[BUG] OutOPfMemory Error in propagator PropGraphCumulative

PropGraphCumulative is a propagator used by cumulative condition. This propagator uses a graph, which is backtrackable. Vertices of the graph are tasks and there is an edge between two vertices if their tasks overlap. When we go forward, the graph is getting smaller. When we backtrack, we have to return some edges to the graph. Method PropGraphCumulative.propagate(int evtmask) removes edges for every two vertices, when they stop to overlap.


Generally, maximum number of edges is O(N^2), where N is number of vertices (tasks). The while-cycle is break after 2*N vertices is searched. This means that some extra edges stays in the graph although they should be removed. This doesn’t influence a result but consumes a memory. When we need to schedule a lot tasks or we have more cumulative-constraints, it can cause OutOfMemory Error.

Suggested solution is remove the line number … but maybe it needs deepest research.