Changeset 386

Timestamp:

02/20/12 11:40:29 (13 years ago)

Author:

sherbold

Message:

• added method randomSequence(maxLength,validEnd) to the interface de.ugoe.cs.eventbench.models.IStochasticProcess (and implementing classes) to allow optimized generation of sessions of a pre-defined length.

Location:

trunk/EventBenchCore/src/de/ugoe/cs/eventbench/models

Files:

• IStochasticProcess.java (modified) (1 diff)
• TrieBasedModel.java (modified) (2 diffs)

trunk/EventBenchCore/src/de/ugoe/cs/eventbench/models/IStochasticProcess.java

@@ -59 +59 @@
          */
         public List<? extends Event<?>> randomSequence();
+
+        /**
+         * <p>
+         * Generates a random sequence of events. The sequence starts with
+         * {@link Event#STARTEVENT} and finishes with
+         * <ul>
+         * <li>{@link Event#ENDEVENT} if validEnd==true.</li>
+         * <li>b) if a generated sequences reaches {@link Event#ENDEVENT} before
+         * maxLength, the sequence finishes and is shorter than maxLenght.
+         * Otherwise, the sequence finishes as soon as maxLength is reached and the
+         * final event of the sequence must not be {@link Event#ENDEVENT}.</li>
+         * </ul>
+         * </p>
+         * 
+         * @param maxLength
+         *            maximum length of the generated sequence
+         * @param validEnd
+         *            if true, only sequences that finish with
+         *            {@link Event#ENDEVENT} are generated
+         * @return randomly generated sequence
+         * 
+         */
+        public List<? extends Event<?>> randomSequence(int maxLength,
+                        boolean validEnd);
 
         /**

trunk/EventBenchCore/src/de/ugoe/cs/eventbench/models/TrieBasedModel.java

@@ -143 +143 @@
         @Override
         public List<? extends Event<?>> randomSequence() {
+                return randomSequence(Integer.MAX_VALUE, true);
+        }
+
+        /*
+         * (non-Javadoc)
+         * 
+         * @see de.ugoe.cs.eventbench.models.IStochasticProcess#randomSequence()
+         */
+        @Override
+        public List<? extends Event<?>> randomSequence(int maxLength,
+                        boolean validEnd) {
                 List<Event<?>> sequence = new LinkedList<Event<?>>();
                 if (trie != null) {
-                        IncompleteMemory<Event<?>> context = new IncompleteMemory<Event<?>>(
-                                        trieOrder - 1);
-                        context.add(Event.STARTEVENT);
-
-                        Event<?> currentState = Event.STARTEVENT;
-
                         boolean endFound = false;
-
-                        while (!endFound) {
-                                double randVal = r.nextDouble();
-                                double probSum = 0.0;
-                                List<Event<?>> currentContext = context.getLast(trieOrder);
-                                for (Event<?> symbol : trie.getKnownSymbols()) {
-                                        probSum += getProbability(currentContext, symbol);
-                                        if (probSum >= randVal) {
-                                                endFound = (symbol == Event.ENDEVENT);
-                                                if (!(symbol == Event.STARTEVENT || symbol == Event.ENDEVENT)) {
-                                                        // only add the symbol the sequence if it is not
-                                                        // START
-                                                        // or END
-                                                        context.add(symbol);
-                                                        currentState = symbol;
-                                                        sequence.add(currentState);
+                        while (!endFound) { // outer loop for length checking
+                                sequence = new LinkedList<Event<?>>();
+                                IncompleteMemory<Event<?>> context = new IncompleteMemory<Event<?>>(
+                                                trieOrder - 1);
+                                context.add(Event.STARTEVENT);
+
+                                Event<?> currentState = Event.STARTEVENT;
+
+                                while (!endFound && sequence.size() < maxLength) {
+                                        double randVal = r.nextDouble();
+                                        double probSum = 0.0;
+                                        List<Event<?>> currentContext = context.getLast(trieOrder);
+                                        for (Event<?> symbol : trie.getKnownSymbols()) {
+                                                probSum += getProbability(currentContext, symbol);
+                                                if (probSum >= randVal) {
+                                                        if (!(symbol == Event.STARTEVENT || symbol == Event.ENDEVENT)) {
+                                                                // only add the symbol the sequence if it is not
+                                                                // START or END
+                                                                context.add(symbol);
+                                                                currentState = symbol;
+                                                                sequence.add(currentState);
+                                                        }
+                                                        endFound = (symbol == Event.ENDEVENT)
+                                                                        || (!validEnd && sequence.size() == maxLength);
+                                                        break;
                                                 }
-                                                break;
                                         }
                                 }
@@ -252 +265 @@
                 int i = 0;
                 for (Event<?> symbol : trie.getKnownSymbols()) {
-                        stateStrings[i] = symbol.toString();
+                        if (symbol.toString() == null) {
+                                stateStrings[i] = "null";
+                        } else {
+                                stateStrings[i] = symbol.toString();
+                        }
                         i++;
                 }