/**
* The remote vertex is scheduled for activation unless it has already been visited.
*
* <p>Note: We are scattering to out-edges. Therefore, this vertex is {@link
* Statement#getSubject()}. The remote vertex is {@link Statement#getObject()}.
*/
@Override
public void scatter(
final IGASState<PATHS.VS, PATHS.ES, Void> state,
final IGASScheduler sch,
final Value u,
final Statement e) {
// remote vertex state.
final Value v = state.getOtherVertex(u, e);
final VS otherState = state.getState(v);
final int otherDepth = otherState.depth();
// final VS otherState = state.getState(e.getObject()/* v */);
// visit.
if (otherState.visit(state.round() + 1, u /* predecessor */, e.getPredicate())) {
/*
* This is the first visit for the remote vertex. Add it to the
* schedule for the next iteration.
*/
sch.schedule(v);
}
}
/*
* TODO Do this in parallel for each specified target vertex.
*/
@Override
public void prunePaths(final IGASContext<VS, ES, Void> ctx, final Value[] targetVertices) {
// if(true)
// return;
if (ctx == null) throw new IllegalArgumentException();
if (targetVertices == null) throw new IllegalArgumentException();
final IGASState<PATHS.VS, PATHS.ES, Void> gasState = ctx.getGASState();
final Set<Value> retainSet = new HashSet<Value>();
for (Value v : targetVertices) {
if (!gasState.isVisited(v)) {
// This target was not reachable.
continue;
}
/*
* Walk the precessors back to a starting vertex.
*/
retainSet.add(v);
visitPredecessors(gasState, v, retainSet);
} // next target vertex.
gasState.retainAll(retainSet);
}
/** Not used. */
@Override
public void initVertex(
final IGASContext<PATHS.VS, PATHS.ES, Void> ctx,
final IGASState<PATHS.VS, PATHS.ES, Void> state,
final Value u) {
state.getState(u).visit(0, null /* predecessor */, null /* edge */);
}
protected void visitPredecessors(
final IGASState<PATHS.VS, PATHS.ES, Void> gasState,
final Value v,
final Set<Value> retainSet) {
final PATHS.VS currentState = gasState.getState(v);
// final int curDepth = currentState.depth.get();
for (Value pred : currentState.predecessors().keySet()) {
// if (pred == null) {
//
// continue;
//
// }
// if (retainSet.contains(pred)) {
//
// continue;
//
// }
// final int predDepth = gasState.getState(pred).depth.get();
//
// if (predDepth >= curDepth) {
//
// continue;
//
// }
if (!retainSet.contains(pred)) {
retainSet.add(pred);
visitPredecessors(gasState, pred, retainSet);
}
}
}