dag.h

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/*  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_dag_h
#define __defined_libdai_dag_h


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


namespace dai {



class DAG {
    private:
        std::vector<Neighbors> _pa;
        
        std::vector<Neighbors> _ch;

    public:

        DAG() : _pa(), _ch() {}

        DAG( size_t nr ) : _pa( nr ), _ch( nr ) {}


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


        const Neighbor& pa( size_t n, size_t _p ) const {
            DAI_DEBASSERT( n < _pa.size() );
            DAI_DEBASSERT( _p < _pa[n].size() );
            return _pa[n][_p];
        }
        Neighbor& pa( size_t n, size_t _p ) {
            DAI_DEBASSERT( n < _pa.size() );
            DAI_DEBASSERT( _p < _pa[n].size() );
            return _pa[n][_p];
        }

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

        const Neighbor& ch( size_t n, size_t _c ) const {
            DAI_DEBASSERT( n < _ch.size() );
            DAI_DEBASSERT( _c < _ch[n].size() );
            return _ch[n][_c];
        }
        Neighbor& ch( size_t n, size_t _c ) {
            DAI_DEBASSERT( n < _ch.size() );
            DAI_DEBASSERT( _c < _ch[n].size() );
            return _ch[n][_c];
        }

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



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

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


        template <typename NodeInputIterator>
        size_t addNode( NodeInputIterator begin, NodeInputIterator end, size_t sizeHint=0 ) {
            Neighbors newparents;
            newparents.reserve( sizeHint );
            size_t iter = 0;
            for( NodeInputIterator it = begin; it != end; ++it ) {
                DAI_ASSERT( *it < nrNodes() );
                Neighbor newparent( iter, *it, ch(*it).size() );
                Neighbor newchild( ch(*it).size(), nrNodes(), iter++ );
                newparents.push_back( newparent );
                ch( *it ).push_back( newchild );
            }
            _pa.push_back( newparents );
            _ch.push_back( Neighbors() );
            return _pa.size() - 1;
        }


        DAG& 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 {
            DAI_DEBASSERT( _pa.size() == _ch.size() );
            return _pa.size();
        }

        size_t nrEdges() const {
            size_t sum = 0;
            for( size_t i = 0; i < _pa.size(); i++ )
                sum += _pa[i].size();
            return sum;
        }


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


        size_t findPa( size_t n, size_t p ) {
            for( size_t _p = 0; _p < pa(n).size(); _p++ )
                if( pa( n, _p ) == p )
                    return _p;
            DAI_THROW(OBJECT_NOT_FOUND);
            return pa(n).size();
        }


        size_t findCh( size_t n, size_t c ) {
            for( size_t _c = 0; _c < ch(n).size(); _c++ )
                if( ch( n, _c ) == c )
                    return _c;
            DAI_THROW(OBJECT_NOT_FOUND);
            return ch(n).size();
        }

        SmallSet<size_t> paSet( size_t n ) const;

        SmallSet<size_t> chSet( size_t n ) const;

        std::set<size_t> ancestors( size_t n, bool inclusive ) const;

        std::set<size_t> descendants( size_t n, bool inclusive ) const;

        bool existsDirectedPath( size_t n1, size_t n2 ) const;

        bool isConnected() const;

        void checkConsistency() const;


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


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

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

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


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

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


} // end of namespace dai


#endif