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Topological sort with roots in front (dont't mix outputs to inputs)
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136 changes: 136 additions & 0 deletions
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Cavern/Filters/Utilities/FilterGraphNodeUtils.Mapping.cs
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,136 @@ | ||
| using System; | ||
| using System.Collections.Generic; | ||
| using System.Linq; | ||
|
|
||
| namespace Cavern.Filters.Utilities { | ||
| public static partial class FilterGraphNodeUtils { | ||
| /// <summary> | ||
| /// Checks if a list of nodes is topologically sorted. | ||
| /// </summary> | ||
| public static bool IsTopologicalSort(this List<FilterGraphNode> orderedNodes) { | ||
| HashSet<FilterGraphNode> visited = new HashSet<FilterGraphNode>(); | ||
| for (int i = 0, c = orderedNodes.Count; i < c; i++) { | ||
| FilterGraphNode node = orderedNodes[i]; | ||
| IReadOnlyList<FilterGraphNode> children = node.Children; | ||
| for (int j = 0, childCount = children.Count; j < childCount; j++) { | ||
| if (visited.Contains(children[j])) { | ||
| return false; | ||
| } | ||
| } | ||
| visited.Add(node); | ||
| } | ||
| return true; | ||
| } | ||
|
|
||
| /// <summary> | ||
| /// Get all nodes in a filter graph knowing the root nodes. | ||
| /// </summary> | ||
| /// <param name="rootNodes">All nodes which have no parents</param> | ||
| public static HashSet<FilterGraphNode> MapGraph(this IEnumerable<FilterGraphNode> rootNodes) { | ||
| HashSet<FilterGraphNode> visited = new HashSet<FilterGraphNode>(); | ||
| Queue<FilterGraphNode> queue = new Queue<FilterGraphNode>(rootNodes); | ||
| while (queue.Count > 0) { | ||
| FilterGraphNode currentNode = queue.Dequeue(); | ||
| if (visited.Contains(currentNode)) { | ||
| continue; | ||
| } | ||
|
|
||
| visited.Add(currentNode); | ||
| foreach (FilterGraphNode child in currentNode.Children) { | ||
| queue.Enqueue(child); | ||
| } | ||
| } | ||
|
|
||
| return visited; | ||
| } | ||
|
|
||
| /// <summary> | ||
| /// Channel slot optimization: two non-parallel virtual channels should only occupy one virtual channel, but at different times. | ||
| /// </summary> | ||
| /// <param name="mapping">Node - channel mapping to optimize, virtual channels take negative indices</param> | ||
| public static void OptimizeChannelUse(this (FilterGraphNode node, int channel)[] mapping) { | ||
| int virtualChannels = -mapping.Min(x => x.channel); | ||
|
|
||
| // Partition channels to "time" intervals (mapping indices) | ||
| (int channel, int first, int last)[] intervals = new (int, int, int)[virtualChannels]; | ||
| for (int i = 0; i < intervals.Length; i++) { | ||
| intervals[i].channel = -1 - i; | ||
| intervals[i].first = -1; | ||
| } | ||
| for (int i = 0; i < mapping.Length; i++) { | ||
| int interval = -1 - mapping[i].channel; | ||
| if (interval < 0) { | ||
| continue; // Virtual channels only | ||
| } | ||
| if (intervals[interval].first == -1) { | ||
| intervals[interval].first = i; | ||
| } | ||
| intervals[interval].last = i; | ||
| } | ||
|
|
||
| // True creation is when the channel was separated, and true disappearance is when the channel was merged back | ||
| for (int i = 0; i < intervals.Length; i++) { | ||
| FilterGraphNode firstNode = mapping[intervals[i].first].node, | ||
| lastNode = mapping[intervals[i].last].node; | ||
| for (int j = 0; j < mapping.Length; j++) { | ||
| if (mapping[j].node.Children.Contains(firstNode)) { | ||
| intervals[i].first = j; | ||
| } | ||
| if (mapping[j].node.Parents.Contains(lastNode)) { | ||
| intervals[i].last = j; // Might never be merged, but it's not a problem, we get our thread back faster | ||
| } | ||
| } | ||
| } | ||
|
|
||
| // Interval graph optimization problem | ||
| Array.Sort(intervals, (a, b) => { | ||
| int first = a.first.CompareTo(b.first); | ||
| return first != 0 ? first : a.last.CompareTo(b.last); | ||
| }); | ||
|
|
||
| List<int> channelUsedUntil = new List<int>(); | ||
| for (int i = 0; i < intervals.Length; i++) { | ||
| int slots = channelUsedUntil.Count, | ||
| needFrom = intervals[i].first; | ||
| bool handled = false; | ||
| for (int slot = 0; slot < slots; slot++) { | ||
| if (channelUsedUntil[slot] <= needFrom) { | ||
| intervals[i].channel = -1 - slot; | ||
| channelUsedUntil[slot] = intervals[i].last; | ||
| handled = true; | ||
| break; | ||
| } | ||
| } | ||
|
|
||
| if (!handled) { | ||
| channelUsedUntil.Add(intervals[i].last); | ||
| intervals[i].channel = -channelUsedUntil.Count; | ||
| } | ||
| } | ||
| } | ||
|
|
||
| /// <summary> | ||
| /// Return all nodes on the graph in an order where every child is after its parents. | ||
| /// </summary> | ||
| public static List<FilterGraphNode> TopologicalSort(this FilterGraphNode[] rootNodes) { | ||
| List<FilterGraphNode> result = new List<FilterGraphNode>(); | ||
| HashSet<FilterGraphNode> visitedNodes = new HashSet<FilterGraphNode>(); | ||
|
|
||
| void VisitNode(FilterGraphNode node) { | ||
| if (visitedNodes.Contains(node)) { | ||
| return; | ||
| } | ||
| visitedNodes.Add(node); | ||
| foreach (FilterGraphNode child in node.Children) { | ||
| VisitNode(child); | ||
| } | ||
| result.Insert(0, node); | ||
| } | ||
|
|
||
| for (int i = 0; i < rootNodes.Length; i++) { | ||
| VisitNode(rootNodes[i]); | ||
| } | ||
| return result; | ||
| } | ||
| } | ||
| } |
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