private static IEnumerable <DelayGraphVertex> GetFanouts(DelayGraphVertex v, DelayGraph graph)
{
IEnumerable <DelayGraphEdge> edges;
if (graph.TryGetOutEdges(v, out edges))
{
return(edges.Select(e => e.Target));
}
return(Enumerable.Empty <DelayGraphVertex>());
}
/// <summary>
/// prune edges from same source/target, keeping the strongr edge
/// </summary>
/// <param name="graph">a delay graph</param>
/// <returns>whether DG has changed</returns>
internal static bool PruneEdges(DelayGraph graph)
{
bool changed = false;
foreach (var vertex in graph.Vertices)
{
IEnumerable <DelayGraphEdge> edges;
if (!graph.TryGetOutEdges(vertex, out edges))
{
continue;
}
if (edges.Count() < 2)
{
continue;
}
// check for redundant out edges
var targets = new Dictionary <DelayGraphVertex, DelayGraphEdge>();
foreach (var edge in edges.ToList())
{
DelayGraphEdge prevEdge;
if (targets.TryGetValue(edge.Target, out prevEdge))
{
// decide which edge to keep and which to delete
if (prevEdge.Delay >= edge.Delay)
{
// keep prev edge
graph.RemoveEdge(edge);
}
else
{
targets[edge.Target] = edge;
graph.RemoveEdge(prevEdge);
}
changed = true;
}
else
{
targets[edge.Target] = edge;
}
}
}
return(changed);
}
