Changeset 7

Timestamp:

04/13/11 13:21:28 (13 years ago)

Author:

sherbold

Message:

• changed PPM to work with Event<?> instead of String

Location:

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

Files:

• data/Event.java (modified) (1 diff)
• ppm/PredictionByPartialMatch.java (modified) (7 diffs)

trunk/EventBenchCore/src/de/ugoe/cs/eventbench/data/Event.java

@@ -4 +4 @@
 
 public class Event<T> {
-
+        
+        public static final Event<Object> STARTEVENT = new Event<Object>("START");
+        public static final Event<Object> ENDEVENT = new Event<Object>("END");
+        
         /**
          * <p>

trunk/EventBenchCore/src/de/ugoe/cs/eventbench/ppm/PredictionByPartialMatch.java

@@ -1 +1 @@
 package de.ugoe.cs.eventbench.ppm;
 
-import java.util.ArrayList;
 import java.util.LinkedHashSet;
 import java.util.LinkedList;
@@ -10 +9 @@
 import de.ugoe.cs.eventbench.data.Event;
 import de.ugoe.cs.eventbench.markov.IncompleteMemory;
-import de.ugoe.cs.util.console.Console;
 
 public class PredictionByPartialMatch {
         
-        private String initialSymbol = "GS";
-        private String endSymbol = "GE";
-        
         private int maxOrder = 3;
         
-        private Trie<String> trie;
-        
-        private Set<String> knownSymbols;
-        
-        private double probEscape = 0.2d; // TODO getter/setter - steering parameter!
-        
-        private Random r = new Random(); // TODO should be defined in the constructor
+        private Trie<Event<?>> trie;
+        
+        private Set<Event<?>> knownSymbols;
+        
+        private double probEscape;
+        
+        private final Random r;
+        
+        public PredictionByPartialMatch(Random r) {
+                this(r, 0.1);
+        }
+        
+        public PredictionByPartialMatch(Random r, double probEscape) {
+                this.r = r; // TODO defensive copy instead?
+                this.probEscape = probEscape;
+        }
+        
+        public void setProbEscape(double probEscape) {
+                this.probEscape = probEscape;
+        }
+        
+        public double getProbEscape() {
+                return probEscape;
+        }
         
         // the training is basically the generation of the trie
         public void train(List<List<Event<?>>> sequences) {
-                trie = new Trie<String>();
-                knownSymbols = new LinkedHashSet<String>();
-                knownSymbols.add(initialSymbol);
-                knownSymbols.add(endSymbol);
+                trie = new Trie<Event<?>>();
+                knownSymbols = new LinkedHashSet<Event<?>>();
+                knownSymbols.add(Event.STARTEVENT);
+                knownSymbols.add(Event.ENDEVENT);
                 
                 for(List<Event<?>> sequence : sequences) {
-                        List<String> stringSequence = new LinkedList<String>();
-                        stringSequence.add(initialSymbol);
-                        for( Event<?> event : sequence ) {
-                                stringSequence.add(event.getStandardId());
-                        }
-                        stringSequence.add(endSymbol);
+                        List<Event<?>> currentSequence = new LinkedList<Event<?>>(sequence); // defensive copy
+                        currentSequence.add(0, Event.STARTEVENT);
+                        currentSequence.add(Event.ENDEVENT);
                         
-                        trainStringTrie(stringSequence);
-                }
-        }
-        
-        private void trainStringTrie(List<String> sequence) {
-                knownSymbols = new LinkedHashSet<String>();             
-                IncompleteMemory<String> latestActions = new IncompleteMemory<String>(maxOrder);
+                        addToTrie(currentSequence);
+                }
+        }
+        
+        private void addToTrie(List<Event<?>> sequence) {
+                if( knownSymbols==null ) {
+                        knownSymbols = new LinkedHashSet<Event<?>>();
+                }
+                IncompleteMemory<Event<?>> latestActions = new IncompleteMemory<Event<?>>(maxOrder);
                 int i=0;
-                for(String currentAction : sequence) {
-                        String currentId = currentAction;
-                        latestActions.add(currentId);
-                        knownSymbols.add(currentId);
+                for(Event<?> currentEvent : sequence) {
+                        latestActions.add(currentEvent);
+                        knownSymbols.add(currentEvent);
                         i++;
                         if( i>=maxOrder ) {
@@ -65 +75 @@
         }
         
-        // TODO needs to be changed from String to <? extends Event>
-        public List<String> randomSequence() {
-                List<String> sequence = new LinkedList<String>();
-                
-                IncompleteMemory<String> context = new IncompleteMemory<String>(maxOrder-1);
-                context.add(initialSymbol);
-                sequence.add(initialSymbol);
-                
-                String currentState = initialSymbol;
-                
-                Console.println(currentState);
-                while(!endSymbol.equals(currentState)) {
+        public List<? extends Event<?>> randomSequence() {
+                List<Event<?>> sequence = new LinkedList<Event<?>>();
+                
+                IncompleteMemory<Event<?>> context = new IncompleteMemory<Event<?>>(maxOrder-1);
+                context.add(Event.STARTEVENT);
+                
+                Event<?> currentState = Event.STARTEVENT;
+                
+                boolean endFound = false;
+                
+                while(!endFound) {
                         double randVal = r.nextDouble();
                         double probSum = 0.0;
-                        List<String> currentContext = context.getLast(maxOrder);
-                        for( String symbol : knownSymbols ) {
+                        List<Event<?>> currentContext = context.getLast(maxOrder);
+                        for( Event<?> symbol : knownSymbols ) {
                                 probSum += getProbability(currentContext, symbol);
                                 if( probSum>=randVal ) {
-                                        context.add(symbol);
-                                        currentState = symbol;
-                                        sequence.add(currentState);
+                                        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);
+                                        }
                                         break;
                                 }
@@ -93 +106 @@
         }
                 
-        private double getProbability(List<String> context, String symbol) {
+        private double getProbability(List<Event<?>> context, Event<?> symbol) {
                 double result = 0.0d;
                 double resultCurrentContex = 0.0d;
                 double resultShorterContex = 0.0d;
                 
-                List<String> contextCopy = new LinkedList<String>(context); // defensive copy
-
-        
-                List<String> followers = trie.getFollowingSymbols(contextCopy); // \Sigma'
+                List<Event<?>> contextCopy = new LinkedList<Event<?>>(context); // defensive copy
+
+        
+                List<Event<?>> followers = trie.getFollowingSymbols(contextCopy); // \Sigma'
                 int sumCountFollowers = 0; // N(s\sigma')
-                for( String follower : followers ) {
+                for( Event<?> follower : followers ) {
                         sumCountFollowers += trie.getCount(contextCopy, follower);
                 }
@@ -130 +143 @@
         }
         
+        /*
         public void testStuff() {
                 // basically an inline unit test without assertions but manual observation
@@ -151 +165 @@
                 model.trainStringTrie(list);
                 model.trie.display();
-                Console.println("------------------------");
-                model.randomSequence();/*
-                Console.println("------------------------");
-                model.randomSequence();
-                Console.println("------------------------");
-                model.randomSequence();
-                Console.println("------------------------");*/
                 
                 List<String> context = new ArrayList<String>();
@@ -204 +211 @@
                 context.add("a");
                 Console.traceln(""+model.getProbability(context, "z"));
-        }
+        }*/
 }