76 lines
1.9 KiB
Java
Executable File
76 lines
1.9 KiB
Java
Executable File
//Copyright (c) 2016 Yarong Zeng, NUDT.
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package com.ow2.rec.util;
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import java.util.HashSet;
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import java.util.LinkedList;
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import java.util.List;
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import java.util.Set;
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public class SimilarityCounter {
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//两个文本结合 以及各自个各个分量的权重的倒数
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public static float countSimilarity(List<String>prj,int[]prjWeight,List<String>tag,int[]tagWeight){
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//如果没有共同的元素就直接返回0
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List<String> prjTmp = new LinkedList<String>(prj);
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prjTmp.retainAll(tag);
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if(prjTmp.size() == 0){
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return 0;
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}
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//如果完全匹配就直接返回1
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if(prj.containsAll(tag) && tag.containsAll(prj))
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return 1;
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//如果项目名称为单个字母，直接返回0
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if(prj.size() == 1 && prj.get(0).length() == 1){
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return 0;
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}
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Set<String> union= new HashSet<String>();//此集合用于存储项目和标签匹配时他们的原子性元素的并集
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union.addAll(prj);
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union.addAll(tag);
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//生成两个向量
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float prjVector[] = new float[union.size()];
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float tagVector[] = new float[union.size()];
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int i = 0;
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for(String item : union){
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if(prj.contains(item))
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prjVector[i] = 1.0F / prjWeight[prj.indexOf(item)];
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if(tag.contains(item))
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tagVector[i] = 1.0F / tagWeight[tag.indexOf(item)];
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i++;
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}
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//两个向量的点积
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float dotMulti = 0,absPrjUnSqrt = 0, absTagUnSqrt =0;
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for(i = 0; i< prjVector.length; i++){
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dotMulti += prjVector[i] * tagVector[i];
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absPrjUnSqrt += prjVector[i] * prjVector[i];
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absTagUnSqrt += tagVector[i] * tagVector[i];
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}
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float absPrj = 0, absTag =0;
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absPrj = (float) Math.sqrt(absPrjUnSqrt );
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absTag = (float) Math.sqrt(absTagUnSqrt );
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return formatFloat(dotMulti / ( absPrj * absTag),3);
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}
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private static float formatFloat(float f,int num){
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int base = (int) Math.pow(10,num);
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return (float) (Math.round(f * base))/base;
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}
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}
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