[13] | 1 | package de.ugoe.cs.eventbench.models;
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[1] | 2 |
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[5] | 3 | import java.util.LinkedList;
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[1] | 4 | import java.util.List;
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| 5 | import java.util.Random;
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| 6 |
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| 7 | import de.ugoe.cs.eventbench.data.Event;
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| 8 |
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[12] | 9 | public class PredictionByPartialMatch extends TrieBasedModel {
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[1] | 10 |
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[12] | 11 | double probEscape;
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[1] | 12 |
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[16] | 13 | public PredictionByPartialMatch(int markovOrder, Random r) {
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| 14 | this(markovOrder, r, 0.1);
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[7] | 15 | }
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| 16 |
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[16] | 17 | public PredictionByPartialMatch(int markovOrder, Random r, double probEscape) {
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| 18 | super(markovOrder, r);
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[7] | 19 | this.probEscape = probEscape;
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| 20 | }
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| 21 |
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| 22 | public void setProbEscape(double probEscape) {
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| 23 | this.probEscape = probEscape;
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| 24 | }
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| 25 |
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| 26 | public double getProbEscape() {
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| 27 | return probEscape;
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| 28 | }
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| 29 |
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[12] | 30 | @Override
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| 31 | protected double getProbability(List<Event<?>> context, Event<?> symbol) {
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[6] | 32 | double result = 0.0d;
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| 33 | double resultCurrentContex = 0.0d;
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| 34 | double resultShorterContex = 0.0d;
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| 35 |
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[7] | 36 | List<Event<?>> contextCopy = new LinkedList<Event<?>>(context); // defensive copy
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[6] | 37 |
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| 38 |
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[7] | 39 | List<Event<?>> followers = trie.getFollowingSymbols(contextCopy); // \Sigma'
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[6] | 40 | int sumCountFollowers = 0; // N(s\sigma')
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[7] | 41 | for( Event<?> follower : followers ) {
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[6] | 42 | sumCountFollowers += trie.getCount(contextCopy, follower);
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| 43 | }
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| 44 |
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| 45 | int countSymbol = trie.getCount(contextCopy, symbol); // N(s\sigma)
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| 46 | if( contextCopy.size()==0 ) {
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| 47 | resultCurrentContex = ((double) countSymbol) / sumCountFollowers;
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| 48 | } else {
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| 49 | resultCurrentContex = ((double) countSymbol / sumCountFollowers)*(1-probEscape);
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| 50 | contextCopy.remove(0);
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| 51 | double probSuffix = getProbability(contextCopy, symbol);
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| 52 | if( followers.size()==0 ) {
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| 53 | resultShorterContex = probSuffix;
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| 54 | } else {
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| 55 | resultShorterContex = probEscape*probSuffix;
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| 56 | }
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| 57 | }
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| 58 | result = resultCurrentContex+resultShorterContex;
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| 59 |
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| 60 | return result;
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| 61 | }
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[1] | 62 | }
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