// ==========================================================================
//                 SeqAn - The Library for Sequence Analysis
// ==========================================================================
// Copyright (c) 2006-2016, Knut Reinert, FU Berlin
// All rights reserved.
//
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// modification, are permitted provided that the following conditions are met:
//
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//       notice, this list of conditions and the following disclaimer in the
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//       its contributors may be used to endorse or promote products derived
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#ifndef SEQAN_HEADER_GRAPH_IMPL_UNDIRECTED_H
#define SEQAN_HEADER_GRAPH_IMPL_UNDIRECTED_H

namespace seqan
{
//////////////////////////////////////////////////////////////////////////////
// Graph - Undirected
//////////////////////////////////////////////////////////////////////////////

//////////////////////////////////////////////////////////////////////////////

/*!
 * @class UndirectedGraph
 * @extends Graph
 * @headerfile <seqan/graph_types.h>
 * @brief An undirected graph that stores the edges in an adjacency list.
 *
 * <img src="undirectedGraph.png" title="An undirected graph with multiple components." />
 *
 * @signature template <[typename TCargo[, typename Spec]]>
 *            class Graph<Undirected<TCargo, TSpec> >;
 *
 * @tparam TCargo The cargo type that can be attached to the edges.  Default: <tt>void</tt>.
 * @tparam TSpec  The specializing type.  Default: <tt>Default</tt>.  NB: if edges do not store ids then external
 *                property maps do not work.
 */

template<typename TCargo,typename TSpec>
class Graph<Undirected<TCargo, TSpec> >
{
    public:
        typedef typename VertexIdHandler<Graph>::Type TVertexIdManager_;
        typedef typename EdgeIdHandler<Graph>::Type TEdgeIdManager_;
        typedef typename EdgeType<Graph>::Type TEdgeStump_;
        typedef Allocator<SinglePool<sizeof(TEdgeStump_)> > TAllocator_;

        String<TEdgeStump_*> data_vertex;            // Pointers to EdgeStump lists
        TVertexIdManager_ data_id_managerV;
        TEdgeIdManager_ data_id_managerE;
        TAllocator_ data_allocator;

//____________________________________________________________________________


        Graph() {
        }


        ~Graph() {
            clear(*this);
        }

        Graph(Graph const & _other) :
            data_allocator(_other.data_allocator)
        {
            _copyGraph(_other, *this);
        }

        Graph const& operator = (Graph const & _other) {
            if (this == &_other) return *this;
            clear(*this);
            data_allocator = _other.data_allocator;
            _copyGraph(_other, *this);
            return *this;
        }
};

//////////////////////////////////////////////////////////////////////////////
// INTERNAL FUNCTIONS
//////////////////////////////////////////////////////////////////////////////

//////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TSpec>
inline String<typename EdgeType<Graph<Undirected<TCargo, TSpec> > >::Type*>&
_getVertexString(Graph<Undirected<TCargo, TSpec> > const& g) {
    typedef Graph<Undirected<TCargo, TSpec> > TGraph;
    typedef typename EdgeType<TGraph>::Type TEdgeStump;
    return const_cast<String<TEdgeStump*>&>(g.data_vertex);
}

/////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TSpec>
inline typename VertexIdHandler<Graph<Undirected<TCargo, TSpec> > >::Type&
_getVertexIdManager(Graph<Undirected<TCargo, TSpec> > const& g) {
    typedef Graph<Undirected<TCargo, TSpec> > TGraph;
    typedef typename VertexIdHandler<TGraph>::Type TVertexIdManager;
    return const_cast<TVertexIdManager&>(g.data_id_managerV);
}

//////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TSpec>
inline typename EdgeIdHandler<Graph<Undirected<TCargo, TSpec> > >::Type&
_getEdgeIdManager(Graph<Undirected<TCargo, TSpec> > const& g) {
    typedef Graph<Undirected<TCargo, TSpec> > TGraph;
    typedef typename EdgeIdHandler<TGraph>::Type TEdgeIdManager;
    return const_cast<TEdgeIdManager&>(g.data_id_managerE);
}

//////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TSpec>
inline void
_copyGraph(Graph<Undirected<TCargo, TSpec> > const& source,
           Graph<Undirected<TCargo, TSpec> >& dest,
           bool)
{
    typedef Graph<Undirected<TCargo, TSpec> > TGraph;
    typedef typename VertexDescriptor<TGraph>::Type TVertexDescriptor;
    typedef typename EdgeDescriptor<TGraph>::Type TEdgeDescriptor;
    typedef typename EdgeType<TGraph>::Type TEdgeStump;
    typedef typename Iterator<String<TEdgeStump*> const, Standard>::Type TIterConst;
    typedef typename Iterator<String<TEdgeStump*>, Standard>::Type TIter;
    clear(dest);
    resize(dest.data_vertex, length(_getVertexString(source)));
    TIter itInit = begin(dest.data_vertex, Standard());
    TIter itInitEnd = end(dest.data_vertex, Standard());
    for(;itInit!=itInitEnd; ++itInit) *itInit = (TEdgeStump*) 0;
    TIterConst it = begin(source.data_vertex, Standard());
    TIterConst itEnd = end(source.data_vertex, Standard());
    TVertexDescriptor pos = 0;
    for(;it!=itEnd;++it, ++pos) {
        TEdgeStump* current = *it;
        TVertexDescriptor sourceVertex = pos;
        while(current != (TEdgeStump*) 0) {
            TVertexDescriptor targetVertex = getTarget(current);

            if (targetVertex != sourceVertex) {
                // Create missing vertices, targetVertex is always bigger than sourceVertex
                _createVertices(dest,targetVertex);

                // Add edge
                TEdgeDescriptor e = addEdge(dest, sourceVertex, targetVertex);
                _assignId(e, _getId(current));
                assignCargo(e, getCargo(current));
                current = getNextS(current);  // Follow the link belonging to the source id
            } else {
                // Do nothing here because we don't want to create edges twice!!!
                current = getNextT(current);
            }
        }
    }
    dest.data_id_managerV = source.data_id_managerV;
    dest.data_id_managerE = source.data_id_managerE;
}


template<typename TCargo, typename TSpec>
inline void
_copyGraph(Graph<Undirected<TCargo, TSpec> > const& source,
           Graph<Undirected<TCargo, TSpec> >& dest)
{
    _copyGraph(source, dest, false); // Never transpose because undirected and transposed undirected graph are equal
}

//////////////////////////////////////////////////////////////////////////////
// FUNCTIONS
//////////////////////////////////////////////////////////////////////////////

//////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TSpec>
inline void
transpose(Graph<Undirected<TCargo, TSpec> > const& source,
          Graph<Undirected<TCargo, TSpec> >& dest)
{
    // Undirected graph, no transpose just copy
    _copyGraph(source, dest, false);

}

//////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TSpec>
inline void
transpose(Graph<Undirected<TCargo, TSpec> > const&)
{
    // Nothing to do
}

//////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TSpec>
inline typename Size<Graph<Undirected<TCargo, TSpec> > >::Type
numEdges(Graph<Undirected<TCargo, TSpec> > const& g)
{
    return idCount(g.data_id_managerE);
}

//////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TSpec>
inline typename Size<Graph<Undirected<TCargo, TSpec> > >::Type
numVertices(Graph<Undirected<TCargo, TSpec> > const& g)
{
    return idCount(g.data_id_managerV);
}

//////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TSpec>
inline bool
empty(Graph<Undirected<TCargo, TSpec> > const& g)
{
    return (!(idCount(g.data_id_managerV)));
}

//////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TSpec>
inline void
clearEdges(Graph<Undirected<TCargo, TSpec> >& g)
{
    typedef Graph<Undirected<TCargo, TSpec> > TGraph;
    typedef typename VertexDescriptor<TGraph>::Type TVertexDescriptor;
    typedef typename EdgeDescriptor<TGraph>::Type TEdgeDescriptor;
    typedef typename EdgeType<TGraph>::Type TEdgeStump;
    typedef typename Iterator<String<TEdgeStump*>, Standard>::Type TIter;

    // Collect all edges
    String<TEdgeDescriptor> edges;
    TIter it = begin(g.data_vertex, Standard());
    TIter itEnd = end(g.data_vertex, Standard());
    TVertexDescriptor pos = 0;
    for(;it!=itEnd; ++it, ++pos) {
        TEdgeStump* current = *it;
        TVertexDescriptor sourceVertex = pos;
        while(current != (TEdgeStump*) 0) {
            if (getTarget(current) != sourceVertex) {
                appendValue(edges, current, Generous());
                current = getNextS(current);
            }
            // Do nothing here because we don't want to create edges twice!!!
            else current = getNextT(current);
        }
        *it = (TEdgeStump*) 0;
    }
    SEQAN_ASSERT(numEdges(g) == length(edges));

    // Release all edges
    typedef typename Iterator<String<TEdgeDescriptor>, Standard>::Type TStringIter;
    TStringIter edgeIt = begin(edges, Standard());
    TStringIter edgeEndIt = end(edges, Standard());
    for(; edgeIt != edgeEndIt; ++edgeIt) {
        valueDestruct(*edgeIt);
        deallocate(g.data_allocator, *edgeIt, 1);
    }
    releaseAll(g.data_id_managerE);
}

//////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TSpec>
inline void
clearVertices(Graph<Undirected<TCargo, TSpec> >& g)
{
    clearEdges(g);
    releaseAll(g.data_id_managerV);
    clear(g.data_vertex);
}

//////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TSpec>
inline void
clear(Graph<Undirected<TCargo, TSpec> >& g)
{
    clearVertices(g);
}

//////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TSpec, typename TVertexDescriptor>
inline typename Size<Graph<Undirected<TCargo, TSpec> > >::Type
outDegree(Graph<Undirected<TCargo, TSpec> > const& g,
          TVertexDescriptor const vertex)
{
    SEQAN_ASSERT(idInUse(g.data_id_managerV, vertex));

    typedef Graph<Undirected<TCargo, TSpec> > TGraph;
    typedef typename EdgeType<TGraph>::Type TEdgeStump;
    typedef typename Size<TGraph>::Type TSize;
    TSize count=0;
    TEdgeStump* current = g.data_vertex[vertex];
    while(current!=0) {
        if ( (TVertexDescriptor) getTarget(current)==vertex) current = getNextT(current);
        else current = getNextS(current);
        ++count;
    }
    return count;
}

//////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TSpec, typename TVertexDescriptor>
inline typename Size<Graph<Undirected<TCargo, TSpec> > >::Type
inDegree(Graph<Undirected<TCargo, TSpec> > const& g,
         TVertexDescriptor const vertex)
{
    // In-degree and out-degree are equal for undirected graphs
    return outDegree(g,vertex);
}

//////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TSpec, typename TVertexDescriptor>
inline typename Size<Graph<Undirected<TCargo, TSpec> > >::Type
degree(Graph<Undirected<TCargo, TSpec> > const& g,
       TVertexDescriptor const vertex)
{
    return outDegree(g,vertex);
}

//////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TSpec>
inline typename VertexDescriptor<Graph<Undirected<TCargo, TSpec> > >::Type
addVertex(Graph<Undirected<TCargo, TSpec> >& g)
{
    typedef Graph<Undirected<TCargo, TSpec> > TGraph;
    typedef typename VertexDescriptor<TGraph>::Type TVertexDescriptor;
    typedef typename EdgeType<TGraph>::Type TEdgeStump;
    TVertexDescriptor vd = obtainId(g.data_id_managerV);
    if (vd == length(g.data_vertex)) appendValue(g.data_vertex, (TEdgeStump*) 0, Generous());
    else g.data_vertex[vd] = (TEdgeStump*) 0;
    return vd;
}

//////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TSpec, typename TVertexDescriptor>
inline void
removeVertex(Graph<Undirected<TCargo, TSpec> >& g,
             TVertexDescriptor const v)
{
    SEQAN_ASSERT(idInUse(g.data_id_managerV, v));

    removeOutEdges(g,v); // Remove all outgoing edges
    releaseId(g.data_id_managerV, v); // Release id
}

//////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TSpec, typename TVertexDescriptor>
inline typename EdgeDescriptor<Graph<Undirected<TCargo, TSpec> > >::Type
addEdge(Graph<Undirected<TCargo, TSpec> >& g,
        TVertexDescriptor source,
        TVertexDescriptor target)
{
    SEQAN_ASSERT_NEQ(source, target);
    SEQAN_ASSERT(idInUse(g.data_id_managerV, source));
    SEQAN_ASSERT(idInUse(g.data_id_managerV, target));

    typedef Graph<Undirected<TCargo, TSpec> > TGraph;
    typedef typename EdgeType<TGraph>::Type TEdgeStump;
    typedef typename Id<TGraph>::Type TId;

    // Source must be the smaller vertex id
    if (source > target) {TVertexDescriptor tmp = target; target = source; source = tmp; }

    TEdgeStump* edge_ptr;
    allocate(g.data_allocator, edge_ptr, 1);
    valueConstruct(edge_ptr);
    assignSource(edge_ptr, source);
    assignTarget(edge_ptr, target);
    assignNextS(edge_ptr, (TEdgeStump*) 0);
    assignNextT(edge_ptr, (TEdgeStump*) 0);
    TId id = obtainId(g.data_id_managerE);
    _assignId(edge_ptr, id);
    if (g.data_vertex[source]!=0) assignNextS(edge_ptr, g.data_vertex[source]);
    if (g.data_vertex[target]!=0) assignNextT(edge_ptr, g.data_vertex[target]);
    g.data_vertex[source]=edge_ptr;
    g.data_vertex[target]=edge_ptr;
    return edge_ptr;
}

//////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TSpec, typename TVertexDescriptor, typename TCargo2>
inline typename EdgeDescriptor<Graph<Undirected<TCargo, TSpec> > >::Type
addEdge(Graph<Undirected<TCargo, TSpec> >& g,
        TVertexDescriptor const source,
        TVertexDescriptor const target,
        TCargo2 const cargo)
{
    SEQAN_ASSERT_NEQ(source, target);

    typedef Graph<Undirected<TCargo, TSpec> > TGraph;
    typedef typename EdgeDescriptor<TGraph>::Type TEdgeDescriptor;
    TEdgeDescriptor e = addEdge(g,source,target);
    assignCargo(e,cargo);
    return e;
}

//////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TSpec, typename TVertexDescriptor>
inline void
removeEdge(Graph<Undirected<TCargo, TSpec> >& g,
           TVertexDescriptor const source,
           TVertexDescriptor const target)
{
    SEQAN_ASSERT(idInUse(g.data_id_managerV, source));
    SEQAN_ASSERT(idInUse(g.data_id_managerV, target));

    typedef Graph<Undirected<TCargo, TSpec> > TGraph;
    typedef typename EdgeType<TGraph>::Type TEdgeStump;

    // Find edge and source predecessor
    TEdgeStump* predSource = 0;
    TEdgeStump* current = g.data_vertex[source];
    while(current != (TEdgeStump*) 0) {
        TVertexDescriptor adjV = (TVertexDescriptor) getTarget(current);
        if (adjV != source) {
            if ( adjV == target) break;
            predSource = current;
            current = getNextS(current);
        } else {
            adjV = (TVertexDescriptor) getSource(current);
            if ( adjV == target) break;
            predSource = current;
            current = getNextT(current);
        }
    }

    // Not found?
    if (current == (TEdgeStump*) 0) return;

    // Find edge and target predecessor
    TEdgeStump* predTarget = 0;
    current = g.data_vertex[target];
    while(current != (TEdgeStump*) 0) {
        TVertexDescriptor adjV = (TVertexDescriptor) getTarget(current);
        if (adjV != target) {
            if ( adjV == source) break;
            predTarget = current;
            current = getNextS(current);
        } else {
            adjV = (TVertexDescriptor) getSource(current);
            if ( adjV == source) break;
            predTarget = current;
            current = getNextT(current);
        }
    }


    // Relink the next pointer of source predecessor
    if (predSource != (TEdgeStump*) 0) {
        if (source != (TVertexDescriptor) getTarget(current)) {
            if (source != (TVertexDescriptor) getTarget(predSource)) assignNextS(predSource, getNextS(current));
            else assignNextT(predSource, getNextS(current));
        } else {
            if (source != (TVertexDescriptor) getTarget(predSource)) assignNextS(predSource, getNextT(current));
            else assignNextT(predSource, getNextT(current));
        }
    }
    else {
        if (source != (TVertexDescriptor) getTarget(current)) value(g.data_vertex, source) = getNextS(current);
        else value(g.data_vertex, source) = getNextT(current);
    }

    // Relink the next pointer of target predecessor
    if (predTarget != (TEdgeStump*) 0) {
        if (target != (TVertexDescriptor) getTarget(current)) {
            if (target != (TVertexDescriptor) getTarget(predTarget)) assignNextS(predTarget, getNextS(current));
            else assignNextT(predTarget, getNextS(current));
        } else {
            if (target != (TVertexDescriptor) getTarget(predTarget)) assignNextS(predTarget, getNextT(current));
            else assignNextT(predTarget, getNextT(current));
        }
    }
    else {
        if (target != (TVertexDescriptor) getTarget(current)) value(g.data_vertex, target) = getNextS(current);
        else value(g.data_vertex, target) = getNextT(current);
    }

    // Deallocate
    releaseId(g.data_id_managerE, _getId(current));
    valueDestruct(current);
    deallocate(g.data_allocator, current, 1);
}

//////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TSpec, typename TEdgeDescriptor>
inline void
removeEdge(Graph<Undirected<TCargo, TSpec> >& g,
           TEdgeDescriptor const edge)
{

    SEQAN_ASSERT(idInUse(g.data_id_managerV, sourceVertex(g,edge)));
    SEQAN_ASSERT(idInUse(g.data_id_managerV, targetVertex(g,edge)));
    typedef Graph<Undirected<TCargo, TSpec> > TGraph;
    typedef typename EdgeType<TGraph>::Type TEdgeStump;
    typedef typename VertexDescriptor<TGraph>::Type TVertexDescriptor;
    TVertexDescriptor source = sourceVertex(g,edge);
    TVertexDescriptor target = targetVertex(g,edge);

    // Find edge and source predecessor
    TEdgeStump* predSource = 0;
    TEdgeStump* current = g.data_vertex[source];
    while(current != (TEdgeStump*) 0) {
        TVertexDescriptor adjV = (TVertexDescriptor) getTarget(current);
        if (adjV != source) {
            if ((adjV == target) && (current == edge)) break;
            predSource = current;
            current = getNextS(current);
        } else {
            adjV = (TVertexDescriptor) getSource(current);
            if ((adjV == target) && (current == edge)) break;
            predSource = current;
            current = getNextT(current);
        }
    }

    // Not found?
    if (current == (TEdgeStump*) 0) return;

    // Find edge and target predecessor
    TEdgeStump* predTarget = 0;
    current = g.data_vertex[target];
    while(current != (TEdgeStump*) 0) {
        TVertexDescriptor adjV = (TVertexDescriptor) getTarget(current);
        if (adjV != target) {
            if ((adjV == source) && (current == edge)) break;
            predTarget = current;
            current = getNextS(current);
        } else {
            adjV = (TVertexDescriptor) getSource(current);
            if ((adjV == source) && (current == edge)) break;
            predTarget = current;
            current = getNextT(current);
        }
    }


    // Relink the next pointer of source predecessor
    if (predSource != (TEdgeStump*) 0) {
        if (source != (TVertexDescriptor) getTarget(current)) {
            if (source != (TVertexDescriptor) getTarget(predSource)) assignNextS(predSource, getNextS(current));
            else assignNextT(predSource, getNextS(current));
        } else {
            if (source != (TVertexDescriptor) getTarget(predSource)) assignNextS(predSource, getNextT(current));
            else assignNextT(predSource, getNextT(current));
        }
    }
    else {
        if (source != (TVertexDescriptor) getTarget(current)) value(g.data_vertex, source) = getNextS(current);
        else value(g.data_vertex, source) = getNextT(current);
    }

    // Relink the next pointer of target predecessor
    if (predTarget != (TEdgeStump*) 0) {
        if (target != (TVertexDescriptor) getTarget(current)) {
            if (target != (TVertexDescriptor) getTarget(predTarget)) assignNextS(predTarget, getNextS(current));
            else assignNextT(predTarget, getNextS(current));
        } else {
            if (target != (TVertexDescriptor) getTarget(predTarget)) assignNextS(predTarget, getNextT(current));
            else assignNextT(predTarget, getNextT(current));
        }
    }
    else {
        if (target != (TVertexDescriptor) getTarget(current)) value(g.data_vertex, target) = getNextS(current);
        else value(g.data_vertex, target) = getNextT(current);
    }

    // Deallocate
    releaseId(g.data_id_managerE, _getId(current));
    valueDestruct(current);
    deallocate(g.data_allocator, current, 1);
}

//////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TSpec, typename TVertexDescriptor>
inline void
removeOutEdges(Graph<Undirected<TCargo, TSpec> >& g,
               TVertexDescriptor const v)
{
    typedef Graph<Undirected<TCargo, TSpec> > TGraph;
    typedef typename EdgeType<TGraph>::Type TEdgeStump;
    typedef typename EdgeDescriptor<TGraph>::Type TEdgeDescriptor;
    TEdgeDescriptor eD = g.data_vertex[v];
    while(eD != (TEdgeStump*) 0) {
        removeEdge(g,eD);
        eD = g.data_vertex[v];
    }
}

//////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TSpec, typename TVertexDescriptor>
inline void
removeInEdges(Graph<Undirected<TCargo, TSpec> >& g,
               TVertexDescriptor const v)
{
    removeOutEdges(g,v);
}

//////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TSpec, typename TEdgeDescriptor>
inline typename VertexDescriptor<Graph<Undirected<TCargo, TSpec> > >::Type
targetVertex(Graph<Undirected<TCargo, TSpec> > const&,
             TEdgeDescriptor const edge)
{
    return getTarget(edge);
}

//////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TSpec, typename TEdgeDescriptor>
inline typename VertexDescriptor<Graph<Undirected<TCargo, TSpec> > >::Type
sourceVertex(Graph<Undirected<TCargo, TSpec> > const&,
             TEdgeDescriptor const edge)
{
    return getSource(edge);
}


//////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TSpec, typename TMatrix>
inline void
getAdjacencyMatrix(Graph<Undirected<TCargo, TSpec> > const& g,
                   TMatrix& mat)
{
    typedef Graph<Undirected<TCargo, TSpec> > TGraph;
    typedef typename VertexDescriptor<TGraph>::Type TVertexDescriptor;
    typedef typename EdgeType<TGraph>::Type TEdgeStump;
    typedef typename Size<TMatrix>::Type TSize;
    TSize len = getIdUpperBound(g.data_id_managerV);
    resize(mat, len*len, 0);

    typedef typename Iterator<String<TEdgeStump*> const, Standard>::Type TIterConst;
    TIterConst it = begin(g.data_vertex, Standard());
    TIterConst itEnd = end(g.data_vertex, Standard());
    TVertexDescriptor pos = 0;
    for(;it!=itEnd;++it, ++pos) {
        TVertexDescriptor sourceV = pos;
        TEdgeStump* current = *it;
        while(current!=0) {
            TVertexDescriptor adjV = getTarget(current);
            if (adjV != sourceV) {
                ++mat[sourceV*len+adjV];
                current=getNextS(current);
            } else {
                adjV = getSource(current);
                ++mat[sourceV*len+adjV];
                current=getNextT(current);
            }
        }
    }
}

//////////////////////////////////////////////////////////////////////////////

template<typename TCargo, typename TSpec, typename TVertexDescriptor>
inline typename EdgeDescriptor<Graph<Undirected<TCargo, TSpec> > >::Type
findEdge(Graph<Undirected<TCargo, TSpec> > const& g,
         TVertexDescriptor const v,
         TVertexDescriptor const w)
{
    SEQAN_ASSERT(idInUse(g.data_id_managerV, v));
    SEQAN_ASSERT(idInUse(g.data_id_managerV, w));

    typedef Graph<Undirected<TCargo, TSpec> > TGraph;
    typedef typename EdgeType<TGraph>::Type TEdgeStump;

    TEdgeStump* current = g.data_vertex[v];
    while(current != (TEdgeStump*) 0) {
        TVertexDescriptor adjV = getTarget(current);
        if (adjV != v) {
            if ( adjV == w) return current;
            current=getNextS(current);
        } else {
            adjV = getSource(current);
            if ( adjV == w) return current;
            current=getNextT(current);
        }
    }
    return 0;
}

//////////////////////////////////////////////////////////////////////////////

template <typename TFile, typename TCargo, typename TSpec>
inline void
write(TFile & target,
      Graph<Undirected<TCargo, TSpec> > const& g)
{
//IOREV _nodoc_
    typedef Graph<Undirected<TCargo, TSpec> > TGraph;
    typedef typename VertexDescriptor<TGraph>::Type TVertexDescriptor;
    typedef typename EdgeType<TGraph>::Type TEdgeStump;
    typedef typename Iterator<String<TEdgeStump*> const, Standard>::Type TIterConst;
    TIterConst it = begin(g.data_vertex, Standard());
    TIterConst itEnd = end(g.data_vertex, Standard());
    write(target, "Adjacency list:\n");
    TVertexDescriptor pos = 0;
    for(;it != itEnd; ++it, ++pos) {
        TVertexDescriptor sourceV = pos;
        appendNumber(target, (int)sourceV);
        write(target, " -> ");
        TEdgeStump* current = *it;
        while(current!=0) {
            TVertexDescriptor adjV = getTarget(current);
            if (adjV != sourceV) {
                appendNumber(target, (int)adjV);
                writeValue(target, ',');
                current=getNextS(current);
            } else {
                adjV = getSource(current);
                appendNumber(target, (int)adjV);
                writeValue(target, ',');
                current=getNextT(current);
            }
        }
        writeValue(target, '\n');
    }
    it = begin(g.data_vertex, Standard());
    pos = 0;
    write(target, "Edge list:\n");
    for(; it != itEnd; ++it, ++pos) {
        TVertexDescriptor sourceV = pos;
        TEdgeStump* current = *it;
        while(current!=0) {
            TVertexDescriptor targetV = getTarget(current);
            if (sourceV != targetV) {
                write(target, "Source: ");
                appendNumber(target, (int)sourceV);
                writeValue(target, ',');
                write(target, "Target: ");
                appendNumber(target, (int)targetV);
                writeValue(target, ' ');
                write(target, "(Id: ");
                appendNumber(target, (int)_getId(current));
                writeValue(target, ')');
                writeValue(target, '\n');
                current=getNextS(current);
            } else {
                current=getNextT(current);
            }
        }
    }
}


}// namespace seqan

#endif //#ifndef SEQAN_HEADER_...
