From 406f8775c704df9e288ca2896b2b596c49538178 Mon Sep 17 00:00:00 2001
From: desaicwtf <desaicwtf@ec762483-ff6d-05da-a07a-a48fb63a330f>
Date: Fri, 9 Jul 2010 20:55:36 +0000
Subject: context->phrase

git-svn-id: https://ws10smt.googlecode.com/svn/trunk@211 ec762483-ff6d-05da-a07a-a48fb63a330f
---
 .../prjava/src/phrase/C2F.java                     | 205 ++++++++++++++++++++-
 1 file changed, 200 insertions(+), 5 deletions(-)

diff --git a/gi/posterior-regularisation/prjava/src/phrase/C2F.java b/gi/posterior-regularisation/prjava/src/phrase/C2F.java
index 2646d961..63dad2ab 100644
--- a/gi/posterior-regularisation/prjava/src/phrase/C2F.java
+++ b/gi/posterior-regularisation/prjava/src/phrase/C2F.java
@@ -1,17 +1,212 @@
 package phrase;
+
+import gnu.trove.TIntArrayList;
+
+import io.FileUtil;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.PrintStream;
+import java.util.Arrays;
+import java.util.List;
+
+import phrase.Corpus.Edge;
+
 /**
  * @brief context generates phrase
  * @author desaic
  *
  */
 public class C2F {
-
-	/**
-	 * @param args
+	public int K;
+	private int n_words, n_contexts, n_positions;
+	public Corpus c;
+	
+	/**@brief
+	 *  emit[tag][position][word] = p(word | tag, position in phrase)
+	 */
+	private double emit[][][];
+	/**@brief
+	 *  pi[context][tag] = p(tag | context)
+	 */
+	private double pi[][];
+	
+	public C2F(int numCluster, Corpus corpus){
+		K=numCluster;
+		c=corpus;
+		n_words=c.getNumWords();
+		n_contexts=c.getNumContexts();
+		
+		//number of words in a phrase to be considered
+		//currently the first and last word
+		//if the phrase has length 1 
+		//use the same word for two positions
+		n_positions=2;
+		
+		emit=new double [K][n_positions][n_words];
+		pi=new double[n_contexts][K];
+		
+		for(double [][]i:emit){
+			for(double []j:i){
+				arr.F.randomise(j);
+			}
+		}
+		
+		for(double []j:pi){
+			arr.F.randomise(j);
+		}
+	}
+	
+	/**@brief test
+	 * 
 	 */
-	public static void main(String[] args) {
-		// TODO Auto-generated method stub
+	public static void main(String args[]){
+		String in="../pdata/canned.con";
+		String out="../pdata/posterior.out";
+		int numCluster=5;
+		Corpus corpus = null;
+		File infile = new File(in);
+		try {
+			System.out.println("Reading concordance from " + infile);
+			corpus = Corpus.readFromFile(FileUtil.reader(infile));
+			corpus.printStats(System.out);
+		} catch (IOException e) {
+			System.err.println("Failed to open input file: " + infile);
+			e.printStackTrace();
+			System.exit(1);
+		}
+		
+		C2F c2f=new C2F(numCluster,corpus);
+		int iter=20;
+		double llh=0;
+		for(int i=0;i<iter;i++){
+			llh=c2f.EM();
+			System.out.println("Iter"+i+", llh: "+llh);
+		}
+		
+		File outfile = new File (out);
+		try {
+			PrintStream ps = FileUtil.printstream(outfile);
+			c2f.displayPosterior(ps);
+			ps.println();
+			c2f.displayModelParam(ps);
+			ps.close();
+		} catch (IOException e) {
+			System.err.println("Failed to open output file: " + outfile);
+			e.printStackTrace();
+			System.exit(1);
+		}
+		
+	}
+	
+	public double EM(){
+		double [][][]exp_emit=new double [K][n_positions][n_words];
+		double [][]exp_pi=new double[n_contexts][K];
+		
+		double loglikelihood=0;
+		
+		//E
+		for(int context=0; context< n_contexts; context++){
+			
+			List<Edge> contexts = c.getEdgesForContext(context);
+
+			for (int ctx=0; ctx<contexts.size(); ctx++){
+				Edge edge = contexts.get(ctx);
+				double p[]=posterior(edge);
+				double z = arr.F.l1norm(p);
+				assert z > 0;
+				loglikelihood += edge.getCount() * Math.log(z);
+				arr.F.l1normalize(p);
+				
+				int count = edge.getCount();
+				//increment expected count
+				TIntArrayList phrase= edge.getPhrase();
+				for(int tag=0;tag<K;tag++){
+
+					exp_emit[tag][0][phrase.get(0)]+=p[tag]*count;
+					exp_emit[tag][1][phrase.get(phrase.size()-1)]+=p[tag]*count;
+					
+					exp_pi[context][tag]+=p[tag]*count;
+				}
+			}
+		}
+		
+		//System.out.println("Log likelihood: "+loglikelihood);
+		
+		//M
+		for(double [][]i:exp_emit){
+			for(double []j:i){
+				arr.F.l1normalize(j);
+			}
+		}
+		
+		emit=exp_emit;
+		
+		for(double []j:exp_pi){
+			arr.F.l1normalize(j);
+		}
+		
+		pi=exp_pi;
+		
+		return loglikelihood;
+	}
 
+	public double[] posterior(Corpus.Edge edge) 
+	{
+		double[] prob=Arrays.copyOf(pi[edge.getPhraseId()], K);
+		
+		TIntArrayList phrase = edge.getPhrase();
+		for(int tag=0;tag<K;tag++)
+			prob[tag]*=emit[tag][0][phrase.get(0)]
+			                        *emit[tag][1][phrase.get(phrase.size()-1)];
+		return prob;
 	}
 
+	public void displayPosterior(PrintStream ps)
+	{	
+		for (Edge edge : c.getEdges())
+		{
+			double probs[] = posterior(edge);
+			arr.F.l1normalize(probs);
+
+			// emit phrase
+			ps.print(edge.getPhraseString());
+			ps.print("\t");
+			ps.print(edge.getContextString(true));
+			int t=arr.F.argmax(probs);
+			ps.println(" ||| C=" + t);
+		}
+	}
+	
+	public void displayModelParam(PrintStream ps)
+	{
+		final double EPS = 1e-6;
+		
+		ps.println("P(tag|context)");
+		for (int i = 0; i < n_contexts; ++i)
+		{
+			ps.print(c.getContext(i));
+			for(int j=0;j<pi[i].length;j++){
+				if (pi[i][j] > EPS)
+					ps.print("\t" + j + ": " + pi[i][j]);
+			}
+			ps.println();
+		}
+		
+		ps.println("P(word|tag,position)");
+		for (int i = 0; i < K; ++i)
+		{
+			for(int position=0;position<n_positions;position++){
+				ps.println("tag " + i + " position " + position);
+				for(int word=0;word<emit[i][position].length;word++){
+					if (emit[i][position][word] > EPS)
+						ps.print(c.getWord(word)+"="+emit[i][position][word]+"\t");
+				}
+				ps.println();
+			}
+			ps.println();
+		}
+		
+	}
+	
 }
-- 
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