friend std::ostream& operator<<( std::ostream& os, const GraphAL& g ) {
            g.printDot( os );
            return os;
        }

        std::string toString() const {
            std::stringstream ss;
            ss << *this;
            return ss.str();
        }
};


template<typename EdgeInputIterator>
void GraphAL::construct( size_t nr, EdgeInputIterator begin, EdgeInputIterator end, bool check ) {
    _nb.clear();
    _nb.resize( nr );

    for( EdgeInputIterator e = begin; e != end; e++ )
        addEdge( e->first, e->second, check );
}


GraphAL createGraphFull( size_t N );
GraphAL createGraphGrid( size_t N1, size_t N2, bool periodic );
GraphAL createGraphGrid3D( size_t N1, size_t N2, size_t N3, bool periodic );
GraphAL createGraphLoop( size_t N );
GraphAL createGraphTree( size_t N );

GraphAL createGraphRegular( size_t N, size_t d );


} // end of namespace dai


#endif