Java tutorial
/******************************************************************************* * Copyright 2015-2016 - CNRS (Centre National de Recherche Scientifique) * * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. * *******************************************************************************/ /* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright 2, 2015nership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */ package eu.project.ttc.models; import java.util.Iterator; import java.util.Map; import org.apache.commons.lang3.mutable.MutableDouble; import com.google.common.collect.Maps; import eu.project.ttc.metrics.AssociationRate; /** * * An index (often called cross table) that helps to compute * the association rate of two terms, i.e. their amount of co-occurrency * in the corpus. * * @author Damien Cram * */ public class CrossTable { /** * The term index of the corpus */ private TermIndex termIndex; private Map<Term, MutableDouble> aPlusB; private Map<Term, MutableDouble> aPlusC; private int totalCoOccurrences; // private int totalFrequency; /** * * Constructs this cross table with a term index and inits the table * with all co-occurrences of the term index's terms. This init process is * based on terms' context vectors, which must be computed before * invoking this constructor. * * @see Term#getContextVector() * @throws NullPointerException * if terms' context vectors are not already computed * @param termIndex * The term index of the corpus * @throws NullPointerException * when the context vectors of term index terms are not */ public CrossTable(TermIndex termIndex) { super(); this.termIndex = termIndex; init(); } private void init() { this.aPlusB = Maps.newHashMap(); this.aPlusC = Maps.newHashMap(); this.totalCoOccurrences = 0; // this.totalFrequency = 0; Term term; for (Iterator<Term> it1 = this.termIndex.getTerms().iterator(); it1.hasNext();) { term = it1.next(); // this.totalFrequency++; if (!term.isContextVectorComputed()) continue; ContextVector context = term.getContextVector(); for (ContextVector.Entry entry : context.getEntries()) { this.totalCoOccurrences += entry.getNbCooccs(); getScoreFromMap(this.aPlusB, term).add(entry.getNbCooccs()); getScoreFromMap(this.aPlusC, entry.getCoTerm()).add(term.getFrequency()); } } } private MutableDouble getScoreFromMap(Map<Term, MutableDouble> aScoreMap, Term key) { if (aScoreMap.get(key) == null) aScoreMap.put(key, new MutableDouble(0)); return aScoreMap.get(key); } /** * * Computes coefficients a, b, c and d (available) and computes the association * rate based on these coefficients. * * These coefficients are made available through the not-thread safe methods <code>#getLastX()</code>. * * @see #getLastA() * @see #getLastB() * @see #getLastC() * @see #getLastD() * * @param rate * the association rate measure * @param x * the base term * @param y * the co term * @return * the association rate */ public double computeRate(AssociationRate rate, Term x, Term y) { // A = (x & y) int a = (int) x.getContextVector().getNbCooccs(y); // B = (x & not(y)) MutableDouble a_plus_b = this.aPlusB.get(x); int b = a_plus_b == null ? 0 : a_plus_b.intValue() - a; // int b = x.getFrequency() - a; // C = (not(x) & y) MutableDouble a_plus_c = this.aPlusB.get(y); int c = a_plus_c == null ? 0 : a_plus_c.intValue() - a; // int c = y.getFrequency() - a; // D = (not(x) & not(y)) int d = this.totalCoOccurrences - a - b - c; // int d = this.totalFrequency - a - b - c; // for DEBUG purpose only lastA = a; lastB = b; lastC = c; lastD = d; // END DEBUG final double value = rate.getValue(a, b, c, d); return value; } private int lastA; private int lastB; private int lastC; private int lastD; /** * The number of times <code>coTerm</code> id a co-occurrence of <code>term</code> * * WARNING : not thread safe ! * * @return */ public int getLastA() { return lastA; } /** * The number of times a co-occurrence of <code>term</code> is not <code>coTerm</code> * * WARNING : not thread safe ! * * @return */ public int getLastB() { return lastB; } /** * The number of times <code>coTerm</code> is a co-occurrence of another term * than <code>term</code>. * * WARNING : not thread safe ! * * @return */ public int getLastC() { return lastC; } /** * The number of times neither <code>term</code> nor <code>coTerm</code> is a co-occurrence of something else * * WARNING : not thread safe ! * * @return */ public int getLastD() { return lastD; } }