private long ShortcutPath(Path path, long delayDec, out Path xpath)
{
var segset = new SortedSet <SegLink>();
var seglist = new LinkedList <Pipe>();
long time = 0;
for (int i = 0; i < path.Segments.Length; i++)
{
Pipe seg = path.Segments[i];
time += seg.GetDelay(_a);
var pos = seglist.AddLast(seg);
segset.Add(new SegLink()
{
pos = pos, time = time
});
}
SegLink max = new SegLink()
{
pos = null, time = time + 1
};
SegLink minJoin = new SegLink()
{
pos = null, time = delayDec + 1
};
var joinset = segset.GetViewBetween(minJoin, max);
Debug.Assert(joinset.Any());
Hop bestSpliceHop = null;
Hop bestJoinHop = null;
long bestCost = long.MaxValue;
long bestJoinTime = -1;
foreach (var seglink in joinset)
{
long joinTime = seglink.time;
Pipe seg = seglink.pos.Value;
Hop joinHop = seg.GetSink(_a);
long joinCost = _a.Preds[joinHop.Node].Count();
if (joinCost < bestCost)
{
bestCost = joinCost;
bestJoinHop = joinHop;
bestJoinTime = joinTime;
bestSpliceHop = FindSpliceHop(segset, max, joinTime, delayDec);
}
long segDelay = seg.GetDelay(_a);
--joinTime;
if (segDelay > 1 && joinTime > delayDec && bestCost > 1)
{
bestCost = 1;
var insHop = new InsertionHop(_a, seg, segDelay - 1, 1);
bestJoinHop = insHop;
bestJoinTime = joinTime;
var left = seglist.AddBefore(seglink.pos, insHop.LeftPipe);
var right = seglist.AddAfter(seglink.pos, insHop.RightPipe);
seglist.Remove(seglink.pos);
segset.Remove(seglink);
var leftLink = new SegLink()
{
pos = left, time = seglink.time - 1
};
segset.Add(leftLink);
var rightLink = new SegLink()
{
pos = right, time = seglink.time
};
segset.Add(rightLink);
bestSpliceHop = FindSpliceHop(segset, max, joinTime, delayDec);
break;
}
}
long bestSpliceTime = bestJoinTime - delayDec - 1;
var newSegments = new List <Pipe>();
var wormhole = new InsertionPipe(bestSpliceHop, bestJoinHop, 1);
time = 0;
var curpos = seglist.First;
while (curpos != null)
{
Pipe seg = curpos.Value;
long nextTime = time + seg.GetDelay(_a);
if (nextTime <= bestSpliceTime || time >= bestJoinTime)
{
newSegments.Add(seg);
}
else if (time == bestSpliceTime)
{
newSegments.Add(wormhole);
}
else if (time < bestSpliceTime && nextTime > bestSpliceTime)
{
var joinHop = (InsertionHop)bestSpliceHop;
newSegments.Add(joinHop.LeftPipe);
newSegments.Add(wormhole);
}
time = nextTime;
curpos = curpos.Next;
}
xpath = new Path(_a, newSegments.ToArray());
return(bestCost + 1);
}
private bool FindCheapestPathConnection(Path srcPath, Path dstPath, long depTime, long arrTime, out Path xpath, out long cost)
{
long reqDelay = arrTime - depTime;
if (reqDelay < 2)
{
xpath = null;
cost = long.MaxValue;
return(false);
}
long bestCost = long.MaxValue;
xpath = null;
long srcDelay = srcPath.TotalDelay;
for (int i = srcPath.Segments.Length - 1; i >= 0; i--)
{
Pipe srcSeg = srcPath.Segments[i];
if (reqDelay > srcDelay)
{
long dstDelay = dstPath.TotalDelay;
long pathDelay = srcDelay + dstDelay;
for (int j = 0; j < dstPath.Segments.Length; j++)
{
Pipe dstSeg = dstPath.Segments[j];
if (reqDelay > pathDelay)
{
var node = dstSeg.GetSource(_a).Node;
if (!_a.IsEndpoint[node])
{
long joinCost = ComputeJoinCost(_a.Preds[dstSeg.GetSource(_a).Node]);
if (joinCost < bestCost)
{
var link = new InsertionPipe(srcSeg.GetSink(_a), dstSeg.GetSource(_a), reqDelay - pathDelay);
xpath = new Path(_a, new Pipe[] { link });
bestCost = joinCost;
}
}
long segDelay = dstSeg.GetDelay(_a);
if (segDelay >= 2 && bestCost > GetSplitJoinCost())
{
var join = new InsertionHop(_a, dstSeg, 1, segDelay - 1);
var link = new InsertionPipe(srcSeg.GetSink(_a), join, reqDelay - pathDelay + 1);
xpath = new Path(_a, new Pipe[] { link });
bestCost = GetSplitJoinCost();
}
if (bestCost == 0)
{
break;
}
}
pathDelay -= dstSeg.GetDelay(_a);
}
if (bestCost == 0)
{
break;
}
}
srcDelay -= srcSeg.GetDelay(_a);
}
// To be implemented
cost = bestCost + 1;
return(bestCost != long.MaxValue);
}
private long ExtendPath(Path path, long delayInc, out Path xpath)
{
Debug.Assert(delayInc >= 1);
if (path.TotalDelay <= 1)
{
Debug.Assert(path.Segments.Length == 1);
Tp pipe = path.Segments[0].Inst;
Pipe ipipe = new InsertionPipe((RealHop)_a.Source[pipe], (RealHop)_a.Sink[pipe], delayInc);
xpath = new Path(_a, new Pipe[] { ipipe });
long fanin = _a.Preds[_a.Sink[pipe]].Count();
return(fanin + 1);
}
Hop bestSpliceHop = null;
Hop bestJoinHop = null;
long bestCost = long.MaxValue;
int spliceIdx = -1;
int joinIdx = -1;
var segments = new List <Pipe>();
for (int i = 0; i < path.Segments.Length; i++)
{
Pipe seg = path.Segments[i];
Tp pipe = seg.Inst;
long delay = seg.GetDelay(_a);
Debug.Assert(delay > 0);
if (bestCost > 1)
{
if (delay == 1)
{
long cost = ComputeJoinCost(_a.Preds[_a.Sink[pipe]]);
if (cost < bestCost)
{
bestSpliceHop = (RealHop)_a.Source[pipe];
bestJoinHop = (RealHop)_a.Sink[pipe];
bestCost = cost;
spliceIdx = i;
joinIdx = i + 1;
}
segments.Add(seg);
}
if (bestCost > GetSplitJoinCost())
{
bestSpliceHop = (RealHop)_a.Source[pipe];
var ihop = new InsertionHop(_a, seg, 1, delay - 1);
bestJoinHop = ihop;
bestCost = 1;
spliceIdx = i;
joinIdx = i + 1;
segments.Add(ihop.LeftPipe);
segments.Add(ihop.RightPipe);
}
}
else
{
segments.Add(seg);
}
}
Pipe nose = new InsertionPipe(bestSpliceHop, bestJoinHop, delayInc + 1);
var newSegments = new List <Pipe>();
newSegments.AddRange(segments.Take(spliceIdx));
newSegments.Add(nose);
newSegments.AddRange(segments.Skip(joinIdx));
xpath = new Path(_a, newSegments.ToArray());
return(bestCost + 1);
}
