private void initialize(final LGraph graph) {
layeredGraph = graph;
int layerCount = graph.getLayers().size();
bestNodeOrder = new LNode[layerCount][];
currentNodeOrder = new LNode[layerCount][];
originalNodeOrder = new LNode[layerCount][];
ListIterator<Layer> layerIter = graph.getLayers().listIterator();
while (layerIter.hasNext()) {
Layer layer = layerIter.next();
int layerNodeCount = layer.getNodes().size();
assert layerNodeCount > 0;
int layerIndex = layerIter.previousIndex();
bestNodeOrder[layerIndex] = new LNode[layerNodeCount];
currentNodeOrder[layerIndex] = new LNode[layerNodeCount];
originalNodeOrder[layerIndex] = new LNode[layerNodeCount];
ListIterator<LNode> nodeIter = layer.getNodes().listIterator();
int id = 0;
while (nodeIter.hasNext()) {
LNode node = nodeIter.next();
node.id = id++;
currentNodeOrder[layerIndex][nodeIter.previousIndex()] = node;
bestNodeOrder[layerIndex][nodeIter.previousIndex()] = node;
originalNodeOrder[layerIndex][nodeIter.previousIndex()] = node;
}
}
crossingCounter = new AllCrossingsCounter(currentNodeOrder);
if (greedySwitchType.useHyperedgeCounter()) {
crossingCounter.useHyperedgeCounter();
}
}
/**
* Splits this linear segment before the given node. The returned segment contains all nodes
* from the given node onward, with their ID set to the new segment's ID. Those nodes are
* removed from this segment.
*
* @param node the node to split the segment at.
* @param newId the new segment's id.
* @return new linear segment with ID {@code -1} and all nodes from {@code node} onward.
*/
LinearSegment split(final LNode node, final int newId) {
int nodeIndex = nodes.indexOf(node);
// Prepare the new segment
LinearSegment newSegment = new LinearSegment();
newSegment.id = newId;
// Move nodes to the new segment
ListIterator<LNode> iterator = nodes.listIterator(nodeIndex);
while (iterator.hasNext()) {
LNode movedNode = iterator.next();
movedNode.id = newId;
newSegment.nodes.add(movedNode);
iterator.remove();
}
return newSegment;
}
/**
* Put a node into the given linear segment and check for following parts of a long edge.
*
* @param node the node to put into the linear segment
* @param segment a linear segment
* @return {@code true} if the given node was not already part of another segment and was thus
* added to the given segment.
*/
private boolean fillSegment(final LNode node, final LinearSegment segment) {
NodeType nodeType = node.getType();
// handle initial big nodes as big node type
if (node.getProperty(InternalProperties.BIG_NODE_INITIAL)) {
nodeType = NodeType.BIG_NODE;
}
if (node.id >= 0) {
// The node is already part of another linear segment
return false;
} else if (segment.nodeType != null
&& (nodeType == NodeType.BIG_NODE && nodeType != segment.nodeType)) {
// Big nodes are not allowed to share a linear segment with other dummy nodes
return false;
} else {
// Add the node to the given linear segment
node.id = segment.id;
segment.nodes.add(node);
}
segment.nodeType = nodeType;
if (nodeType == NodeType.LONG_EDGE
|| nodeType == NodeType.NORTH_SOUTH_PORT
|| nodeType == NodeType.BIG_NODE) {
// This is a LONG_EDGE, NORTH_SOUTH_PORT or BIG_NODE dummy; check if any of its
// successors are of one of these types too. If so, we can form a linear segment
// with one of them. (not with more than one, though)
// Note 1: LONG_EDGES and NORTH_SOUTH_PORTs can share a common linear segment
// Note 2: we must take care not to make a segment out of nodes that are in the same layer
// Note 3: for BIG_NODEs also the first BIG_NODE_INITIAL which is no actual dummy node has
// to be considered here
for (LPort sourcePort : node.getPorts()) {
for (LPort targetPort : sourcePort.getSuccessorPorts()) {
LNode targetNode = targetPort.getNode();
NodeType targetNodeType = targetNode.getType();
if (node.getLayer() != targetNode.getLayer()) {
if (nodeType == NodeType.BIG_NODE) {
// current AND the next node are BIG_NODE dummies
if (targetNodeType == NodeType.BIG_NODE) {
if (fillSegment(targetNode, segment)) {
// We just added another node to this node's linear segment.
// That's quite enough.
return true;
}
}
} else {
// current no bignode and next node is LONG_EDGE and NORTH_SOUTH_PORT
if (targetNodeType == NodeType.LONG_EDGE
|| targetNodeType == NodeType.NORTH_SOUTH_PORT) {
if (fillSegment(targetNode, segment)) {
// We just added another node to this node's linear segment.
// That's quite enough.
return true;
}
}
}
}
}
}
}
return true;
}
/**
* Sorts the linear segments of the given layered graph by finding a topological ordering in the
* corresponding segment ordering graph.
*
* @param layeredGraph layered graph to process
* @return a sorted array of linear segments
*/
private LinearSegment[] sortLinearSegments(final LGraph layeredGraph) {
// set the identifier and input / output priority for all nodes
List<LinearSegment> segmentList = Lists.newArrayList();
for (Layer layer : layeredGraph) {
for (LNode node : layer) {
node.id = -1;
int inprio = Integer.MIN_VALUE, outprio = Integer.MIN_VALUE;
for (LPort port : node.getPorts()) {
for (LEdge edge : port.getIncomingEdges()) {
int prio = edge.getProperty(InternalProperties.PRIORITY);
inprio = Math.max(inprio, prio);
}
for (LEdge edge : port.getOutgoingEdges()) {
int prio = edge.getProperty(InternalProperties.PRIORITY);
outprio = Math.max(outprio, prio);
}
}
node.setProperty(INPUT_PRIO, inprio);
node.setProperty(OUTPUT_PRIO, outprio);
}
}
// create linear segments for the layered graph, ignoring odd port side dummies
int nextLinearSegmentID = 0;
for (Layer layer : layeredGraph) {
for (LNode node : layer) {
// Test for the node ID; calls to fillSegment(...) may have caused the node ID
// to be != -1.
if (node.id < 0) {
LinearSegment segment = new LinearSegment();
segment.id = nextLinearSegmentID++;
fillSegment(node, segment);
segmentList.add(segment);
}
}
}
// create and initialize segment ordering graph
List<List<LinearSegment>> outgoingList = Lists.newArrayListWithCapacity(segmentList.size());
List<Integer> incomingCountList = Lists.newArrayListWithCapacity(segmentList.size());
for (int i = 0; i < segmentList.size(); i++) {
outgoingList.add(new ArrayList<LinearSegment>());
incomingCountList.add(0);
}
// create edges for the segment ordering graph
createDependencyGraphEdges(layeredGraph, segmentList, outgoingList, incomingCountList);
// turn lists into arrays
LinearSegment[] segments = segmentList.toArray(new LinearSegment[segmentList.size()]);
@SuppressWarnings("unchecked")
List<LinearSegment>[] outgoing = outgoingList.toArray(new List[outgoingList.size()]);
int[] incomingCount = new int[incomingCountList.size()];
for (int i = 0; i < incomingCount.length; i++) {
incomingCount[i] = incomingCountList.get(i);
}
// gather the sources of the segment ordering graph
int nextRank = 0;
List<LinearSegment> noIncoming = Lists.newArrayList();
for (int i = 0; i < segments.length; i++) {
if (incomingCount[i] == 0) {
noIncoming.add(segments[i]);
}
}
// find a topological ordering of the segment ordering graph
int[] newRanks = new int[segments.length];
while (!noIncoming.isEmpty()) {
LinearSegment segment = noIncoming.remove(0);
newRanks[segment.id] = nextRank++;
while (!outgoing[segment.id].isEmpty()) {
LinearSegment target = outgoing[segment.id].remove(0);
incomingCount[target.id]--;
if (incomingCount[target.id] == 0) {
noIncoming.add(target);
}
}
}
// apply the new ordering to the array of linear segments
linearSegments = new LinearSegment[segments.length];
for (int i = 0; i < segments.length; i++) {
assert outgoing[i].isEmpty();
LinearSegment ls = segments[i];
int rank = newRanks[i];
linearSegments[rank] = ls;
ls.id = rank;
for (LNode node : ls.nodes) {
node.id = rank;
}
}
return linearSegments;
}