/** Creates or gets to_from_path_map. */
private Map<Node, Set<Node>> getToFromPathMap(Node node) {
if (!node.hasLabel(TO_FROM_PATH_MAP)) {
node.putLabel(TO_FROM_PATH_MAP, new HashMap<Node, Set<Node>>());
}
return (Map<Node, Set<Node>>) node.getLabel(TO_FROM_PATH_MAP);
}
/**
* Finds the length of the shortest path between nodes from-to. This uses the labels on nodes
* which was previously introduced in MarkDistances algorithm.
*/
private int getShortestDistance(Node from, Node to) {
Map<Node, Integer> distTo = (Map<Node, Integer>) from.getLabel(MarkDistances.DIST_TO);
int s = Integer.MAX_VALUE;
if (distTo.containsKey(to)) {
s = distTo.get(to);
}
return s;
}
/**
* Make sure that distances are marked on the graph before running this.
*
* <p>For each node, this code checks any combination of from-to distance pairs. If the node is on
* a shortest+k path between from-to, then the to_from_path_map is used to mark this.
*/
public void run() {
for (Node node : graph.getNodes()) {
Map<Node, Integer> distFrom = (Map<Node, Integer>) node.getLabel(MarkDistances.DIST_FROM);
Map<Node, Integer> distTo = (Map<Node, Integer>) node.getLabel(MarkDistances.DIST_TO);
// Ignore nodes that are not in the middle of something
if (distFrom == null || distTo == null) {
continue;
}
// for each from-to pairs check if this node is on a shortest+k path
for (Node from : distFrom.keySet()) {
assert from.hasSignificantExperimentalChange(ExperimentData.EXPRESSION_DATA);
// We do not want to mark this node as on its shortest path
// if (from == node)
// {
// continue;
// }
for (Node to : distTo.keySet()) {
// We do not want to mark this node as on its shortest path
// if (to == node)
// {
// continue;
// }
if (from == node) {
continue;
}
int s = getShortestDistance(from, to);
if (s <= limit) {
// If shortest+k is higher than limit, then use limit
int d = Math.min(s + k, limit);
// If the length of the path from-to that contains this node
// is within limits, mark it.
int foundDistance = distFrom.get(from) + distTo.get(to);
if (!node.isBreadthNode()) {
foundDistance++;
}
if (foundDistance <= d) {
Map<Node, Set<Node>> tofromPathMap = getToFromPathMap(node);
if (!tofromPathMap.containsKey(to)) {
tofromPathMap.put(to, new HashSet<Node>());
}
Set<Node> fromSet = tofromPathMap.get(to);
fromSet.add(from);
// So, during a backwards traversing, starting at "to", when we visit
// this node, then we will know where to go.
}
}
}
}
}
}
