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Networks engine for netroles library
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/*
* This file is part of netroles.
*
* netroles is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* netroles is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with netroles. If not, see neighbors, final PrimitiveIterable.OfInt starts,
final Visitor visitor) {
Objects.requireNonNull(neighbors);
Objects.requireNonNull(starts);
Objects.requireNonNull(visitor);
final Mapping.OfInt bfsns = Mappings.newIntList(-1, numVertices);
for (final int i : starts) {
if (bfsns.getInt(i) < 0) {
bfs(neighbors, bfsns, i, visitor);
}
}
return bfsns;
}
/**
* Single source breadth-first-search.
*
* @param neighbors
* Neighbourhood function.
* @param bfsns
* BFS number mapping, will be filled on visiting nodes.
* @param start
* The starting node.
* @param visitor
* A traversal visitor. Use {@link Visitor#NULL} instead of {@code null}.
*/
private static void bfs(final IntFunction neighbors,
final Mapping.OfInt bfsns, final int start, final Visitor visitor) {
visitor.startSearch(start);
bfsns.setInt(start, 0);
visitor.visitVertex(start);
final PrimitiveList.OfInt queue = Mappings.newIntList(); // manually managed fifo
queue.addInt(start);
int queueHead = 0;
while (queueHead != queue.size()) {
final int source = queue.getInt(queueHead++);
final int sourceBfsn1 = bfsns.getInt(source) + 1;
final PrimitiveIterator.OfInt out = neighbors.apply(source).iterator();
while (out.hasNext()) {
final int target = out.nextInt();
if (bfsns.getInt(target) < 0) {
bfsns.setInt(target, sourceBfsn1);
queue.addInt(target);
visitor.visitEdge(source, target, -1);
visitor.visitVertex(target);
}
}
// keep queue store small
if (2 * queueHead > queue.size()) {
queue.removeRange(0, queueHead);
queueHead = 0;
}
}
visitor.endSearch();
}
/**
* Multi source depth-first-search.
*
* @param numVertices
* Number of nodes.
* @param neighbors
* Neighbourhood function.
* @param starts
* Start points. A new DFS is started from each of these nodes if the DFS number is still
* negative.
* @param visitor
* A traversal visitor. Use {@link Visitor#NULL} instead of {@code null}.
* @return the DFS number mapping.
*/
@Override
public Mapping.OfInt dfs(final int numVertices,
final IntFunction neighbors, final PrimitiveIterable.OfInt starts,
final Visitor visitor) {
Objects.requireNonNull(neighbors);
Objects.requireNonNull(starts);
Objects.requireNonNull(visitor);
final Mapping.OfInt dfsns = Mappings.newIntList(-1, numVertices);
dfsInternal(neighbors, starts, dfsns, visitor);
return dfsns;
}
/**
* Multi source depth-first-search.
*
* @param neighbors
* Neighbourhood function.
* @param starts
* Start points. A new DFS is started from each of these nodes if the DFS number is still
* negative.
* @param dfsns
* Mapping as storage for DFS numbers.
* @param visitor
* A traversal visitor. Use {@link Visitor#NULL} instead of {@code null}.
*/
@Override
public void dfs(final IntFunction neighbors,
final PrimitiveIterable.OfInt starts, final Mapping.OfInt dfsns, final Visitor visitor) {
Objects.requireNonNull(neighbors);
Objects.requireNonNull(starts);
Objects.requireNonNull(visitor);
Objects.requireNonNull(dfsns);
dfsInternal(neighbors, starts, dfsns, visitor);
}
@Override
public void edgeDfs(final int numEdges, IntFunction> edges,
final PrimitiveIterable.OfInt starts, final Mapping.OfInt dfsns, final Visitor visitor) {
Objects.requireNonNull(edges);
Objects.requireNonNull(starts);
Objects.requireNonNull(visitor);
final boolean[] edgeMark = new boolean[numEdges];
for (final int i : starts) {
if (dfsns.getInt(i) < 0) {
edgeDfsInternal(edges, dfsns, i, visitor, edgeMark);
}
}
}
/**
* Multi source depth-first-search.
*
* @param neighbors
* Neighbourhood function.
* @param starts
* Start points. A new DFS is started from each of these nodes if the DFS number is still
* negative.
* @param dfsns
* Mapping as storage for DFS numbers.
* @param visitor
* A traversal visitor. Use {@link Visitor#NULL} instead of {@code null}.
*/
private static void dfsInternal(final IntFunction neighbors,
final PrimitiveIterable.OfInt starts, final Mapping.OfInt dfsns, final Visitor visitor) {
for (final int i : starts) {
if (dfsns.getInt(i) < 0) {
dfsInternal(neighbors, dfsns, i, visitor);
}
}
}
/**
* Single source depth-first-search.
*
* @param neighbors
* Neighbourhood function.
* @param dfsns
* DFS number mapping, will be filled on visiting nodes.
* @param start
* The starting node.
* @param visitor
* A traversal visitor. Use {@link Visitor#NULL} instead of {@code null}.
*/
private static Mapping.OfInt dfsInternal(final IntFunction neighbors,
final Mapping.OfInt dfsns, final int start, final Visitor visitor) {
visitor.startSearch(start);
final PrimitiveList.OfInt vertexStack = Mappings.newIntList();
final Stack neighborTraversalStack = new Stack<>();
int dfsn = 0;
vertexStack.addInt(start);
neighborTraversalStack.push(neighbors.apply(start).iterator());
while (!vertexStack.isEmpty()) {
final int source = vertexStack.getInt(vertexStack.size() - 1);
PrimitiveIterator.OfInt neighborIterator = neighborTraversalStack.peek();
if (dfsns.getInt(source) < 0) {
dfsns.setInt(source, dfsn++);
visitor.visitVertex(source);
}
if (!neighborIterator.hasNext()) {
visitor.backtrackVertex(source);
vertexStack.removeIndex(vertexStack.size() - 1);
neighborTraversalStack.pop();
} else {
int target = neighborIterator.nextInt();
if (dfsns.getInt(target) < 0) {
vertexStack.addInt(target);
neighborTraversalStack.push(neighbors.apply(target).iterator());
}
visitor.visitEdge(source, target, -1);
}
}
visitor.endSearch();
return dfsns;
}
private static Mapping.OfInt edgeDfsInternal(final IntFunction> edges,
final Mapping.OfInt dfsns, final int start, final Visitor visitor, boolean[] edgeMark) {
visitor.startSearch(start);
final PrimitiveList.OfInt vertexStack = Mappings.newIntList();
final Stack> neighborTraversalStack = new Stack<>();
int dfsn = 0;
vertexStack.addInt(start);
neighborTraversalStack.push(edges.apply(start).iterator());
while (!vertexStack.isEmpty()) {
final int source = vertexStack.getInt(vertexStack.size() - 1);
Iterator edgeIterator = neighborTraversalStack.peek();
if (dfsns.getInt(source) < 0) {
dfsns.setInt(source, dfsn++);
visitor.visitVertex(source);
}
if (!edgeIterator.hasNext()) {
visitor.backtrackVertex(source);
vertexStack.removeIndex(vertexStack.size() - 1);
neighborTraversalStack.pop();
} else {
Edge edge = edgeIterator.next();
int idx = edge.getIndex();
if (!edgeMark[idx]) {
edgeMark[idx] = true;
int target = edge.getTarget();
if (dfsns.getInt(target) < 0) {
vertexStack.addInt(target);
neighborTraversalStack.push(edges.apply(target).iterator());
}
visitor.visitEdge(source, target, idx);
}
}
}
visitor.endSearch();
return dfsns;
}
}