HierarchicalUnaryRule.java

/**
 * 
 */
package edu.berkeley.nlp.PCFGLA;

import java.util.ArrayList;
import java.util.List;
import java.util.Random;

import edu.berkeley.nlp.util.ArrayUtil;
import edu.berkeley.nlp.util.Numberer;

/**
 * @author petrov
 *
 */
public class HierarchicalUnaryRule extends UnaryRule {

	private static final long serialVersionUID = 1L;

	public HierarchicalUnaryRule(HierarchicalUnaryRule b) {
		super(b);
		this.scoreHierarchy = new ArrayList<double[][]>();
		for (double[][] scores : b.scoreHierarchy){
			this.scoreHierarchy.add(ArrayUtil.clone(scores));
		}
		this.lastLevel = b.lastLevel;
		this.scores = null;
	}

	// assume for now that the rule being passed in is unsplit
	public HierarchicalUnaryRule(UnaryRule b) {
		super(b);
		this.scoreHierarchy = new ArrayList<double[][]>();
		double[][] scoreThisLevel = new double[1][1];
		scoreThisLevel[0][0] = Math.log(b.scores[0][0]);
		scoreHierarchy.add(scoreThisLevel);
		this.lastLevel = 0;
		this.scores = null;
	}


	/*
	 * new stuff below
	 */ 
	
  /**
	 * before: scores[childSubState][parentSubState] gives score for this rule
	 * now: have a hierarchy of refinements 
	 */
	
	List<double[][]> scoreHierarchy;
	public int lastLevel = -1;

	public void explicitlyComputeScores(int finalLevel, short[] newNumSubStates){
		int newMaxStates = (int)Math.pow(2,finalLevel+1);
		int newPStates = Math.min(newMaxStates, newNumSubStates[this.parentState]);
		int newCStates = Math.min(newMaxStates, newNumSubStates[this.childState]);

		newPStates = (this.parentState==0) ? 1 : newPStates;
		this.scores = new double[newCStates][newPStates];
		for (int level=0; level<=lastLevel; level++){
			double[][] scoresThisLevel = scoreHierarchy.get(level); 
			if (scoresThisLevel == null) continue;
			int divisorC = newCStates / scoresThisLevel.length;
			int divisorP = newPStates / scoresThisLevel[0].length;
			for (int child=0; child<newCStates; child++){
				for (int parent=0; parent<newPStates; parent++){
					this.scores[child][parent] += scoresThisLevel[child/divisorC][parent/divisorP];
				}
			}
		}
		for (int child=0; child<newCStates; child++){
			for (int parent=0; parent<newPStates; parent++){
				this.scores[child][parent] = Math.exp(scores[child][parent]);
			}
		}
	}
	
	public double[][] getLastLevel(){
		return this.scoreHierarchy.get(lastLevel);
	}
	  
	public HierarchicalUnaryRule splitRule(short[] numSubStates, short[] newNumSubStates, Random random, double randomness, boolean doNotNormalize, int mode) {
		// when splitting on parent, never split on ROOT, but otherwise split everything
		if (mode!=2) throw new Error("Can't split hiereachical rule in this mode!");

		int newMaxStates = (int)Math.pow(2,lastLevel+1);
		int newPStates = Math.min(newMaxStates, newNumSubStates[this.parentState]);
		int newCStates = Math.min(newMaxStates, newNumSubStates[this.childState]);

		if (parentState==0) newPStates = 1;
		double[][] newScores = new double[newCStates][newPStates];
		for (int child=0; child<newCStates; child++){
			for (int parent=0; parent<newPStates; parent++){
				newScores[child][parent] = random.nextDouble()/100.0;
			}
		}
		HierarchicalUnaryRule newRule = new HierarchicalUnaryRule(this);
		newRule.scoreHierarchy.add(newScores);
		newRule.lastLevel++;
		return newRule;
	}

	public int mergeRule() {
		double[][] scoresFinalLevel = scoreHierarchy.get(lastLevel);
		boolean allZero = true;
		for (int child=0; child<scoresFinalLevel.length; child++){
			for (int parent=0; parent<scoresFinalLevel[0].length; parent++){
				allZero = allZero && (scoresFinalLevel[child][parent] == 0.0);
			}
		}
		if (allZero) {
			scoresFinalLevel = null;
			scoreHierarchy.remove(lastLevel);
			lastLevel--;
			return 1;
		}
		return 0;
	}
	

  public String toString() {
    Numberer n = Numberer.getGlobalNumberer("tags");
    String cState = (String)n.object(childState);
    String pState = (String)n.object(parentState);
    if (scores==null) return pState+" -> "+cState+"\n";
    StringBuilder sb = new StringBuilder();
    sb.append(pState+" -> "+cState+"\n");
    sb.append(ArrayUtil.toString(scores)+"\n");
    for (double[][] s : scoreHierarchy){
    	sb.append(ArrayUtil.toString(s)+"\n");
    }
    sb.append("\n");
//    for (int cS=0; cS<scores.length; cS++){
//  		if (scores[cS]==null) continue;
//  		for (int pS=0; pS<scores[cS].length; pS++){
//  			double p = scores[cS][pS]; 
//  			if (p>0)
//  				sb.append(pState+"_"+pS+ " -> " + cState+"_"+cS +" "+p+"\n");
//  		}
//    }
    return sb.toString();
  }
  
  public int countNonZeroFeatures(){
  	int total = 0;
		for (int level=0; level<=lastLevel; level++){
			double[][] scoresThisLevel = scoreHierarchy.get(level); 
			if (scoresThisLevel == null) continue;
			for (int child=0; child<scoresThisLevel.length; child++){
				for (int parent=0; parent<scoresThisLevel[0].length; parent++){
					if (scoresThisLevel[child][parent]!=0) total++;
				}
			}
		}
		return total;
  }

}