BoostGraph.icc

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/*
    Copyright (c) 2002-2010 Tampere University.
 
    This file is part of TTA-Based Codesign Environment (TCE).
 
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/**
 * @file BoostGraph.icc
 *
 * Boost-based templated implementation of graph base class.
 * In-line implementation of templated methods.
 *
 * @author Andrea Cilio 2005 (cilio-no.spam-cs.tut.fi)
 * @author Vladimir Guzma 2006 (vladimir.guzma-no.spam-tut.fi)
 * @author Heikki Kultala 2007-2010
 * @author Pekka Jääskeläinen 2009-2010
 * @note rating: red
 */
 
#include <queue>
#include <map>
#include <algorithm>
#include <climits>
#include <boost/version.hpp>
#include <boost/format.hpp>
 
#include "CompilerWarnings.hh"
IGNORE_COMPILER_WARNING("-Wunused-parameter")
IGNORE_CLANG_WARNING("-Wunused-local-typedef")
#include <boost/graph/topological_sort.hpp>
 
#if BOOST_VERSION < 104000
#include <boost/property_map.hpp>
#else
#include <boost/property_map/property_map.hpp>
#endif
 
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/graphviz.hpp>
#include <boost/graph/johnson_all_pairs_shortest.hpp>
POP_CLANG_DIAGS
POP_COMPILER_DIAGS
 
#include "Conversion.hh"
#include "AssocTools.hh"
#include "Application.hh"
#include "SetTools.hh"
#include "hash_map.hh"
 
/**
 * Constructor
 *
 */
template <typename GraphNode, typename GraphEdge>
BoostGraph<GraphNode, GraphEdge>::BoostGraph(bool allowLoopEdges) :
    height_(-1), parentGraph_(NULL), sgCounter_(0), 
    allowLoopEdges_(allowLoopEdges), pathCache_(NULL) {}
 
/**
 * Constructor
 *
 */
template <typename GraphNode, typename GraphEdge>
BoostGraph<GraphNode, GraphEdge>::BoostGraph(
    const TCEString& name, bool allowLoopEdges) :
    height_(-1), parentGraph_(NULL), name_(name), sgCounter_(0),
    allowLoopEdges_(allowLoopEdges), pathCache_(NULL) {}
 
/**
 * Copy constructor
 *
 */
template <typename GraphNode, typename GraphEdge>
BoostGraph<GraphNode, GraphEdge>::BoostGraph(
    const BoostGraph<GraphNode, GraphEdge>& other, bool allowLoopEdges) :
    GraphBase<GraphNode, GraphEdge>(), height_(other.height_),
    parentGraph_(NULL) , name_(other.name()), sgCounter_(0),
    allowLoopEdges_(allowLoopEdges), pathCache_(NULL) {
 
    // table which node of other
    std::map<GraphNode*, GraphNode*> nodeMap;
 
    for (int i = 0; i < other.nodeCount(); i++) {
        GraphNode& currNode = other.node(i);
        if (nodeMap.find(&currNode) == nodeMap.end()){
            nodeMap[&currNode] =
                dynamic_cast<GraphNode*>(currNode.clone());
            addNode(*nodeMap[&currNode]);
        }
 
        GraphNode* ourTail = nodeMap[&currNode];
 
        // copy all out edges of the node
        EdgeSet outs = other.outEdges(currNode);
        typename EdgeSet::iterator iter;
        for (iter = outs.begin(); iter != outs.end(); iter++) {
            GraphEdge* outEdge = *iter;
            GraphNode& headNode = other.headNode(*outEdge);
 
            if (nodeMap.find(&headNode) == nodeMap.end()){
                nodeMap[&headNode] =
                    dynamic_cast<GraphNode*>(headNode.clone());
                addNode(*nodeMap[&headNode]);
            }
 
            GraphNode* ourHead = nodeMap[&headNode];
            GraphEdge* ourEdge = dynamic_cast<GraphEdge*>(outEdge->clone());
 
            connectNodes(*ourTail, *ourHead, *ourEdge);
        }
    }
}
 
/**
 * Destructor
 *
 * This automatically deletes all edges that have been in the graph.
 * Those should not be deleted by destructors of deleted graphs.
 */
template <typename GraphNode, typename GraphEdge>
BoostGraph<GraphNode, GraphEdge>::~BoostGraph() {
    if (parentGraph_ != NULL) {
        parentGraph_->detachSubgraph(*this);
    }
    for (typename std::set<GraphEdge*>::iterator i = ownedEdges_.begin();
         i != ownedEdges_.end(); i++) {
        delete *i;
    }
    delete pathCache_;
    pathCache_ = NULL;
}
 
/**
 * Adds a node to the graph.
 *
 * Once added, a node is owned and managed by the graph.
 *
 * Adding a node does not add it to the subgraphs of a graph,
 * but does add into the parent graph.
 *
 * @param node Node to be added.
 */
template <typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::addNode(GraphNode& node) {
    NodeDescriptor nd = boost::add_vertex(&node, graph_);
    nodeDescriptors_[&node] = nd;
 
    if (height_ != -1) {
        sourceDistances_[&node] = 0;
        sinkDistances_[&node] = 0;
 
        loopingSourceDistances_[&node] = 0;
        loopingSinkDistances_[&node] = 0;
    }
 
    // add node also to parent graph
    if (parentGraph_ != NULL) {
        parentGraph_->addNode(node);
    }
}
 
/**
 * Returns the number of nodes contained in this graph.
 *
 * @returns The number of nodes.
 */
template <typename GraphNode, typename GraphEdge>
int
BoostGraph<GraphNode, GraphEdge>::nodeCount() const {
    return boost::num_vertices(graph_);
}
 
/**
 * Returns the number of edges contained in this graph.
 *
 * @returns The number of edges.
 */
template <typename GraphNode, typename GraphEdge>
int
BoostGraph<GraphNode, GraphEdge>::edgeCount() const {
    return boost::num_edges(graph_);
}
 
/**
 * Returns the node of the graph identified by the given index.
 *
 * Notice that the index is not constant. If nodes are added or removed from
 * the graph, the index of an untouched node may change.
 *
 * @param index Index of a node of the graph.
 * @returns The node currently identified by the given index.
 * @exception OutOfRange If the given index is negative, or is not smaller
 *     than the number of nodes of the graph.
 */
template <typename GraphNode, typename GraphEdge>
GraphNode&
BoostGraph<GraphNode, GraphEdge>::node(const int index) const {
    return node(index, true);
}
 
/**
 * Returns the node of the graph identified by the given index.
 *
 * Notice that the index is not constant. If nodes are added or removed from
 * the graph, the index of an untouched node may change.
 *
 * @param index Index of a node of the graph.
 * @returns The node currently identified by the given index.
 * @exception OutOfRange If the given index is negative, or is not smaller
 *     than the number of nodes of the graph.
 */
template <typename GraphNode, typename GraphEdge>
GraphNode&
BoostGraph<GraphNode, GraphEdge>::node(
    const int index, bool cacheResult) const {
    if (index < 0 || index >=  nodeCount()) {
        TCEString procName("BoostGraph::node");
        boost::format errorMsg("Node index %1% out of range [0, %2%).");
        errorMsg % index % nodeCount();
        throw OutOfRange(__FILE__, __LINE__, procName, errorMsg.str());
    }
    NodeDescriptor nd = boost::vertex(index, graph_);
    Node* n = graph_[nd];
    if (cacheResult) {
        nodeDescriptors_[n] = nd;
    }
    return *n;
}
 
/**
 * Returns the edge of the graph identified by the given index.
 *
 * Notice that the index is not constant. If edges are added or removed from
 * the graph, the index of an untouched edge may change.
 *
 * Running time of this function is O(n) where n is the number of edges.
 *
 * @param index Index of an edge of the graph.
 * @returns The edge currently identified by the given index.
 * @exception OutOfRange If the given index is negative, or is not smaller
 *     than the number of edges of the graph.
 */
template <typename GraphNode, typename GraphEdge>
GraphEdge&
BoostGraph<GraphNode, GraphEdge>::edge(const int index) const {
    if (index < 0 || index >=  edgeCount()) {
        TCEString procName("BoostGraph::edge");
        boost::format errorMsg("Edge index %1% out of range [0, %2%).");
        errorMsg % index % edgeCount();
        throw OutOfRange(__FILE__, __LINE__, procName, errorMsg.str());
    }
 
    typedef std::pair<EdgeIter, EdgeIter> EdgeIterPair;
    EdgeIterPair edges = boost::edges(graph_);
    int counter = 0;
    for (EdgeIter i = edges.first; i != edges.second; i++) {
        if (counter == index) {
            GraphEdge* theEdge = graph_[*i];
            return *theEdge;
        }
        counter++;
    }
    assert(false);
    // keep pedantic compilers quiet
    return *graph_[*edges.second];
}
 
/**
 * Returns the n:th outgoing edge from a given node.
 *
 * Warning: this function is slow. When iterating over all outgoing edges
 * of a node, use outEdges instead.
 *
 * @param node Node whose outgoing edges we are searching
 * @param index index of outgoing edge being asked
 * @return The edge.
 */
template <typename GraphNode, typename GraphEdge>
GraphEdge&
BoostGraph<GraphNode, GraphEdge>::outEdge(
    const GraphNode& node, const int index) const {
    const TCEString procName("BoostGraph::outEdge");
 
    if (outDegree(node) <= index) {
        boost::format errorMsg(
            "Outgoing edge at index %1% is out of range. The node "
            "out-degree is %2%.");
        errorMsg % index % outDegree(node);
        throw OutOfRange(__FILE__, __LINE__, procName, errorMsg.str());
    }
 
    std::pair<OutEdgeIter, OutEdgeIter> edges =
        boost::out_edges(descriptor(node), graph_);
    if (edges.first == edges.second) {
        TCEString errorMsg("Node does not belong to this graph.");
        throw InstanceNotFound(__FILE__, __LINE__, procName, errorMsg);
    }
 
    GraphEdge* result = NULL;
    int n = 0;
    for (OutEdgeIter ei = edges.first; ei != edges.second; ei++) {
        if (n == index) {
            result = graph_[(*ei)];
            break;
        } else {
            n++;
        }
    }
    assert(result != NULL);
 
    return *result;
}
 
/**
 * Returns the n:th incoming edge to a given node.
 *
 * Warning: this function is slow. When iterating over all incoming edges
 * of a node, use inEdges instead.
 *
 * @param node Node whose incoming edges we are searching
 * @param index index of incoming edge being asked
 * @return The edge.
 */
template <typename GraphNode, typename GraphEdge>
GraphEdge&
BoostGraph<GraphNode, GraphEdge>::inEdge(
    const GraphNode& node, const int index) const {
    std::pair<InEdgeIter, InEdgeIter> edges =
        boost::in_edges(descriptor(node), graph_);
    if (edges.first == edges.second) {
        const TCEString procName("BoostGraph::inEdge");
        TCEString errorMsg("Node does not belong to this graph.");
        throw InstanceNotFound(__FILE__, __LINE__, __func__, errorMsg);
    }
 
    GraphEdge* result = NULL;
    int n = 0;
    for (InEdgeIter ei = edges.first; ei != edges.second; ei++) {
        if (n == index) {
            result = graph_[(*ei)];
            break;
        } else {
            n++;
        }
    }
    if (result == NULL) {
        boost::format errorMsg(
            "Incoming edge at index %1% is out of range. The node "
            "in-degree is %2%.");
        errorMsg % index % inDegree(node);
        throw OutOfRange(__FILE__, __LINE__, __func__, errorMsg.str());
    }
 
    return *result;
}
 
/**
 * Returns the outgoing edges of a node.
 *
 * @param node A node of the graph.
 * @returns A set of edges.
 */
template <typename GraphNode, typename GraphEdge>
typename BoostGraph<GraphNode, GraphEdge>::EdgeSet
BoostGraph<GraphNode, GraphEdge>::outEdges(const GraphNode& node) const {
    typedef typename GraphTraits::out_edge_iterator outEdgeIter;
    std::pair<outEdgeIter, outEdgeIter> edges = boost::out_edges(
        descriptor(node), graph_);
    EdgeSet result;
    for (outEdgeIter ei = edges.first; ei != edges.second; ei++) {
        GraphEdge* edge = graph_[(*ei)];
        // add to descriptor cache.
        edgeDescriptors_[edge] = *ei;
        result.insert(edge);
    }
    return result;
}
 
/**
 * Returns the outgoing edges of a node in the root graph of the
 * subgraph tree.
 *
 * @param node A node of the graph.
 * @returns A set of edges.
 */
template <typename GraphNode, typename GraphEdge>
typename BoostGraph<GraphNode, GraphEdge>::EdgeSet
BoostGraph<GraphNode, GraphEdge>::rootGraphOutEdges(
    const GraphNode& node) const {
    if (parentGraph_ == NULL) {
        return outEdges(node);
    } else {
        return parentGraph_->rootGraphOutEdges(node);
    }
}
 
/**
 * Returns the ingoing edges of a node.
 *
 * @param node A node of the graph.
 * @returns A set of edges.
 */
template <typename GraphNode, typename GraphEdge>
typename BoostGraph<GraphNode, GraphEdge>::EdgeSet
BoostGraph<GraphNode, GraphEdge>::inEdges(const GraphNode& node) const {
    typedef typename GraphTraits::in_edge_iterator InEdgeIter;
    std::pair<InEdgeIter, InEdgeIter> edges = boost::in_edges(
        descriptor(node), graph_);
    EdgeSet result;
    for (InEdgeIter ei = edges.first; ei != edges.second; ++ei) {
        GraphEdge* edge = graph_[(*ei)];
        edgeDescriptors_[edge] = *ei;
        result.insert(edge);
    }
    return result;
}
 
/**
 * Returns the ingoing edges of a node in the root graph of the subgraph tree.
 *
 * @param node A node of the graph.
 * @returns A set of edges.
 */
template <typename GraphNode, typename GraphEdge>
typename BoostGraph<GraphNode, GraphEdge>::EdgeSet
BoostGraph<GraphNode, GraphEdge>::rootGraphInEdges(
    const GraphNode& node) const {
    if (parentGraph_ == NULL) {
        return inEdges(node);
    } else {
        return parentGraph_->rootGraphInEdges(node);
    }
}
 
/**
 * Returns the ingoing edge of a node in the root graph of the subgraph tree.
 *
 * @param node A node of the graph.
 * @param index index of edge.
 * @return the edge edges.
 */
template <typename GraphNode, typename GraphEdge>
typename BoostGraph<GraphNode, GraphEdge>::Edge&
BoostGraph<GraphNode, GraphEdge>::rootGraphInEdge(
    const GraphNode& node, const int index) const {
    if (parentGraph_ == NULL) {
        return inEdge(node, index);
    } else {
        return parentGraph_->rootGraphInEdge(node, index);
    }
}
 
/**
 * Returns the outgoing edge of a node in the root graph of the subgraph tree.
 *
 * @param node A node of the graph.
 * @param index index of edge.
 * @return the edge.
 */
template <typename GraphNode, typename GraphEdge>
typename BoostGraph<GraphNode, GraphEdge>::Edge&
BoostGraph<GraphNode, GraphEdge>::rootGraphOutEdge(
    const GraphNode& node, const int index) const {
    if (parentGraph_ == NULL) {
        return outEdge(node, index);
    } else {
        return parentGraph_->rootGraphOutEdge(node, index);
    }
}
 
/**
 * Returns the output degree of a node, that is, the number of outgoing edges
 * of a node.
 *
 * @param node A node of the graph.
 * @returns A set of edges.
 * @exception InstanceNotFound if the node does not belong to this graph.
 */
template <typename GraphNode, typename GraphEdge>
int
BoostGraph<GraphNode, GraphEdge>::outDegree(const GraphNode& node) const {
    return boost::out_degree(descriptor(node), graph_);
}
 
/**
 * Returns the input degree of a node, that is, the number of incoming edges
 * of a node.
 *
 * @param node A node of the graph.
 * @returns A set of edges.
 * @exception InstanceNotFound if the node does not belong to this graph.
 */
template <typename GraphNode, typename GraphEdge>
int
BoostGraph<GraphNode, GraphEdge>::inDegree(const GraphNode& node) const {
    return boost::in_degree(descriptor(node), graph_);
}
 
/**
 * Returns the output degree of a node, that is, the number of outgoing edges
 * of a node in the root graph of the subgraph tree
 *
 * @param node A node of the graph.
 * @returns A set of edges.
 * @exception InstanceNotFound if the node does not belong to this graph.
 */
template <typename GraphNode, typename GraphEdge>
int
BoostGraph<GraphNode, GraphEdge>::rootGraphOutDegree(
    const GraphNode& node) const {
    return parentGraph_ == NULL ?
        boost::out_degree(descriptor(node), graph_) :
        parentGraph_->rootGraphOutDegree(node);
}
 
/**
 * Returns the input degree of a node, that is, the number of incoming edges
 * of a node in the root graph of the subgraph tree
 *
 * @param node A node of the graph.
 * @returns A set of edges.
 * @exception InstanceNotFound if the node does not belong to this graph.
 */
template <typename GraphNode, typename GraphEdge>
int
BoostGraph<GraphNode, GraphEdge>::rootGraphInDegree(
    const GraphNode& node) const {
    return parentGraph_ == NULL ?
        boost::in_degree(descriptor(node), graph_) :
        parentGraph_->rootGraphInDegree(node);
}
 
/**
 * Returns the tail node of a edge.
 *
 * Warning: this function is slow, O(n) to number of edges in the graph.
 *
 * @param edge Edge whose tail node we are asking
 * @return The tail node of the given edge
 */
template <typename GraphNode, typename GraphEdge>
GraphNode&
BoostGraph<GraphNode, GraphEdge>::tailNode(const GraphEdge& edge) const {
    EdgeDescriptor ed = descriptor(edge);
    NodeDescriptor nd = boost::source(ed, graph_);
    GraphNode* nn = graph_[nd];
    nodeDescriptors_[nn] = nd;
    return *nn;
}
 
/**
 * Returns the tail node of a edge.
 *
 * This is faster but uglier version of the function.
 *
 * @param edge Edge whose tail node we are asking
 * @return The tail node of the given edge
 */
template <typename GraphNode, typename GraphEdge>
GraphNode&
BoostGraph<GraphNode, GraphEdge>::tailNode(
    const GraphEdge& edge, const NodeDescriptor& headNode) const {
    EdgeDescriptor ed = edgeDescriptor(edge, headNode);
    NodeDescriptor nd = boost::source(ed, graph_);
    GraphNode* nn = graph_[nd];
    nodeDescriptors_[nn] = nd;
    return *nn;
}
 
/**
 * Returns the head node of a edge.
 *
 * Warning: this function is slow, O(n) to number of edges in the graph.
 *
 * @param edge Edge whose head node we are asking
 * @return The head node of the given edge
 */
template <typename GraphNode, typename GraphEdge>
GraphNode&
BoostGraph<GraphNode, GraphEdge>::headNode(const GraphEdge& edge) const {
    EdgeDescriptor ed = descriptor(edge);
    NodeDescriptor nd = boost::target(ed, graph_);
    GraphNode* node = graph_[nd];
    nodeDescriptors_[node] = nd;
    return *node;
}
 
/**
 * Returns the head node of a edge.
 *
 * This is faster but uglier version of the function.
 *
 * @param edge Edge whose head node we are asking
 * @return The head node of the given edge
 */
template <typename GraphNode, typename GraphEdge>
GraphNode&
BoostGraph<GraphNode, GraphEdge>::headNode(
    const GraphEdge& edge, const NodeDescriptor& tailNode) const {
    EdgeDescriptor ed = edgeDescriptor(tailNode,edge);
    NodeDescriptor nd = boost::target(ed, graph_);
    GraphNode* node = graph_[nd];
    nodeDescriptors_[node] = nd;
    return *node;
}
 
/**
 * Connects two nodes and attaches the given properties to the new graph
 * edge connecting the nodes.
 *
 * Once registered into a graph connection, the edge properties are owned
 * and managed by the graph. This method can be invoked repeatedly on the
 * same pair of nodes; each time it will create a new (parallel) edge.
 *
 * @param nTail Tail node of the connection.
 * @param nHead Head node of the connection.
 * @param e Properties of the connecting edge.
 */
template <typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::connectNodes(
    const GraphNode& nTail, const GraphNode& nHead, GraphEdge& e) {
    connectNodes(nTail, nHead, e, NULL);
}
 
template <typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::calculatePathLengthsOnConnect(
    const GraphNode& nTail, const GraphNode& nHead, GraphEdge& e) {
 
    if (height_ == -1) {
        return;
    }
    int eWeight = edgeWeight(e, nHead);
    auto loopingHeadIter = loopingSinkDistances_.find(&nHead);
    auto loopingTailIter = loopingSourceDistances_.find(&nTail);
    auto headIter = sinkDistances_.find(&nHead);
    auto tailIter = sourceDistances_.find(&nTail);
 
    if (loopingHeadIter != loopingSinkDistances_.end() &&
        !e.isBackEdge()) {
        calculateSinkDistance(
            nTail, loopingHeadIter->second + eWeight, true);
    }
 
    if (headIter == sinkDistances_.end()) {
        sinkDistances_[&nHead] = 0;
        calculateSinkDistance(nTail, eWeight, e.isBackEdge());
    } else {
        calculateSinkDistance(
            nTail, headIter->second + eWeight, e.isBackEdge());
    }
 
    if (loopingTailIter != loopingSourceDistances_.end() &&
        !e.isBackEdge()) {
        calculateSourceDistances(
            &nHead, loopingTailIter->second + eWeight, true);
    }
 
    if (tailIter == sourceDistances_.end()) {
        sourceDistances_[&nTail] = 0;
        calculateSourceDistances(&nHead, eWeight, e.isBackEdge());
    } else {
        calculateSourceDistances(
                    &nHead, tailIter->second + eWeight, e.isBackEdge());
    }
}
 
/**
 * Connects two nodes and attaches the given properties to the new graph
 * edge connecting the nodes.
 *
 * Once registered into a graph connection, the edge properties are owned
 * and managed by the graph. This method can be invoked repeatedly on the
 * same pair of nodes; each time it will create a new (parallel) edge.
 *
 * @param nTail Tail node of the connection.
 * @param nHead Head node of the connection.
 * @param e Properties of the connecting edge.
 * @param modifier sub-or parent Graph which caused this procedure to be called
 */
template <typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::connectNodes(
    const GraphNode& nTail, const GraphNode& nHead, GraphEdge& e,
    GraphBase<GraphNode, GraphEdge>* modifier, bool creatingSG) {
    // not add if invalid params
    if (!hasNode(nTail) || !hasNode(nHead)) {
        // for sub graphs silently skip it
        if (parentGraph_ != NULL) {
            return;
        } else {
            assert(hasNode(nTail)
                && "Trying to connect tail node not on the graph");
            assert(hasNode(nHead)
                && "Trying to connect head node not on the graph");
        }
    }
 
    if (hasEdge(nTail, nHead, e)) {
        TCEString procName("BoostGraph::addEdge");
        TCEString errorMsg("Edge already belongs to this graph.");
        throw ObjectAlreadyExists(__FILE__, __LINE__, procName, errorMsg);
    }
 
    if (parentGraph_ == NULL && !creatingSG) {
        ownedEdges_.insert(&e);
    }
 
    if (allowLoopEdges_ || !e.isBackEdge()) {
        NodeDescriptor td = descriptor(nTail);
        NodeDescriptor hd = descriptor(nHead);
        if (!e.isBackEdge() && td == hd && creatingSG) {
            std::cerr << "node: " << nTail.toString() << " edge: " << e.toString() << std::endl;
            assert(0 && "non-loop-edge going from node to itsefl!");
        }
        edgeDescriptors_[&e] =
            boost::add_edge(td, hd, &e, graph_).
            first;
 
        // If we have calculated path lenght data, keep it in sync.
        if (height_ != -1) {
            calculatePathLengthsOnConnect(nTail, nHead, e);
        }
    }
 
    if (parentGraph_ != NULL && parentGraph_ != modifier) {
        parentGraph_->connectNodes(nTail, nHead, e, this);
    }
 
    for (unsigned int i = 0; i < childGraphs_.size(); i++) {
        if ( childGraphs_[i] != modifier ) {
            childGraphs_[i]->connectNodes(nTail, nHead, e, this);
        }
    }
}
 
template<typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::sinkDistDecreased(
const GraphNode& n) const {
 
    if (height_ == -1) {
        return;
    }
 
    auto lsdIter = loopingSinkDistances_.find(&n);
    int oldSD = sinkDistances_[&n];
    int oldLSD = lsdIter != loopingSinkDistances_.end() ?
        lsdIter->second : 0;
    int sd = 0;
    int loopingSD = 0;
    int nd = descriptor(n);
    auto edges = boost::out_edges(nd, graph_);
    for (auto j = edges.first; j != edges.second; j++) {
        EdgeDescriptor ed = *j;
        NodeDescriptor hd = boost::target(ed, graph_);
        GraphNode* head = graph_[hd];
        GraphEdge* edge = graph_[ed];
        int eWeight = edgeWeight(*edge, *head);
        int headSD = sinkDistances_[head] + eWeight;
        if (edge->isBackEdge()) {
            loopingSD = std::max(loopingSD, headSD);
        } else {
            sd = std::max(sd, headSD);
            auto headLSDIter = loopingSinkDistances_.find(head);
            if (headLSDIter != loopingSinkDistances_.end()) {
                loopingSD = std::max(
                    loopingSD, headLSDIter->second + eWeight);
            }
        }
    }
    if (sd < oldSD || loopingSD < oldLSD) {
        sinkDistances_[&n] = sd;
        if (loopingSD < oldLSD) {
            loopingSinkDistances_[&n] = loopingSD;
        }
 
        // propagate to predecessors
        auto edges = boost::in_edges(nd, graph_);
        for (auto j = edges.first; j != edges.second; j++) {
            EdgeDescriptor ed = *j;
            GraphEdge* edge = graph_[ed];
            if (!edge->isBackEdge() || sd < oldSD) {
                NodeDescriptor td = boost::source(ed, graph_);
                GraphNode* tail = graph_[td];
                sinkDistDecreased(*tail);
            }
        }
    }
}
 
template<typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::sourceDistDecreased(
    const GraphNode& n) const {
 
    if (height_ == -1) {
        return;
    }
 
    auto lsdIter = loopingSourceDistances_.find(&n);
    int oldSD = sourceDistances_[&n];
    int oldLSD = lsdIter != loopingSourceDistances_.end() ?
        lsdIter->second : 0;
 
    int sd = 0;
    int loopingSD = 0;
    int nd = descriptor(n);
    auto edges = boost::in_edges(nd, graph_);
    for (auto j = edges.first; j != edges.second; j++) {
        EdgeDescriptor ed = *j;
        NodeDescriptor td = boost::source(ed, graph_);
        GraphNode* tail = graph_[td];
        GraphEdge* edge = graph_[ed];
        int eWeight = edgeWeight(*edge, n);
        int tailSD = sourceDistances_[tail] + eWeight;
        if (edge->isBackEdge()) {
            loopingSD = std::max(loopingSD, tailSD);
        } else {
            sd = std::max(sd, tailSD);
            auto tailLSDIter = loopingSourceDistances_.find(tail);
            if (tailLSDIter != loopingSourceDistances_.end()) {
                loopingSD = std::max(
                    loopingSD, tailLSDIter->second + eWeight);
            }
        }
    }
 
    if (sd < oldSD || loopingSD < oldLSD) {
        sourceDistances_[&n] = sd;
        if (loopingSD < oldLSD) {
            loopingSourceDistances_[&n] = loopingSD;
        }
 
        // propagate to successors
        auto edges = boost::out_edges(nd, graph_);
        for (auto j = edges.first; j != edges.second; j++) {
            EdgeDescriptor ed = *j;
            GraphEdge* edge = graph_[ed];
            if (!edge->isBackEdge() || sd < oldSD) {
                NodeDescriptor hd = boost::target(ed, graph_);
                GraphNode* head = graph_[hd];
                sourceDistDecreased(*head);
            }
        }
    }
}
 
/**
 * Disconnects two nodes.
 *
 * All edges between the given nodes are deleted. It is not an error to
 * invoke this method on a pair of nodes that are not connected.
 *
 * @param nTail Tail node of the connection.
 * @param nHead Head node of the connection.
 */
template <typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::disconnectNodes(
    const GraphNode& nTail,
    const GraphNode& nHead) {
 
    int maxW = 0;
    int maxwLoop = 0;
    while (hasEdge(nTail, nHead)) {
        EdgeDescriptor ed = connectingEdge(nTail, nHead);
        GraphEdge* e = graph_[ed];
        if (height_ != -1) {
            int eWeight = edgeWeight(*e, nHead);
            if (e->isBackEdge()) {
                maxwLoop = std::max(eWeight, maxW);
            } else {
                maxW = std::max(eWeight, maxW);
            }
        }
        removeEdge(*e, &nTail, &nHead);
    }
 
    if (height_ != -1) {
        bool recalc = false;
        if (sourceDistances_[&nTail] + maxW ==
            sourceDistances_[&nHead] ||
            (!loopingSourceDistances_.empty() &&
             (loopingSourceDistances_[&nTail] + maxW ==
              loopingSourceDistances_[&nHead] ||
              sourceDistances_[&nTail] + maxwLoop ==
              loopingSourceDistances_[&nHead]))) {
            recalc = true;
            sourceDistDecreased(nTail);
        }
 
        if (!sinkDistances_.empty() &&
            (sinkDistances_[&nHead] + maxW ==
             sinkDistances_[&nTail] ||
             (!loopingSinkDistances_.empty() &&
              (loopingSinkDistances_[&nHead] + maxW ==
               loopingSinkDistances_[&nTail] ||
               sinkDistances_[&nHead] +maxwLoop ==
               loopingSinkDistances_[&nTail])))) {
            recalc = true;
            sinkDistDecreased(nHead);
        }
 
        if (recalc) {
            delete pathCache_;
            pathCache_ = NULL;
        }
    }
}
 
/**
 * Moves all incoming edges from a node to another node.
 *
 * This reuses the origial Edge objects, thus should retain the original
 * properties (even if defined in a derived class).
 *
 * @param source The node to move the incoming edges from.
 * @param destination The node to move the incoming edges to.
 */
template <typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::moveInEdges(
    const GraphNode& source, const GraphNode& destination) {
    moveInEdges(source, destination, NULL);
}
 
/**
 * Moves all incoming edges from a node to another node.
 *
 * This reuses the origial Edge objects, thus should retain the original
 * properties (even if defined in a derived class).
 *
 * @param source The node to move the incoming edges from.
 * @param destination The node to move the incoming edges to.
 */
template <typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::moveInEdges(
    const GraphNode& source, const GraphNode& destination,
    BoostGraph* modifierGraph) {
    if (!hasNode(source)) {
        if (hasNode(destination)) {
            TCEString msg = "Illegal Graph update: "
                "copying edges from outside of the graph";
            throw NotAvailable(__FILE__,__LINE__,__func__, msg);
        } else {
            return; // no need to do anything
        }
 
    } else {
        EdgeSet edges = inEdges(source);
        for (typename EdgeSet::iterator i = edges.begin();
             i != edges.end(); ++i) {
            Edge& e = **i;
            const GraphNode& tail = tailNode(e);
            const GraphNode& head = destination;
            boost::remove_edge(descriptor(e), graph_);
 
            typename EdgeDescMap::iterator
                edIter = edgeDescriptors_.find(&e);
            if (edIter != edgeDescriptors_.end()) {
                edgeDescriptors_.erase(edIter);
            }
 
            sourceDistDecreased(source);
            sinkDistDecreased(tail);
 
            // if dest not in this graph, just remove
            if (hasNode(destination)) {
                std::pair<EdgeDescriptor,bool> tmpPair =
                    boost::add_edge(
                        descriptor(tail), descriptor(head), &e, graph_);
                edgeDescriptors_[&e] = tmpPair.first;
 
                if (height_ != -1) {
                    calculatePathLengthsOnConnect(tail, head, e);
                }
 
            }
        }
 
        // update parent- and childgraphs
        if (parentGraph_ != NULL && parentGraph_ != modifierGraph) {
            parentGraph_->moveInEdges(
                source, destination, this);
        }
 
        for (unsigned int i = 0; i < childGraphs_.size(); i++) {
            if (childGraphs_.at(i) != modifierGraph ) {
                childGraphs_.at(i)->moveInEdges(
                    source, destination, this);
            }
        }
    }
}
 
template <typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::copyInEdge(
    const GraphNode& destination,
    GraphEdge& edge,
    const GraphNode* tail) {
        // start from the root tree.
    BoostGraph<GraphNode,GraphEdge>* rg = rootGraph();
    if (tail == NULL) {
        tail = &rg->tailNode(edge);
    }
    Edge* newEdge = new Edge(edge);
    rg->connectNodes(*tail, destination, *newEdge);
}
 
template <typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::copyOutEdge(
//    const GraphNode& source,
    const GraphNode& destination,
    GraphEdge& edge,
    const GraphNode* head) {
        // start from the root tree.
    BoostGraph<GraphNode,GraphEdge>* rg = rootGraph();
    if (head == NULL) {
        head = &rg->headNode(edge);
    }
    Edge* newEdge = new Edge(edge);
    rg->connectNodes(destination, *head, *newEdge);
}
 
/**
 * Moves an edge which comes into source node to point into another node.
 */
template <typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::moveInEdge(
    const GraphNode& originalHeadNode,
    const GraphNode& newHeadNode,
    GraphEdge& edge,
    const GraphNode* tail,
    bool childs) {
 
    // start from the root tree.
    if (!childs) {
        BoostGraph<GraphNode,GraphEdge>* rg = rootGraph();
        if (tail == NULL) {
            tail = &rg->tailNode(edge);
        }
        rg->moveInEdge(originalHeadNode, newHeadNode, edge, tail, true);
        return;
    }
 
    if (hasNode(*tail) && hasEdge(edge)) {
        bool hasSource = hasNode(originalHeadNode);
        bool hasDestination = hasNode(newHeadNode);
        const GraphNode& head = newHeadNode;
 
        if (hasSource) {
            boost::remove_edge(descriptor(edge), graph_);
 
            sourceDistDecreased(originalHeadNode);
            sinkDistDecreased(*tail);
        }
 
        if (hasDestination) {
            std::pair<EdgeDescriptor,bool> tmpPair =
                boost::add_edge(
                    descriptor(*tail), descriptor(head), &edge, graph_);
            edgeDescriptors_[&edge] = tmpPair.first;
 
            if (height_ != -1) {
                calculatePathLengthsOnConnect(*tail, head, edge);
            }
 
        }
        // need to process child graphs?
        if (hasSource | hasDestination) {
            for (unsigned int i = 0; i < childGraphs_.size(); i++) {
                childGraphs_.at(i)->moveInEdge(
                    originalHeadNode, newHeadNode, edge, tail, true);
            }
        }
    }
}
 
/*
 * Moves edge which originally points
 */
template <typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::moveOutEdge(
    const GraphNode& originalTailNode,
    const GraphNode& newTailNode,
    GraphEdge& edge,
    const GraphNode* head,
    bool childs) {
 
    if (!childs) {
        BoostGraph* rg = rootGraph();
        if (head == NULL) {
            head = &rg->headNode(edge);
        }
        rg->moveOutEdge(originalTailNode, newTailNode, edge, head, true);
        return;
    }
 
    if (hasNode(*head) && hasEdge(edge)) {
        bool hasSource = hasNode(originalTailNode);
        bool hasDestination = hasNode(newTailNode);
 
        const GraphNode& tail = newTailNode;
        if (hasSource) {
            boost::remove_edge(descriptor(edge), graph_);
 
            sourceDistDecreased(*head);
            sinkDistDecreased(originalTailNode);
 
        }
 
        if (hasDestination) {
            std::pair<EdgeDescriptor,bool> tmpPair =
                boost::add_edge(
                    descriptor(tail), descriptor(*head), &edge, graph_);
            edgeDescriptors_[&edge] = tmpPair.first;
 
            if (height_ != -1) {
                calculatePathLengthsOnConnect(tail, *head, edge);
            }
 
        }
 
        // need to process child graphs?
        if (hasSource | hasDestination) {
            for (unsigned int i = 0; i < childGraphs_.size(); i++) {
                childGraphs_.at(i)->moveOutEdge(
                    originalTailNode, newTailNode, edge, head, true);
            }
        }
    }
}
 
/**
 * Moves all outgoing edges from a node to another node.
 *
 * This reuses the origial Edge objects, thus should retain the original
 * properties (even if defined in a derived class).
 *
 * @param source The node to move the outgoing edges from.
 * @param destination The node to move the outgoing edges to.
 */
template <typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::moveOutEdges(
    const GraphNode& source, const GraphNode& destination) {
    moveOutEdges(source, destination, this);
}
 
/**
 * Moves all outgoing edges from a node to another node.
 *
 * This reuses the origial Edge objects, thus should retain the original
 * properties (even if defined in a derived class).
 *
 * @param source The node to move the outgoing edges from.
 * @param destination The node to move the outgoing edges to.
 */
template <typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::moveOutEdges(
    const GraphNode& source, const GraphNode& destination,
    BoostGraph* modifierGraph) {
    if (!hasNode(source)) {
        if (hasNode(destination)) {
            TCEString msg = "Illegal Graph update: "
                "copying edges from outside of the graph";
            throw NotAvailable(__FILE__,__LINE__,__func__, msg);
        } else {
            return; // no need to do anything
        }
 
    } else {
        EdgeSet edges = outEdges(source);
        for (typename EdgeSet::iterator i = edges.begin();
             i != edges.end(); ++i) {
            Edge& e = **i;
            const GraphNode& tail = destination;
            const GraphNode& head = headNode(e);
            boost::remove_edge(descriptor(e), graph_);
 
            sourceDistDecreased(head);
            sinkDistDecreased(source);
 
            typename EdgeDescMap::iterator
                edIter = edgeDescriptors_.find(&e);
            if (edIter != edgeDescriptors_.end()) {
                edgeDescriptors_.erase(edIter);
            }
 
            if (hasNode(destination)) {
                std::pair<EdgeDescriptor,bool> tmpPair =
                boost::add_edge(
                    descriptor(tail), descriptor(head), &e, graph_);
                edgeDescriptors_[&e] = tmpPair.first;
 
                if (height_ != -1) {
                    calculatePathLengthsOnConnect(tail, head, e);
                }
 
            }
        }
 
 
        // update parent- and childgraphs
        if (parentGraph_ != NULL && parentGraph_ != modifierGraph) {
            parentGraph_->moveOutEdges(source, destination, this);
        }
 
        for (unsigned int i = 0; i < childGraphs_.size(); i++) {
            if (childGraphs_.at(i) != modifierGraph ) {
                childGraphs_.at(i)->moveOutEdges(source, destination, this);
            }
        }
 
    }
}
 
template <typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::clearDescriptorCache(EdgeSet edges) {
    for (typename EdgeSet::iterator i = edges.begin();
         i != edges.end(); ++i) {
        typename EdgeDescMap::iterator iedi = edgeDescriptors_.find(*i);
        if (iedi != edgeDescriptors_.end()) {
            edgeDescriptors_.erase(iedi);
        }
    }
}
 
/**
 * Removes a node of the graph, without deleting the associated properties.
 *
 * The connection between the given nodes and other nodes are removed from
 * the graph. The property object is not managed by the graph anymore.
 *
 * @param node Properties of the node to be removed.
 * @exception InstanceNotFound If the node propertes are not registered to a
 *     node of the graph.
 */
template <typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::removeNode(
    GraphNode& nodeToRemove, BoostGraph* modifierGraph) {
    if (hasNode(nodeToRemove)) {
 
        replaceNodeWithLastNode(nodeToRemove);
 
        if (parentGraph_ != NULL && parentGraph_ != modifierGraph) {
            parentGraph_->removeNode(nodeToRemove, this);
        }
 
        for (unsigned int i = 0; i < childGraphs_.size(); i++) {
            if (childGraphs_.at(i) != modifierGraph ) {
                childGraphs_.at(i)->removeNode(nodeToRemove, this);
            }
        }
    } else {
        if (parentGraph_ == NULL) {
            TCEString msg = "Node not found in graph, cannot remove";
            throw InstanceNotFound(__FILE__,__LINE__,__func__, msg);
        }
    }
}
 
/**
 * Removes a node of the graph, without deleting the associated properties.
 *
 * The connection between the given nodes and other nodes are removed from
 * the graph. The property object is not managed by the graph anymore.
 *
 * @param node Properties of the node to be removed.
 * @exception InstanceNotFound If the node propertes are not registered to a
 *     node of the graph.
 */
template <typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::removeNode(GraphNode& node) {
    removeNode(node, NULL);
}
 
/**
 * Removes a node of the subgraph, leaving it to the parent graph.
 *
 * Drops node also from all child graphs.
 *
 * @param node Properties of the node to be removed.
 * @exception InstanceNotFound If the node propertes are not registered to a
 *     node of the graph.
 */
template <typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::dropNode(GraphNode& nodeToDrop) {
    if (!hasNode(nodeToDrop)) {
        return;
    }
 
    replaceNodeWithLastNode(nodeToDrop);
 
    for (unsigned int i = 0; i < childGraphs_.size(); i++) {
        childGraphs_.at(i)->dropNode(nodeToDrop);
    }
}
 
/**
 * Replaces a node with properties of the last node and then removes the
 * last node from the graph. This is semantically equal to removing
 * a node from the graph but runs much faster.
 * Does not remove anything from subgraphs.
 *
 * @param dest node to be removed/replaced with last one.
 */
template <typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::replaceNodeWithLastNode(GraphNode& dest) {
 
    NodeDescriptor nd = descriptor(dest);
    typename BoostGraph<GraphNode, GraphEdge>::NodeSet preds;
    typename BoostGraph<GraphNode, GraphEdge>::NodeSet succs;
 
    succs = successors(dest);
    preds = predecessors(dest);
 
    // remove edge cache
    clearDescriptorCache(inEdges(dest));
    clearDescriptorCache(outEdges(dest));
 
    // clear all edges. from to node to remove/drop.
    boost::clear_vertex(nd, graph_);
 
    // Move last node to place of deleted node, then delete last node.
    GraphNode& lastNode = node(nodeCount()-1);
 
    NodeDescriptor lnd = descriptor(lastNode);
    if (&dest != &lastNode) {
        // move in edges from last node to place of deleted node.
        EdgeSet iEdges = inEdges(lastNode);
        for (typename EdgeSet::iterator i = iEdges.begin();
             i != iEdges.end(); ++i) {
            Edge& e = **i;
            const GraphNode& tail = tailNode(e);
            // remove the edge pointing to old place of last node
            boost::remove_edge(descriptor(e), graph_);
 
            // clear descriptor cache for that edge
            typename EdgeDescMap::iterator
                edIter = edgeDescriptors_.find(&e);
            if (edIter != edgeDescriptors_.end()) {
                edgeDescriptors_.erase(edIter);
            }
 
            // add the edge back, pointing to the new place
            // of the last node.
            std::pair<EdgeDescriptor,bool> tmpPair =
                boost::add_edge(
                    descriptor(tail), nd, &e, graph_);
            edgeDescriptors_[&e] = tmpPair.first;
        }
 
        // move out edges. from last node to place of deleted node.
        EdgeSet oEdges = outEdges(lastNode);
        for (typename EdgeSet::iterator i = oEdges.begin();
             i != oEdges.end(); ++i) {
            Edge& e = **i;
            const GraphNode& head = headNode(e);
            // remove the edge pointing to old place of last node
            boost::remove_edge(descriptor(e), graph_);
 
            // clear descriptor cache for that edge
            typename EdgeDescMap::iterator
                edIter = edgeDescriptors_.find(&e);
            if (edIter != edgeDescriptors_.end()) {
                edgeDescriptors_.erase(edIter);
            }
 
            // add the edge back, originating from the new place
            // of the last node.
            std::pair<EdgeDescriptor,bool> tmpPair =
                boost::add_edge(
                    nd, descriptor(head), &e, graph_);
            edgeDescriptors_[&e] = tmpPair.first;
        }
 
        // then move the Node class.
        graph_[nd] = &lastNode;
 
        // update descriptor map.
        nodeDescriptors_[&lastNode] = nd;
    }
 
    if (height_ != -1) {
        sinkDistances_.erase(&dest);
        sourceDistances_.erase(&dest);
        loopingSinkDistances_.erase(&dest);
        loopingSourceDistances_.erase(&dest);
    }
 
    for (auto n: succs) sourceDistDecreased(*n);
    for (auto n: preds) sinkDistDecreased(*n);
 
    nodeDescriptors_[&lastNode] = nd;
 
    // remove just the last node.
    boost::remove_vertex(lnd, graph_);
 
    // remove node from descriptor cache
    typename NodeDescMap::iterator ndi =
        nodeDescriptors_.find(&dest);
    if (ndi != nodeDescriptors_.end()) {
        nodeDescriptors_.erase(ndi);
    }
}
 
/**
 * Removes the edge connecting two nodes of the graph.
 * The associated properties are deleted automatically when
 * the graph is deleted, should not be deleted by the used.
 *
 * The connection between the head and tail nodes corresponding to the given
 * property object is removed from the graph.
 *
 * @param e Properties of the connecting edge to be removed.
 * @exception InstanceNotFound If the edge propertes are not registered to a
 *     connection of the graph.
 */
template <typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::removeEdge(GraphEdge& e) {
    removeEdge(e, NULL, NULL, NULL);
}
 
/**
 * Removes the edge connecting two nodes of the graph from a subgraph,
 * but leaves it into the original graph
 *
 * @param e Properties of the connecting edge to be removed.
 * @exception InstanceNotFound If the edge propertes are not registered to a
 *     connection of the graph.
 
 */
template <typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::dropEdge(GraphEdge& e) {
    boost::remove_edge(descriptor(e), graph_);
 
    typename EdgeDescMap::iterator
        edIter = edgeDescriptors_.find(&e);
    if (edIter != edgeDescriptors_.end()) {
        edgeDescriptors_.erase(edIter);
    }
 
    for (unsigned int i = 0; i < childGraphs_.size(); i++) {
        childGraphs_.at(i)->dropEdge(e);
    }
}
 
/**
 * Removes the edge connecting two nodes of the graph, without deleting the
 * associated properties.
 *
 * The connection between the head and tail nodes corresponding to the given
 * property object is removed from the graph. The property object is not
 * managed by the graph anymore.
 *
 * @param e Properties of the connecting edge to be removed.
 * @exception InstanceNotFound If the edge propertes are not registered to a
 *     connection of the graph.
 */
template <typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::removeEdge(
    GraphEdge& e, const GraphNode* tailNode, const GraphNode* headNode,
    BoostGraph* modifierGraph) {
    if (hasEdge(e, tailNode, headNode)) {
        boost::remove_edge(descriptor(e), graph_);
 
        typename EdgeDescMap::iterator
            edIter = edgeDescriptors_.find(&e);
        if (edIter != edgeDescriptors_.end()) {
            edgeDescriptors_.erase(edIter);
        }
 
        if (parentGraph_ != NULL && parentGraph_ != modifierGraph) {
            parentGraph_->removeEdge(e, tailNode, headNode, this);
        }
 
        for (unsigned int i = 0; i < childGraphs_.size(); i++) {
            if (childGraphs_.at(i) != modifierGraph ) {
                childGraphs_.at(i)->removeEdge(e, tailNode, headNode, this);
            }
        }
        delete pathCache_;
        pathCache_ = NULL;
    }
}
 
//////////////////////////////////////////////////////////////////////////////
// Subgraph related public methods
//////////////////////////////////////////////////////////////////////////////
 
/**
 * Returns the parent graph of this subgraph.
 * If the graph has no parent, returns NULL.
 *
 * @return parent graph of this subgraph or NULL if is not subgraph.
 */
template <typename GraphNode, typename GraphEdge>
BoostGraph<GraphNode, GraphEdge>*
BoostGraph<GraphNode, GraphEdge>::parentGraph() {
    return parentGraph_;
}
 
/**
 * Returns the root graph of this subgraph.
 * If this has no parent, return this.
 *
 * @return parent graph of this subgraph.
 */
template <typename GraphNode, typename GraphEdge>
BoostGraph<GraphNode, GraphEdge>*
BoostGraph<GraphNode, GraphEdge>::rootGraph() {
    if (parentGraph_ == NULL) {
        return this;
    }
    return parentGraph_;
}
 
/**
 * Returns the root graph of this subgraph.
 * If this has no parent, return this.
 *
 * @return parent graph of this subgraph.
 */
template <typename GraphNode, typename GraphEdge>
const BoostGraph<GraphNode, GraphEdge>*
BoostGraph<GraphNode, GraphEdge>::rootGraph() const {
    if (parentGraph_ == NULL) {
        return this;
    }
    return parentGraph_;
}
 
/**
 * Creates a subgraph from this graph.
 *
 * This procedure is suposed to be called from derived class's
 * createSubGraph method which also wold create the new object.
 */
template <typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::constructSubGraph(
    BoostGraph& subGraph, NodeSet& nodes) {
    // first add nodes
    for( typename NodeSet::iterator i = nodes.begin();
         i != nodes.end(); i++ ) {
        GraphNode& gn = *(*i);
        subGraph.addNode(gn);
    }
    // then edges
    for( typename NodeSet::iterator i = nodes.begin();
         i != nodes.end(); i++ ) {
        GraphNode& gn = *(*i);
        NodeDescriptor nd = descriptor(gn);
 
        std::pair<OutEdgeIter, OutEdgeIter> edges =
            boost::out_edges(nd, graph_);
        for (OutEdgeIter j = edges.first; j != edges.second; j++) {
            EdgeDescriptor ed = *j;
            NodeDescriptor hd = boost::target(ed, graph_);
            GraphNode* head = graph_[hd];
            if (nodes.find(head) != nodes.end()) {
                subGraph.connectNodes(gn, *head, *graph_[ed], NULL, true);
            }
        }
    }
    subGraph.parentGraph_ = this;
    childGraphs_.push_back(&subGraph);
    subGraph.name_ = name() + "_" + Conversion::toString(++sgCounter_);
}
 
/**
 * When a node has been dropped from a subgraph, this restores it,
 * based on the edges on the parent graph
 */
template <typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::restoreNodeFromParent(
    GraphNode& n) {
    assert(parentGraph_ != NULL);
 
    BoostGraph<GraphNode, GraphEdge>* parent = parentGraph_;
    parentGraph_ = NULL;
 
    addNode(n);
    NodeDescriptor ndp = parent->descriptor(n);
 
    std::pair<OutEdgeIter, OutEdgeIter> oEdges =
        boost::out_edges(ndp, parent->graph_);
 
    for (OutEdgeIter j = oEdges.first; j != oEdges.second; j++) {
        NodeDescriptor hd = boost::target(*j, parent->graph_);
        GraphNode* head = parent->graph_[hd];
        if (hasNode(*head)) {
            Edge& e = *graph_[*j];
            connectNodes(n, *head, e, NULL, true);
            calculatePathLengthsOnConnect(n, *head, e);
        }
    }
 
    std::pair<InEdgeIter, InEdgeIter> iEdges =
        boost::in_edges(ndp, parent->graph_);
 
    for (InEdgeIter j = iEdges.first; j != iEdges.second; j++) {
        NodeDescriptor tl = boost::source(*j, parent->graph_);
        GraphNode* tail = parent->graph_[tl];
        if (hasNode(*tail) && tail != &n) {
            Edge& e = *graph_[*j];
            connectNodes(*tail, n, e, NULL, true);
            calculatePathLengthsOnConnect(*tail, n, e);
        }
    }
    parentGraph_ = parent;
}
 
/*
 * Detach a subgraph from this graph.
 *
 * After this the subgraph is no longer updated when the graph is changed.
 * Does NOT remove parent_ of the subgraph, ie. leaves the subgraph in
 * non-functional stage. Should be used only just before deleting subgraph.
 *
 * @param subGraph subgraph to remove from the graph
 */
template <typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::detachSubgraph(BoostGraph& subGraph) {
    for (typename std::vector<BoostGraph<GraphNode, GraphEdge>*>::iterator
             iter = childGraphs_.begin(); iter != childGraphs_.end();iter++) {
        if ( *iter == &subGraph ) {
            childGraphs_.erase(iter);
            return;
        }
    }
}
 
 
/////////////////////////////////////////////////////////////////////////////
// Private helper methods
/////////////////////////////////////////////////////////////////////////////
 
/**
 *
 * Checks whether the given node belongs to the graph
 *
 * @param node node being tested
 * @return whether the ndoe belongs to the graph
 */
template <typename GraphNode, typename GraphEdge>
bool
BoostGraph<GraphNode, GraphEdge>::hasNode(const GraphNode& node) const {
 
    if (AssocTools::containsKey(nodeDescriptors_,&node)) {
        return true;
    }
 
    typedef std::pair<NodeIter, NodeIter> NodeIterPair;
    NodeIterPair nodes = boost::vertices(graph_);
    for (NodeIter i = nodes.first; i != nodes.second; i++) {
        if (graph_[*i] == &node) {
            nodeDescriptors_[&node] = *i;
            return true;
        }
    }
    return false;
}
 
/**
 *
 * Checks whether there exists and edge between the given nodes
 *
 * @param nTail tail node of the edge
 * @param nHead head node of the edge
 * @return whether there is an edge from nTail to nHead
 */
template <typename GraphNode, typename GraphEdge>
bool
BoostGraph<GraphNode, GraphEdge>::hasEdge(
    const GraphNode& nTail,
    const GraphNode& nHead) const {
 
    typedef std::pair<EdgeDescriptor, bool> EdgeReturned;
    EdgeReturned er = boost::edge(
        descriptor(nTail), descriptor(nHead), graph_);
    if (er.second == true) {
        return true;
    }
    return false;
}
 
/**
 *
 * Checks whether the given edge connects the given nodes
 *
 * @param nTail tail node of the edge
 * @param nHead head node of the edge
 * @param edge edge which may connect the nodes
 * @return whether the given edge does from nTail to nHead
 */
template <typename GraphNode, typename GraphEdge>
bool
BoostGraph<GraphNode, GraphEdge>::hasEdge(
    const GraphNode& nTail,
    const GraphNode& nHead,
    const GraphEdge& edge) const {
 
    typedef std::pair<OutEdgeIter, OutEdgeIter> OutEdgeIterPair;
 
    unsigned int hd = descriptor(nHead);
    OutEdgeIterPair edges = boost::out_edges(descriptor(nTail), graph_);
 
    for (OutEdgeIter i = edges.first; i != edges.second; i++) {
        if (graph_[*i] == &edge && target(*i, graph_) == hd) {
            return true;
        }
    }
    return false;
}
 
/**
 *
 * Checks whether the given edge belongs to the graph.
 *
 * @param edge edge being tested
 * @param tailnode, if known. makes this routine faster.
 * @param headnode, if known. makes this routine faster.
 * @return whether the edge belongs to the graph
 */
template <typename GraphNode, typename GraphEdge>
bool
BoostGraph<GraphNode, GraphEdge>::hasEdge(
    const GraphEdge& e,
    const GraphNode* nTail,
    const GraphNode* nHead) const {
 
    if (AssocTools::containsKey(edgeDescriptors_,&e)) {
        return true;
    }
 
    // if we have tails, check if's out edges
    if (nTail != NULL && hasNode(*nTail)) {
        typedef std::pair<OutEdgeIter, OutEdgeIter> OutEdgeIterPair;
 
        OutEdgeIterPair edges = boost::out_edges(descriptor(*nTail), graph_);
 
        for (OutEdgeIter i = edges.first; i != edges.second; i++) {
            if (graph_[*i] == &e) {
                edgeDescriptors_[&e] = *i;
                return true;
            }
        }
        return false;
    } else { // if we have head, check it's in edges.
        if (nHead != NULL && hasNode(*nHead)) {
            typedef std::pair<InEdgeIter, InEdgeIter> InEdgeIterPair;
 
            InEdgeIterPair edges = boost::in_edges(descriptor(*nHead), graph_);
 
            for (InEdgeIter i = edges.first; i != edges.second; i++) {
                if (graph_[*i] == &e) {
                    edgeDescriptors_[&e] = *i;
                    return true;
                }
            }
            return false;
        }
    }
 
    // we don't have head or tail, slowly go thru all edges.
    typedef std::pair<EdgeIter, EdgeIter> EdgeIterPair;
    EdgeIterPair edges = boost::edges(graph_);
 
    for (EdgeIter i = edges.first; i != edges.second; i++) {
        if (graph_[*i] == &e) {
            edgeDescriptors_[&e] = *i;
            return true;
        }
    }
    return false;
}
 
template <typename GraphNode, typename GraphEdge>
typename BoostGraph<GraphNode, GraphEdge>::EdgeDescriptor
BoostGraph<GraphNode, GraphEdge>::descriptor(const GraphEdge& e) const {
 
    typename EdgeDescMap::iterator cacheIter = edgeDescriptors_.find(&e);
    if (cacheIter != edgeDescriptors_.end()) {
        return cacheIter->second;
    }
 
    typedef std::pair<EdgeIter, EdgeIter> EdgeIterPair;
    EdgeIterPair edges = boost::edges(graph_);
 
    for (EdgeIter i = edges.first; i != edges.second; i++) {
        if (graph_[*i] == &e) {
            edgeDescriptors_[&e] = *i;
            return *i;
        }
    }
    assert(false && "Descriptor for edge not found!");
    return *edges.second;
}
 
template <typename GraphNode, typename GraphEdge>
typename BoostGraph<GraphNode, GraphEdge>::EdgeDescriptor
BoostGraph<GraphNode, GraphEdge>::edgeDescriptor(
    const GraphEdge& e, const NodeDescriptor& headNode) const {
 
    typename EdgeDescMap::iterator cacheIter = edgeDescriptors_.find(&e);
    if (cacheIter != edgeDescriptors_.end()) {
        return cacheIter->second;
    }
 
    typedef std::pair<InEdgeIter, InEdgeIter> EdgeIterPair;
    EdgeIterPair edges = boost::in_edges(headNode,graph_);
 
    for (InEdgeIter i = edges.first; i != edges.second; i++) {
        if (graph_[*i] == &e) {
            edgeDescriptors_[&e] = *i;
            return *i;
        }
    }
    assert(false);
    return *edges.second;
}
 
template <typename GraphNode, typename GraphEdge>
typename BoostGraph<GraphNode, GraphEdge>::EdgeDescriptor
BoostGraph<GraphNode, GraphEdge>::edgeDescriptor(
    const NodeDescriptor& tailNode, const GraphEdge& e) const {
 
    typename EdgeDescMap::iterator cacheIter = edgeDescriptors_.find(&e);
    if (cacheIter != edgeDescriptors_.end()) {
    return cacheIter->second;
    }
 
    typedef std::pair<OutEdgeIter, OutEdgeIter> EdgeIterPair;
    EdgeIterPair edges = boost::out_edges(tailNode,graph_);
 
    for (OutEdgeIter i = edges.first; i != edges.second; i++) {
        if (graph_[*i] == &e) {
            edgeDescriptors_[&e] = *i;
            return *i;
        }
    }
    assert(false);
    return *edges.second;
}
 
template <typename GraphNode, typename GraphEdge>
typename BoostGraph<GraphNode, GraphEdge>::NodeDescriptor
BoostGraph<GraphNode, GraphEdge>::descriptor(const GraphNode& n) const {
 
    typename NodeDescMap::iterator cacheIter = nodeDescriptors_.find(&n);
    if (cacheIter != nodeDescriptors_.end()) {
    return cacheIter->second;
    }
 
    typedef std::pair<NodeIter, NodeIter> NodeIterPair;
    NodeIterPair nodes = boost::vertices(graph_);
 
    for (NodeIter i = nodes.first; i != nodes.second; i++) {
        if (graph_[*i] == &n) {
            nodeDescriptors_[&n] = *i;
            return *i;
        }
    }
    Application::logStream() 
        << "Node " << n.toString() << "not in graph!" << std::endl;
    BoostGraph<GraphNode, GraphEdge>::writeToDotFile("missing_node.dot");
 
    assert(false);
    return *nodes.second;
}
 
 
template <typename GraphNode, typename GraphEdge>
typename BoostGraph<GraphNode, GraphEdge>::EdgeDescriptor
BoostGraph<GraphNode, GraphEdge>::connectingEdge(
    const GraphNode& nTail,
    const GraphNode& nHead) const {
 
    typedef std::pair<EdgeDescriptor, bool> EdgeReturned;
 
    EdgeReturned edges = boost::edge(
        descriptor(nTail), descriptor(nHead), graph_);
    if (edges.second == false) {
        abortWithError("Connecting edge not found!");
    }
    return edges.first;
}
 
/**
 * Returns all the root nodes of the graph.
 *
 * Root nodes are nodes of which input degree is 0 (no edges entering, only
 * leaving). Also known as 'source nodes'.
 *
 * @return Set of root nodes, can be empty.
 */
template<typename GraphNode, typename GraphEdge>
typename BoostGraph<GraphNode, GraphEdge>::NodeSet
BoostGraph<GraphNode, GraphEdge>::rootNodes() const {
 
    NodeSet rootNodes;
    for (int nodeIndex = 0; nodeIndex < nodeCount(); ++nodeIndex) {
        GraphNode& nod = node(nodeIndex);
        if (inDegree(nod) == 0)
            rootNodes.insert(&nod);
    }
    return rootNodes;
}
 
 
/**
 * Returns all the sink nodes of the graph.
 *
 * Sink nodes are nodes of which output degree is 0 (no edges exiting, only
 * incoming).
 *
 * @return Set of sink nodes, can be empty.
 */
template<typename GraphNode, typename GraphEdge>
typename BoostGraph<GraphNode, GraphEdge>::NodeSet
BoostGraph<GraphNode, GraphEdge>::sinkNodes() const {
 
    NodeSet sinkNodes;
    for (int nodeIndex = 0; nodeIndex < nodeCount(); ++nodeIndex) {
        GraphNode& nod = node(nodeIndex);
        if (outDegree(nod) == 0)
            sinkNodes.insert(&nod);
    }
    return sinkNodes;
}
 
/**
 * Returns all the successors of the given node.
 *
 * If node has no successors, an empty set is returned. Note: the node can
 * also be a successor of itself.
 *
 * @param node The node of which successors to find.
 * @return Set of root nodes, can be empty.
 */
template<typename GraphNode, typename GraphEdge>
typename BoostGraph<GraphNode, GraphEdge>::NodeSet
BoostGraph<GraphNode, GraphEdge>::successors(
    const Node& node, bool ignoreBackEdges, bool ignoreForwardEdges) const {
 
    NodeSet succ;
 
    NodeDescriptor nd = descriptor(node);
    typedef typename GraphTraits::out_edge_iterator outEdgeIter;
    std::pair<outEdgeIter, outEdgeIter> edges = boost::out_edges(nd, graph_);
 
    for (outEdgeIter ei = edges.first; ei != edges.second; ei++) {
        EdgeDescriptor ed = *ei;
        GraphEdge* edge = graph_[ed];
        bool backEdge = edge->isBackEdge();
        if (!((ignoreBackEdges && backEdge) ||
              (ignoreForwardEdges && !backEdge))) {
            NodeDescriptor ndHead = boost::target(ed, graph_);
            GraphNode* head = graph_[ndHead];
            succ.insert(head);
        }
    }
 
    return succ;
}
 
/**
 * Returns all the predecessors of the given node.
 *
 * If node has no predecessors, an empty set is returned. Note: the node can
 * also be a predecessor of itself.
 *
 * @param node The node of which predecessors to find.
 * @return Set of root nodes, can be empty.
 */
template<typename GraphNode, typename GraphEdge>
typename BoostGraph<GraphNode, GraphEdge>::NodeSet
BoostGraph<GraphNode, GraphEdge>::predecessors(
    const Node& node, bool ignoreBackEdges, bool ignoreForwardEdges) const {
 
    NodeSet pred;
 
    typedef typename GraphTraits::in_edge_iterator InEdgeIter;
    std::pair<InEdgeIter, InEdgeIter> edges = boost::in_edges(
        descriptor(node), graph_);
 
    for (InEdgeIter ei = edges.first; ei != edges.second; ++ei) {
        EdgeDescriptor ed = *ei;
        GraphEdge* edge = graph_[ed];
        bool backEdge = edge->isBackEdge();
        if (!((ignoreBackEdges && backEdge) ||
              (ignoreForwardEdges && !backEdge))) {
            NodeDescriptor nTail = boost::source(ed, graph_);
            GraphNode* tail = graph_[nTail];
            pred.insert(tail);
        }
    }
    return pred;
}
 
/**
 * Calculates maximum path lengths from sinks and sources to all nodes.
 *
 * This procedure is called internally when this information is needed
 */
template<typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::calculatePathLengthsFast() const {
    std::vector<NodeDescriptor> sortedNodes;
    sortedNodes.reserve(nodeCount());
    // inserts first elements into end?
    topological_sort(graph_, std::back_inserter(sortedNodes));
    for (unsigned int i = 0 ; i < sortedNodes.size(); i++) {
        NodeDescriptor& nd = sortedNodes[i];
        const Node* node = graph_[nd];
        int len = sinkDistances_[node];
 
        // loop over all in edges.
        std::pair <InEdgeIter, InEdgeIter> edges = boost::in_edges(nd, graph_);
        for (InEdgeIter ii = edges.first; ii != edges.second; ii++) {
            EdgeDescriptor ed = *ii;
            Edge* edge = graph_[ed];
            NodeDescriptor td = boost::source(*ii, graph_);
            const Node* tailNode = graph_[td];
            int eWeight = edgeWeight(*edge, *node);
            int sdLen = len + eWeight;
            
            // find the place in the sourcedistances table
            auto sdIter = sinkDistances_.find(tailNode);
            // update if this path is longer.
            if (sdIter == sinkDistances_.end()) {
                sinkDistances_[tailNode] = sdLen;
                if (sdLen > height_) {
                    height_ = sdLen;
                }
            } else if(sdIter->second < sdLen) {
                sdIter->second = sdLen;
                if (sdLen > height_) {
                    height_ = sdLen;
                }
            }
        }
    }
}
 
/**
 * Calculates maximum path lengths from sinks and sources to all nodes.
 *
 * This procedure is called internally when this information is needed
 */
template<typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::calculatePathLengths() const {
 
    calculateSourceDistances();
 
    if (!allowLoopEdges_) {
        calculatePathLengthsFast();
        return;
    } 
 
    // priority queue of all sink nodes.
    std::priority_queue<PathLengthHelper> sinkDistanceQueue;
 
    // insert all sink nodes to the pqueue
    for (int i = nodeCount() -1 ; i >= 0 ; i--) {
 
        NodeDescriptor nd = descriptor(node(i));
        std::pair <OutEdgeIter, OutEdgeIter> edges = boost::out_edges(
            nd, graph_);
 
        bool outEdgeFound = false;
        for (OutEdgeIter ii = edges.first; ii != edges.second;
             ii++) {
            EdgeDescriptor ed = *ii;
            if (!graph_[ed]->isBackEdge()) {
                outEdgeFound = true;
            }
        }
        if (!outEdgeFound) {
            sinkDistanceQueue.push(
                PathLengthHelper(nd, 0, sourceDistances_[&node(i)]));
        }
    }
 
    // and then start sink calculation from each of them.
    while (!sinkDistanceQueue.empty()) {
        calculateSinkDistance(*graph_[sinkDistanceQueue.top().nd_],0);
        sinkDistanceQueue.pop();
    }
}
 
/**
 * Calculates source distances of nodes.
 *
 * Iterative algorithm, starts from given node or all source nodes.
 *
 * Does a breadth-first search, prioritizating first nodes in the graph.
 *
 * @param startingNode node whose successors's source dist to calculate,
 * or NULL if start from all sources.
 *
 * @param startingLength source distance of the startingnode.
 */
template<typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::calculateSourceDistances(
    const GraphNode* startingNode, int startingLength, bool looping) const {
 
    if (startingLength > height_) {
        height_ = startingLength;
    }
 
    // priority queue of nodes to be processed
    typename std::map <NodeDescriptor, int> sourceDistanceQueue;
 
    // priority queue of nodes to be processed
    typename std::map <NodeDescriptor, int> loopingSourceDistanceQueue;
 
    // first initialize starting nodes to the queue
 
    // one starting node?
    if (startingNode != NULL) {
        if (!looping) {
            sourceDistances_[startingNode] = startingLength;
            sourceDistanceQueue[descriptor(*startingNode)] = startingLength;
        } else {
            loopingSourceDistances_[startingNode] = startingLength;
            loopingSourceDistanceQueue[descriptor(*startingNode)] =
                startingLength;
        }
 
    } else {
        // insert all source nodes to the pqueue
        for (int i = 0; i < nodeCount(); i++) {
            NodeDescriptor nd = boost::vertex(i, graph_);
            std::pair <InEdgeIter, InEdgeIter> edges = boost::in_edges(
                nd, graph_);
 
            bool inEdgeFound = false;
            for (InEdgeIter ii = edges.first; ii != edges.second;
                 ii++) {
                EdgeDescriptor ed = *ii;
                if (!graph_[ed]->isBackEdge()) {
                    inEdgeFound = true;
                }
            }
            if (!inEdgeFound) {
                sourceDistances_[graph_[nd]] = startingLength;
                sourceDistanceQueue[nd] = startingLength;
            }
        }
    }
 
    // and then start sink calculation from each of them.
    while (!sourceDistanceQueue.empty()) {
        typename std::map <NodeDescriptor, int>::iterator sdBegin =
            sourceDistanceQueue.begin();
 
        NodeDescriptor nd = sdBegin->first;
        int len = sdBegin->second;
        sourceDistanceQueue.erase(sdBegin);
 
        // then test all successors..
        std::pair <OutEdgeIter, OutEdgeIter> edges = boost::out_edges(
            nd, graph_);
        for (OutEdgeIter oi = edges.first; oi != edges.second; oi++) {
            EdgeDescriptor ed = *oi;
            GraphEdge *edge = graph_[ed];
            NodeDescriptor headDesc = boost::target(ed, graph_);
            Node* headNode = graph_[headDesc];
            int eWeight = edgeWeight(*edge, *headNode);
            int destLen = len + eWeight;
 
            if (destLen > height_) {
                height_ = destLen;
            }
 
            // normal or loop-containing length?
            auto & sourceDistances =
                edge->isBackEdge() ? loopingSourceDistances_:sourceDistances_;
 
            // find the place in the sourcedistances table
            auto sdIter = sourceDistances.find(headNode);
 
            // if not yet there, add
            if (sdIter == sourceDistances.end()) {
                sourceDistances[headNode] = destLen;
            } else {
                // this is longer? replace with this
                if (sdIter->second < destLen ) {
                    sdIter->second = destLen;
                } else {
                    // we have already been here, with bigger path.
                    // no need to check successors.
                    continue;
                }
            }
 
            // add to normal or loop-containing queue?
            typename std::map<
                NodeDescriptor,int> &
                mySourceDistanceQueue =
                edge->isBackEdge() ?
                loopingSourceDistanceQueue : sourceDistanceQueue;
 
            // then may enqueue the successor for processing it.
            typename std::map <NodeDescriptor, int>::iterator qiter =
                mySourceDistanceQueue.find(headDesc);
            if (qiter == mySourceDistanceQueue.end()) {
                // not found from queue, add it there.
                mySourceDistanceQueue[headDesc] = destLen;
            } else {
                // already is in queue.
                if (qiter->second < destLen) {
                    // if this one has longer path, replace the queued
                    // ath lenght with this path length.
                    qiter->second = destLen;
                }
            }
        }
    }
 
    // then iterate over nodes that have one loop node pointing to them.
    // do not follow any other loop edges.
 
    while (!loopingSourceDistanceQueue.empty()) {
        typename std::map <NodeDescriptor, int>::iterator sdBegin =
            loopingSourceDistanceQueue.begin();
 
        NodeDescriptor nd = sdBegin->first;
        int len = sdBegin->second;
        loopingSourceDistanceQueue.erase(sdBegin);
 
        // then test all successors..
        std::pair <OutEdgeIter, OutEdgeIter> edges = boost::out_edges(
            nd, graph_);
        for (OutEdgeIter oi = edges.first; oi != edges.second; oi++) {
            EdgeDescriptor ed = *oi;
            GraphEdge *edge = graph_[ed];
            // do not follow no more loop edges.
            if (edge->isBackEdge()) {
                continue;
            }
            NodeDescriptor headDesc = boost::target(ed, graph_);
            Node* headNode = graph_[headDesc];
            int eWeight = edgeWeight(*edge, *headNode);
            int destLen = len + eWeight;
 
            // find the place in the sourcedistances table
            auto sdIter = loopingSourceDistances_.find(headNode);
 
            // if not yet there, add
            if (sdIter == loopingSourceDistances_.end()) {
                loopingSourceDistances_[headNode] = destLen;
            } else {
                // this is longer? replace with this
                if (sdIter->second < destLen ) {
                    sdIter->second  = destLen;
                } else {
                    // we have already been here, with bigger path.
                    // no need to check successors.
                    continue;
                }
            }
 
            // then may enqueue the successor for processing it.
            typename std::map <NodeDescriptor, int>::iterator qiter =
                loopingSourceDistanceQueue.find(headDesc);
            if (qiter == loopingSourceDistanceQueue.end()) {
                // not found from queue, add it there.
                loopingSourceDistanceQueue[headDesc] = destLen;
            } else {
                // already is in queue.
                if (qiter->second < destLen) {
                    // if this one has longer path, replace the queued
                    // ath lenght with this path length.
                    qiter->second = destLen;
                }
            }
        }
    }
}
 
/**
 * Recursively calculates path lenght from sinks to sources.
 *
 * @param node Node curently being processed
 * @param len Current lenght from sink.
 */
template<typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::calculateSinkDistance(
    const Node& node, int len, bool looping ) const {
    if (len > 26000) {
        GraphBase<GraphNode,GraphEdge>::writeToDotFile("not_dag.dot");
        assert(false&&"cannot calc sink distance for graph which is not dag");
    }
 
    auto &sinkDistances = looping ? loopingSinkDistances_ : sinkDistances_;
 
    // find the place in the sourcedistances table
    auto sdIter = sinkDistances.find(&node);
 
    // if not yet there, add
    if (sdIter == sinkDistances.end()) {
        sinkDistances[&node] = len;
    } else {
        // this is longer? replace with this
        if (sdIter->second <= len ) {
            sdIter->second = len;
        } else {
            // we have already been here, with bigger path.
            // no need to check successors.
            return;
        }
    }
 
    if (len > height_) {
        height_ = len;
    }
 
    // priority queue of predecessor nodes. recurse always
    // to one with highest source distance
    std::priority_queue<PathLengthHelper> predecessorQueue;
    NodeDescriptor nd = descriptor(node);
    std::pair <InEdgeIter, InEdgeIter> edges = boost::in_edges(nd, graph_);
    for (InEdgeIter ii = edges.first; ii != edges.second; ii++) {
        EdgeDescriptor ed = *ii;
        Edge* edge = graph_[ed];
        // if already looping, may not be backedge.
        if (!looping || !edge->isBackEdge()) {
            NodeDescriptor td = boost::source(*ii, graph_);
            Node* tailNode = graph_[td];
            int eWeight = edgeWeight(*edge, node);
            int sdLen = len + eWeight;
            if (sdLen > height_) {
                height_ = sdLen;
            }
 
            // the predecessor is thru one loop?
            if (looping || edge->isBackEdge()) {
                sdIter = loopingSinkDistances_.find(tailNode);
                // if not yet there, add
                if (sdIter == loopingSinkDistances_.end()) {
                    loopingSinkDistances_[tailNode] = sdLen;
                } else {
                    // this is longer? replace with this
                    if (sdIter->second < sdLen) {
                        sdIter->second = sdLen;
                    } else {
                        // we have already been here, with bigger path.
                        // no need to check successors.
                        continue;
                    }
                }
                predecessorQueue.push(
                    PathLengthHelper(
                        td, sdLen, sourceDistances_[tailNode], true));
            } else {
                sdIter = sinkDistances_.find(tailNode);
                // if not yet there, add
                if (sdIter == sinkDistances_.end()) {
                    sinkDistances_[tailNode] = sdLen;
                } else {
                    // this is longer? replace with this
                    if (sdIter->second < sdLen ) {
                        sdIter->second = sdLen;
                    } else {
                        // we have already been here, with bigger path.
                        // no need to check successors.
                        continue;
                    }
                }
                predecessorQueue.push(
                    PathLengthHelper(
                        td, sdLen, sourceDistances_[tailNode], false));
            }
        }
    }
 
    // all predecessors are in the queue, loop it thru in
    // correct order.
    while (!predecessorQueue.empty()) {
 
        PathLengthHelper plh = predecessorQueue.top();
        calculateSinkDistance(
            *graph_[plh.nd_], plh.len_, plh.looping_);
        predecessorQueue.pop();
    }
}
 
/**
 * Gives the lenght of a longest path a node belongs in a graph.
 *
 * If the path lenghts are not calculated calculates them.
 * If the graph is a cyclic graph, the function may never return.
 *
 * @param node Node belonging to a path.
 *
 * @return length of the longest path where given node belongs to
 */
template<typename GraphNode, typename GraphEdge>
int
BoostGraph<GraphNode, GraphEdge>::maxPathLength(const GraphNode& node) const {
    return maxSinkDistance(node) + maxSourceDistance(node);
}
 
/**
 * Gives the lenght of a longest path from any source node to given node.
 *
 * If the path lenghts are not calculated calculates them.
 * If the graph is a cyclic graph without back edges correctly set,
 * the function may never return. If all cycles contain at least one
 * backedge, this should work, and it will then return longest path where
 * maximum of one loop is looped.
 *
 * @param node Node belonging to a path.
 *
 * @return length of the longest path where given node belongs to
 */
template<typename GraphNode, typename GraphEdge>
int
BoostGraph<GraphNode, GraphEdge>::maxSourceDistance(const GraphNode& node)
    const {
 
    if (!hasNode(node)) {
        return -1;
    }
 
 
    for (int i = 0; i < 2; i++) {
        auto iter = loopingSourceDistances_.find(&node);
        if (iter != loopingSourceDistances_.end()) {
            return iter->second;
        }
 
        auto iter2 = sourceDistances_.find(&node);
 
        if (iter2 == sourceDistances_.end()) {
            if (i == 0) {
                calculateSourceDistances();
            }
        } else {
            return iter2->second;
        }
    }
    if (!hasNode(node)) {
        return -1;
    }
    std::cerr << "Node lacks source distance! " << node.nodeID() << " " << node.nodeID() << " "
              << node.toString() << std::endl;
    BoostGraph<GraphNode, GraphEdge>::writeToDotFile("lacking_sourced.dot");
    assert(0 && "source distance should have been found.");
    return -1;
}
 
/**
 * Gives the lenght of a longest path from the given node to any sink node.
 *
 * If the path lenghts are not calculated calculates them.
 * If the graph is a cyclic graph without back edges correctly set,
 * the function may never return. If all cycles contain at least one
 * backedge, this should work, and it will then return longest path where
 * maximum of one loop is looped.
 *
 * @param node Node belonging to a path.
 *
 * @return length of the longest path where given node belongs to
 */
template<typename GraphNode, typename GraphEdge>
int
BoostGraph<GraphNode, GraphEdge>::maxSinkDistance(const GraphNode& node)
    const {
 
    if (!hasNode(node)) {
        return -1;
    }
 
    for (int i = 0; i < 2; i++) {
        auto iter = loopingSinkDistances_.find(&node);
        if (iter != loopingSinkDistances_.end()) {
            if (sinkDistances_.find(&node) == sinkDistances_.end() ||
                iter->second > sinkDistances_[&node]) {
                return iter->second;
            }
        }
 
        auto iter2 = sinkDistances_.find(&node);
 
        if (iter2 == sinkDistances_.end()) {
            calculatePathLengths();
        } else {
            return iter2->second;
        }
    }
    if (!hasNode(node)) {
        return -1;
    }
    std::cerr << "Node lacks sink distance! " << node.nodeID() << " "
              << node.toString() << std::endl;
    BoostGraph<GraphNode, GraphEdge>::writeToDotFile("lacking_sinkd.dot");
 
    assert(0 && "sink distance should have been found.");
    return -1;
}
 
/**
 * Gives the longest path in acyclic graph.
 *
 * If the path lenghts are not calculated calculates them.
 * If the graph is a cyclic graph, the function may never return.
 *
 * @return Longst path in acyclic graph.
 */
template<typename GraphNode, typename GraphEdge>
int
BoostGraph<GraphNode, GraphEdge>::height() const {
 
    if (height_ == -1) {
        calculatePathLengths();
    }
 
    return height_;
}
 
/**
 * Gives weight of a one edge in a graph.
 *
 * Derived class should overrider this with real implementation
 * which does the actual node weight calculation.
 *
 * This base class implementation always returns 1.
 *
 * @return The weight of an edge.
 */
template <typename GraphNode, typename GraphEdge>
int
BoostGraph<GraphNode, GraphEdge>::edgeWeight(
    GraphEdge&,const GraphNode&) const {
    return 1;
}
 
/**
 * Returns all edges that connect two nodes.
 *
 * @param nTail source node
 * @param nHead destination node
 * @return a set containing all edges from nTail to nHead
 */
template <typename GraphNode, typename GraphEdge>
typename BoostGraph<GraphNode, GraphEdge>::EdgeSet
BoostGraph<GraphNode, GraphEdge>::connectingEdges(
    const GraphNode& nTail, const GraphNode& nHead) const {
 
    EdgeSet headIn = inEdges(nHead);
    EdgeSet tailOut = outEdges(nTail);
    EdgeSet intersection;
    SetTools::intersection(headIn, tailOut, intersection);
    return intersection;
}
 
template <typename GraphNode, typename GraphEdge>
const TCEString&
BoostGraph<GraphNode, GraphEdge>::name() const {
    return name_;
}
 
/**
 * Finds all paths between nodes and updates the internal path cache.
 *
 * This data is used internally to speed up hasPath(). 
 */
template <typename GraphNode, typename GraphEdge>
void
BoostGraph<GraphNode, GraphEdge>::findAllPaths() const {
    
    using namespace boost;    
 
    typedef std::map<EdgeDescriptor, int> WeightMap;
    WeightMap weightsMap;
    associative_property_map<WeightMap> weights(weightsMap);
 
    typedef std::pair<EdgeIter, EdgeIter> EdgeIterPair;
    EdgeIterPair edges = boost::edges(graph_);
    for (EdgeIter i = edges.first; i != edges.second; i++) {
        weightsMap[*i] = 0;
    }
 
    const int nodes = nodeCount();
    delete pathCache_;
    pathCache_ = new PathCache;
    for (int i = 0; i < nodes; ++i) {
        pathCache_->push_back(std::vector<int>(nodes));
    }
    johnson_all_pairs_shortest_paths(graph_, *pathCache_, weight_map(weights));
}
 
template <typename GraphNode, typename GraphEdge>
bool
BoostGraph<GraphNode, GraphEdge>::hasPath(
    GraphNode& src, const GraphNode& dest) const {
 
    if (&src == &dest) {
        return true;
    }
 
    if (pathCache_ != NULL) {
        return (*pathCache_)[descriptor(src)][descriptor(dest)] !=
            (std::numeric_limits<int>::max)();
    }
    NodeSet foundNodes;
    NodeSet queue;
    queue.insert(&src);
    int dstSinkDist = -1;
    if (height_ != -1) {
        dstSinkDist = maxSinkDistance(dest);
    }
    while (!queue.empty()) {
        GraphNode* current = *queue.begin();
        queue.erase(current);
 
        int sd = INT_MAX;
        if (height_ != -1) {
            sd = maxSinkDistance(*current);
        }
        if (sd >= dstSinkDist) {
            NodeDescriptor nd = descriptor(*current);
            std::pair<OutEdgeIter, OutEdgeIter> edges =
                boost::out_edges(nd, graph_);
            for (OutEdgeIter ei = edges.first; ei != edges.second; ei++) {
                EdgeDescriptor ed = *ei;
                const Edge& edge = *graph_[ed];
                if (edge.isBackEdge()) {
                    continue;
                }
                NodeDescriptor hd = boost::target(ed, graph_);
                Node* const head = graph_[hd];
 
                if (head == &dest) {
                    return true;
                }
                if (foundNodes.find(head) == foundNodes.end()) {
                    queue.insert(head);
                    foundNodes.insert(head);
                    // make sure found from the descriptor cache.
                    nodeDescriptors_[head] = hd;
                }
            }
        }
    }
    return false;
}
 
/**
 * Detects cycles that happen without proper backedge properties
 * This routine is currently quite slow , there is room for
 * optimization. This is to be used for debugging.
 */
template <typename GraphNode, typename GraphEdge>
bool
BoostGraph<GraphNode, GraphEdge>::detectIllegalCycles() const {
    for (int i = 0; i < nodeCount(); i++) {
        GraphNode* originalNode = &node(i);
        NodeSet queuedNodes;
        NodeSet foundNodes;
        queuedNodes.insert(originalNode);
        foundNodes.insert(originalNode);
        while (!queuedNodes.empty()) {
            const GraphNode* n = *queuedNodes.begin();
            queuedNodes.erase(queuedNodes.begin());
            EdgeSet es = outEdges(*n);
            for (typename EdgeSet::iterator ei = es.begin(); ei != es.end(); ei++) {
                const GraphEdge* e = *ei;
                if (!e->isBackEdge()) {
                    GraphNode& head = headNode(*e);
                    if (&head == originalNode) {
                        std::cerr << "Detected illegal cycle between nodes: "
                                  << originalNode->toString() << " and "
                                  << n->toString() << " edge: " <<
                            e->toString() << std::endl;
                        return true;
                    }
                    if (!AssocTools::containsKey(foundNodes,&head)) {
                        foundNodes.insert(&head);
                        queuedNodes.insert(&head);
                    }
                }
            }
        }
    }
    return false;
}
 
template <typename GraphNode, typename GraphEdge>
bool
BoostGraph<GraphNode, GraphEdge>::PathLengthHelper::operator<(
    const BoostGraph<GraphNode, GraphEdge>::PathLengthHelper& other) const {
    return sd_ < other.sd_;
}
 
template <typename GraphNode, typename GraphEdge>
BoostGraph<GraphNode, GraphEdge>::PathLengthHelper::PathLengthHelper(
    typename BoostGraph<GraphNode,GraphEdge>::NodeDescriptor nd,
    int len, int sd, bool looping) :
    nd_(nd), len_(len), sd_(sd), looping_(looping) {}