// DOES NOT DEAL WITH CIRCUITS WITH CYCLES!!!
private List <Gate> AssignTopologicalRanks()
{
// grab an item from the input set
var inEnum = InputAddrs.GetEnumerator();
inEnum.MoveNext();
var gateDeque = new LinkedList <Gate>();
while (inEnum.MoveNext())
{
gateDeque.AddFirst(inEnum.Current.Gate);
}
var sortList = new List <Gate>();
int nextRank = 0;
while (gateDeque.Count > 0)
{
var current = gateDeque.First.Value;
if (current.TopologicalRank != Gate.NO_RANK)
{
// already assigned a rank to this. can move on to next
gateDeque.RemoveFirst();
continue;
}
// check to see if all of the predecessors have a rank assigned. If any don't then add them to the front of the queue
bool shouldAssignRank = true;
for (int i = 0; i < current.InputCount; i++)
{
var addr = current.GetLocalInputAddress(i);
if (InputAddrs.Contains(addr))
{
continue;
}
var counterparty = InputConnectionCounterparties[addr].Gate;
if (counterparty.TopologicalRank == Gate.NO_RANK)
{
gateDeque.AddFirst(counterparty);
shouldAssignRank = false;
}
}
if (shouldAssignRank)
{
current.TopologicalRank = nextRank;
nextRank++;
sortList.Add(current);
gateDeque.RemoveFirst();
// add all successors
for (int i = 0; i < current.OutputCount; i++)
{
var addr = current.GetLocalOutputAddress(i);
if (OutputAddrs.Contains(addr))
{
continue;
}
gateDeque.AddLast(OutputConnectionCounterparties[addr].Gate);
}
}
// otherwise a predecessor still needs a rank
}
return(sortList);
}