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1 | /* | |
2 | * Copyright (c) 2003, the JUNG Project and the Regents of the University | |
3 | * of California | |
4 | * All rights reserved. | |
5 | * | |
6 | * This software is open-source under the BSD license; see either | |
7 | * "license.txt" or | |
8 | * http://jung.sourceforge.net/license.txt for a description. | |
9 | */ | |
10 | /* | |
11 | * Created on Apr 21, 2004 | |
12 | */ | |
13 | package edu.uci.ics.jung.algorithms.transformation; | |
14 | ||
15 | import java.util.HashMap; | |
16 | import java.util.HashSet; | |
17 | import java.util.Iterator; | |
18 | import java.util.Map; | |
19 | import java.util.Set; | |
20 | ||
21 | import org.apache.commons.collections.BidiMap; | |
22 | import org.apache.commons.collections.Predicate; | |
23 | ||
24 | import edu.uci.ics.jung.graph.ArchetypeVertex; | |
25 | import edu.uci.ics.jung.graph.Edge; | |
26 | import edu.uci.ics.jung.graph.Element; | |
27 | import edu.uci.ics.jung.graph.Graph; | |
28 | import edu.uci.ics.jung.graph.Hypergraph; | |
29 | import edu.uci.ics.jung.graph.KPartiteGraph; | |
30 | import edu.uci.ics.jung.graph.Vertex; | |
31 | import edu.uci.ics.jung.graph.decorators.NumberEdgeValue; | |
32 | import edu.uci.ics.jung.graph.impl.DirectedSparseEdge; | |
33 | import edu.uci.ics.jung.graph.impl.DirectedSparseGraph; | |
34 | import edu.uci.ics.jung.graph.impl.UndirectedSparseEdge; | |
35 | import edu.uci.ics.jung.graph.impl.UndirectedSparseGraph; | |
36 | import edu.uci.ics.jung.utils.GraphUtils; | |
37 | import edu.uci.ics.jung.utils.PredicateUtils; | |
38 | import edu.uci.ics.jung.utils.TypedVertexGenerator; | |
39 | import edu.uci.ics.jung.utils.UserData; | |
40 | import edu.uci.ics.jung.utils.VertexGenerator; | |
41 | import edu.uci.ics.jung.utils.UserDataContainer.CopyAction; | |
42 | ||
43 | /** | |
44 | * A class for creating a "folded" graph based on a k-partite graph or a | |
45 | * hypergraph. | |
46 | * | |
47 | * <p>A "folded" graph is derived from a k-partite graph by identifying | |
48 | * a partition of vertices which will become the vertices of the new graph, copying | |
49 | * these vertices into the new graph, and then connecting those vertices whose | |
50 | * original analogues were connected indirectly through elements | |
51 | * of other partitions. (See <code>fold(KPartiteGraph, Predicate, NumberEdgeValue)</code> | |
52 | * for more details.)</p> | |
53 | * | |
54 | * <p>A "folded" graph is derived from a hypergraph by creating vertices based on | |
55 | * either the vertices or the hyperedges of the original graph, and connecting | |
56 | * vertices in the new graph if their corresponding vertices/hyperedges share a | |
57 | * connection with a common hyperedge/vertex. (See <code>fold(Hypergraph, | |
58 | * boolean, NumberEdgeValue)</code> for more details.)</p> | |
59 | * | |
60 | * @author Danyel Fisher | |
61 | * @author Joshua O'Madadhain | |
62 | */ | |
63 | public class FoldingTransformer | |
64 | { | |
65 | /** | |
66 | * Used in <code>fold()</code> as a user data key to the data attached to | |
67 | * the edges in the folded graph. | |
68 | */ | |
69 | public static final String FOLDED_DATA = "edu.uci.ics.jung.graph.KPartiteFolder:Folded Data"; | |
70 | ||
71 | protected boolean parallel; | |
72 | 2 | protected CopyAction copy_action = UserData.REMOVE; |
73 | ||
74 | /** | |
75 | * Specifies whether the graph being folded is undirected or not. | |
76 | * Set by <code>checkGraphConstraints</code>. | |
77 | */ | |
78 | private boolean undirected; | |
79 | ||
80 | /** | |
81 | * Creates an instance of this Folder. See the discussion of fold for notes | |
82 | * on the "parallel" argument. | |
83 | * | |
84 | */ | |
85 | 2 | public FoldingTransformer(boolean parallel) { |
86 | 2 | this.parallel = parallel; |
87 | 2 | } |
88 | ||
89 | /** | |
90 | * Specifies whether the folded graphs create parallel edges or a decorated | |
91 | * single edge. | |
92 | * @param parallel | |
93 | */ | |
94 | public void setParallel(boolean parallel) { | |
95 | 0 | this.parallel = parallel; |
96 | 0 | } |
97 | ||
98 | /** | |
99 | * Specifies the copy action used to attach data to edges. | |
100 | * @param copy_action | |
101 | */ | |
102 | public void setCopyAction(CopyAction copy_action) | |
103 | { | |
104 | 0 | this.copy_action = copy_action; |
105 | 0 | } |
106 | ||
107 | /** | |
108 | * Equivalent to <code>fold(g, p, null)</code>. | |
109 | */ | |
110 | public Graph fold(KPartiteGraph g, Predicate p) | |
111 | { | |
112 | 2 | return fold(g, p, null); |
113 | } | |
114 | ||
115 | /** | |
116 | * <p> | |
117 | * Converts <code>g</code> into a unipartite graph whose vertex set is the | |
118 | * vertices whose partition is specified by <code>p</code>. For vertices | |
119 | * <code>a</code> and <code>b</code> in this partition, the resultant | |
120 | * graph will include the edge <code>(a,b)</code> if the original graph | |
121 | * contains edges <code>(a,c)</code> and <code>(c,b)</code> for at least | |
122 | * one vertex <code>c</code>. | |
123 | * </p> | |
124 | * | |
125 | * <p> | |
126 | * If <code>parallel</code> is true, then each such connecting vertex | |
127 | * <code>c</code> will be represented by a single edge in the resultant | |
128 | * graph, and the resultant graph may therefore contain parallel edges. | |
129 | * Otherwise, each edge <code>(a,b)</code> in the resultant graph will be | |
130 | * annotated with the set of vertices <code>c</code> that connected | |
131 | * <code>a</code> to <code>b</code> in the original graph, and the | |
132 | * graph's edge requirements will be set to refuse parallel edges. | |
133 | * </p> | |
134 | * | |
135 | * <p>In either case, if the original graph contains both a directed edge from | |
136 | * <code>a</code> to <code>b</code>, and a directed edge from <code>b</code> | |
137 | * <code>a</code>, then a self-loop will be created from <code>a</code> | |
138 | * to itself in the folded graph. Undirected edges do not result in | |
139 | * self-loops. | |
140 | * </p> | |
141 | * | |
142 | * <p> | |
143 | * If <code>g</code> is neither strictly directed nor strictly undirected, | |
144 | * this method throws <code>IllegalArgumentException</code>. Parallel edges | |
145 | * in the original graph have no effect on the resultant graph: only one edge | |
146 | * <code>(a,c)</code> and one edge <code>(c,b)</code> are necessary to | |
147 | * induce a connection between <code>a</code> and <code>b</code> in the folded | |
148 | * graph, and any additional such edges are ignored.</p> | |
149 | * | |
150 | * <p>If <code>nev</code> is null, | |
151 | * adds the connecting element as a decoration on the corresponding edge in the new | |
152 | * graph; otherwise, sets the weight of each edge to the number of parallel | |
153 | * paths between the corresponding vertices in the original graph that are | |
154 | * encountered in the folding process.</p> | |
155 | * | |
156 | * @param g the graph to fold | |
157 | * @param p the predicate which specifies the partition to fold into | |
158 | * @return the folded graph | |
159 | * @throws IllegalArgumentException | |
160 | */ | |
161 | public Graph fold(KPartiteGraph g, Predicate p, NumberEdgeValue nev) | |
162 | { | |
163 | 2 | checkGraphConstraints(g); |
164 | ||
165 | 2 | Graph newGraph = createGraph(); |
166 | ||
167 | // get vertices for the specified partition, copy into new graph | |
168 | 2 | Set vertices = PredicateUtils.getVertices(g, p); |
169 | 2 | for (Iterator iter = vertices.iterator(); iter.hasNext();) { |
170 | 6 | ArchetypeVertex v = (ArchetypeVertex) iter.next(); |
171 | 6 | v.copy(newGraph); |
172 | } | |
173 | ||
174 | 2 | for (Iterator iter = vertices.iterator(); iter.hasNext();) { |
175 | 6 | Vertex v = (Vertex) iter.next(); |
176 | 6 | Vertex v_new = (Vertex) v.getEqualVertex(newGraph); |
177 | 6 | Set succs = v.getSuccessors(); |
178 | ||
179 | 6 | for (Iterator s_iter = succs.iterator(); s_iter.hasNext();) { |
180 | 10 | Vertex s = (Vertex) s_iter.next(); |
181 | 10 | Set s_succs = s.getSuccessors(); |
182 | ||
183 | 10 | for (Iterator t_iter = s_succs.iterator(); t_iter.hasNext();) { |
184 | 13 | Vertex t = (Vertex) t_iter.next(); |
185 | ||
186 | // if t is in the partition of interest | |
187 | // and has not been covered (undirected graphs only) | |
188 | 13 | if (!vertices.contains(t)) continue; |
189 | ||
190 | 13 | Vertex t_new = (Vertex) t.getEqualVertex(newGraph); |
191 | 13 | addEdge(newGraph, v_new, s, t_new, nev); |
192 | ||
193 | } | |
194 | } | |
195 | } | |
196 | 2 | return newGraph; |
197 | } | |
198 | ||
199 | // /** | |
200 | // * Equivalent to <code>fold(h, use_vertices, null)</code>. | |
201 | // */ | |
202 | // public Graph fold(Hypergraph h, boolean use_vertices) | |
203 | // { | |
204 | // return fold(h, use_vertices, null); | |
205 | // } | |
206 | // | |
207 | // public Graph fold(Hypergraph h, boolean use_vertices, NumberEdgeValue nev) | |
208 | // { | |
209 | // return fold(h, null, use_vertices, nev, new BidirectionalHashMap()); | |
210 | // } | |
211 | ||
212 | /** | |
213 | * Creates a <code>Graph</code> which is a "folded" version of <code>h</code>. | |
214 | * | |
215 | * <p>If <code>use_vertices</code> is true, the vertices of the new graph | |
216 | * correspond to the vertices of <code>h</code>, and <code>a</code> | |
217 | * is connected to <code>b</code> in the new graph if the corresponding vertices | |
218 | * in <code>h</code> are connected by a hyperedge. Thus, each hyperedge with | |
219 | * <i>k</i> vertices in <code>h</code> would induce a <i>k</i>-clique in the new graph.</p> | |
220 | * | |
221 | * <p>If <code>use_vertices</code> is false, then the vertices of the new | |
222 | * graph correspond to the hyperedges of <code>h</code>, and <code>a</code> | |
223 | * is connected to <code>b</code> in the new graph if the corresponding hyperedges | |
224 | * in <code>h</code> share a vertex. Thus, each vertex connected to <i>k</i> | |
225 | * hyperedges in <code>h</code> would induce a <i>k</i>-clique in the new graph.</p> | |
226 | * | |
227 | * <p>If <code>nev</code> is null, | |
228 | * adds the connecting element as a decoration on the corresponding edge in the new | |
229 | * graph; otherwise, sets the weight of each edge to the number of parallel | |
230 | * paths between the corresponding vertices in the original graph that are | |
231 | * encountered in the folding process.</p> | |
232 | */ | |
233 | public Graph fold(Hypergraph h, Graph target, boolean use_vertices, NumberEdgeValue nev, BidiMap map) | |
234 | { | |
235 | 0 | undirected = true; |
236 | ||
237 | 0 | if (target == null) |
238 | 0 | target = createGraph(); |
239 | ||
240 | 0 | VertexGenerator vg = GraphUtils.getVertexGenerator(target); |
241 | 0 | if (vg == null) |
242 | 0 | vg = new TypedVertexGenerator(target); |
243 | ||
244 | 0 | Map m = new HashMap(); |
245 | Set vertices; | |
246 | Set edges; | |
247 | ||
248 | // vertices and hyperedges are duals of one another; we can treat | |
249 | // them equivalently for this purpose | |
250 | 0 | if (use_vertices) |
251 | { | |
252 | 0 | vertices = h.getVertices(); |
253 | 0 | edges = h.getEdges(); |
254 | } | |
255 | else | |
256 | { | |
257 | 0 | vertices = h.getEdges(); |
258 | 0 | edges = h.getVertices(); |
259 | } | |
260 | ||
261 | // create vertices: | |
262 | // for each "vertex", create a new vertex and import user data | |
263 | 0 | for (Iterator iter = vertices.iterator(); iter.hasNext(); ) |
264 | { | |
265 | 0 | Element av = (Element)iter.next(); |
266 | 0 | Vertex v = vg.create(); |
267 | 0 | v.importUserData(av); |
268 | 0 | target.addVertex(v); |
269 | 0 | m.put(av, v); |
270 | 0 | map.put(v, av); |
271 | } | |
272 | ||
273 | // create edges: | |
274 | // for each "hyperedge", create an edge between each incident vertex pair | |
275 | 0 | for (Iterator iter = edges.iterator(); iter.hasNext(); ) |
276 | { | |
277 | 0 | Element he = (Element)iter.next(); |
278 | 0 | Set elts = he.getIncidentElements(); |
279 | 0 | Vertex[] v_array = new Vertex[elts.size()]; |
280 | 0 | int i = 0; |
281 | 0 | for (Iterator e_iter = elts.iterator(); e_iter.hasNext(); ) |
282 | 0 | v_array[i++] = (Vertex)(m.get(e_iter.next())); |
283 | 0 | for (i = 0; i < v_array.length; i++) |
284 | 0 | for (int j = i + 1; j < v_array.length; j++) |
285 | 0 | addEdge(target, v_array[i], he, v_array[j], nev); |
286 | } | |
287 | ||
288 | 0 | return target; |
289 | } | |
290 | ||
291 | ||
292 | /** | |
293 | * Creates a new edge from <code>firstEnd</code> to <code>secondEnd</code> | |
294 | * in <code>newGraph</code>. Note that | |
295 | * <code>firstEnd</code> and <code>secondEnd</code> are both parts of | |
296 | * <code>newGraph</code>, while | |
297 | * <code>intermediate</code> is part of the original graph. If <code>parallel</code> is set, | |
298 | * adds a new edge from <code>firstEnd</code> to <code>secondEnd</code>. | |
299 | * If <code>parallel</code> is not set, then (as appropriate) adds an edge | |
300 | * or creates one from <code>firstEnd</code> to <code>secondEnd</code>. | |
301 | */ | |
302 | protected void addEdge(Graph newGraph, Vertex firstEnd, | |
303 | Element intermediate, Vertex secondEnd, NumberEdgeValue nev) | |
304 | { | |
305 | 13 | if( undirected && firstEnd == secondEnd ) return; |
306 | 8 | if (parallel) { |
307 | Edge v_t; | |
308 | 4 | if (undirected) |
309 | 0 | v_t = new UndirectedSparseEdge(firstEnd, secondEnd); |
310 | else | |
311 | 4 | v_t = new DirectedSparseEdge(firstEnd, secondEnd); |
312 | 4 | if (nev != null) |
313 | 0 | nev.setNumber(v_t, new Integer(1)); |
314 | else | |
315 | 4 | v_t.addUserDatum(FOLDED_DATA, intermediate, copy_action); |
316 | 4 | newGraph.addEdge(v_t); |
317 | } else { | |
318 | 4 | Edge v_t = firstEnd.findEdge(secondEnd); |
319 | 4 | if (v_t == null) { |
320 | 1 | if (undirected) |
321 | 1 | v_t = new UndirectedSparseEdge(firstEnd, secondEnd); |
322 | else | |
323 | 0 | v_t = new DirectedSparseEdge(firstEnd, secondEnd); |
324 | 1 | if (nev != null) |
325 | 0 | nev.setNumber(v_t, new Integer(0)); |
326 | else | |
327 | 1 | v_t.addUserDatum(FOLDED_DATA, new HashSet(), copy_action); |
328 | 1 | newGraph.addEdge(v_t); |
329 | } | |
330 | 4 | if (nev != null) |
331 | 0 | nev.setNumber(v_t, new Integer(nev.getNumber(v_t).intValue() + 1)); |
332 | else | |
333 | { | |
334 | 4 | Set folded_vertices = (Set) v_t.getUserDatum(FOLDED_DATA); |
335 | 4 | folded_vertices.add(intermediate); |
336 | } | |
337 | } | |
338 | 8 | } |
339 | ||
340 | /** | |
341 | * Returns a base graph to use. | |
342 | */ | |
343 | protected Graph createGraph() | |
344 | { | |
345 | Graph newGraph; | |
346 | 2 | if (undirected) |
347 | 1 | newGraph = new UndirectedSparseGraph(); |
348 | else | |
349 | 1 | newGraph = new DirectedSparseGraph(); |
350 | ||
351 | 2 | if (parallel) |
352 | 1 | newGraph.getEdgeConstraints().remove(Graph.NOT_PARALLEL_EDGE); |
353 | ||
354 | 2 | return newGraph; |
355 | } | |
356 | ||
357 | /** | |
358 | * Checks for, and rejects, mixed-mode graphs, and sets the <code>undirected</code> | |
359 | * class variable state. | |
360 | */ | |
361 | protected void checkGraphConstraints(KPartiteGraph g) { | |
362 | 2 | undirected = PredicateUtils.enforcesUndirected(g); |
363 | 2 | if (!undirected && !PredicateUtils.enforcesDirected(g)) |
364 | 0 | throw new IllegalArgumentException( |
365 | "Graph must be strictly " | |
366 | + "directed or strictly undirected (no mixed graphs allowed)"); | |
367 | 2 | } |
368 | ||
369 | } |
this report was generated by version 1.0.5 of jcoverage. |
copyright © 2003, jcoverage ltd. all rights reserved. |