/**
* Simple single-function interface to split and then update a graph
*
* @param graph the graph containing the vertices in toMerge
* @param v The bottom node whose incoming vertices we'd like to split
* @return true if some useful splitting was done, false otherwise
*/
public boolean split(final SeqGraph graph, final SeqVertex v) {
if (graph == null) throw new IllegalArgumentException("graph cannot be null");
if (v == null) throw new IllegalArgumentException("v cannot be null");
if (!graph.vertexSet().contains(v))
throw new IllegalArgumentException("graph doesn't contain vertex v " + v);
final Collection<SeqVertex> toSplit = graph.incomingVerticesOf(v);
if (toSplit.size() < 2)
// Can only split at least 2 vertices
return false;
else if (!safeToSplit(graph, v, toSplit)) {
return false;
} else {
final SeqVertex suffixVTemplate = commonSuffix(toSplit);
if (suffixVTemplate.isEmpty()) {
return false;
} else if (wouldEliminateRefSource(graph, suffixVTemplate, toSplit)) {
return false;
} else if (allVerticesAreTheCommonSuffix(suffixVTemplate, toSplit)) {
return false;
} else {
final List<BaseEdge> edgesToRemove = new LinkedList<BaseEdge>();
// graph.printGraph(new File("split.pre_" + v.getSequenceString() + "." +
// counter + ".dot"), 0);
for (final SeqVertex mid : toSplit) {
// create my own copy of the suffix
final SeqVertex suffixV = new SeqVertex(suffixVTemplate.getSequence());
graph.addVertex(suffixV);
final SeqVertex prefixV = mid.withoutSuffix(suffixV.getSequence());
final BaseEdge out = graph.outgoingEdgeOf(mid);
final SeqVertex incomingTarget;
if (prefixV == null) {
// this node is entirely explained by suffix
incomingTarget = suffixV;
} else {
incomingTarget = prefixV;
graph.addVertex(prefixV);
graph.addEdge(prefixV, suffixV, new BaseEdge(out.isRef(), 1));
edgesToRemove.add(out);
}
graph.addEdge(suffixV, graph.getEdgeTarget(out), out.copy());
for (final BaseEdge in : graph.incomingEdgesOf(mid)) {
graph.addEdge(graph.getEdgeSource(in), incomingTarget, in.copy());
edgesToRemove.add(in);
}
}
graph.removeAllVertices(toSplit);
graph.removeAllEdges(edgesToRemove);
// graph.printGraph(new File("split.post_" + v.getSequenceString() + "." +
// counter++ + ".dot"), 0);
return true;
}
}
}
