/** Finds shortcuts, does not change the underlying graph. */
void findShortcuts(ShortcutHandler sch) {
long tmpDegreeCounter = 0;
EdgeIterator incomingEdges = vehicleInExplorer.setBaseNode(sch.getNode());
// collect outgoing nodes (goal-nodes) only once
while (incomingEdges.next()) {
int u_fromNode = incomingEdges.getAdjNode();
// accept only uncontracted nodes
if (g.getLevel(u_fromNode) != 0) continue;
double v_u_weight = incomingEdges.getDistance();
int skippedEdge1 = incomingEdges.getEdge();
int incomingEdgeOrigCount = getOrigEdgeCount(skippedEdge1);
// collect outgoing nodes (goal-nodes) only once
EdgeIterator outgoingEdges = vehicleOutExplorer.setBaseNode(sch.getNode());
// force fresh maps etc as this cannot be determined by from node alone (e.g. same from node
// but different avoidNode)
algo.clear();
tmpDegreeCounter++;
while (outgoingEdges.next()) {
int w_toNode = outgoingEdges.getAdjNode();
// add only uncontracted nodes
if (g.getLevel(w_toNode) != 0 || u_fromNode == w_toNode) {
continue;
}
// Limit weight as ferries or forbidden edges can increase local search too much.
// If we decrease the correct weight we only explore less and introduce more shortcuts.
// I.e. no change to accuracy is made.
double existingDirectWeight = v_u_weight + outgoingEdges.getDistance();
algo.setLimitWeight(existingDirectWeight)
.setLimitVisitedNodes((int) meanDegree * 100)
.setEdgeFilter(levelEdgeFilter.setAvoidNode(sch.getNode()));
dijkstraSW.start();
dijkstraCount++;
int endNode = algo.findEndNode(u_fromNode, w_toNode);
dijkstraSW.stop();
// compare end node as the limit could force dijkstra to finish earlier
if (endNode == w_toNode && algo.getWeight(endNode) <= existingDirectWeight)
// FOUND witness path, so do not add shortcut
continue;
sch.foundShortcut(
u_fromNode,
w_toNode,
existingDirectWeight,
outgoingEdges,
skippedEdge1,
incomingEdgeOrigCount);
}
}
if (sch instanceof AddShortcutHandler) {
// sliding mean value when using "*2" => slower changes
meanDegree = (meanDegree * 2 + tmpDegreeCounter) / 3;
// meanDegree = (meanDegree + tmpDegreeCounter) / 2;
}
}
