InferenceEngine.html

InferenceEngine.java

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package blog;

import java.util.*;
import java.lang.reflect.*;

import common.Util;

Abstract class representing a BLOG inference engine. Its central method is answerQueries, which records answers to a list of queries (specified with the setQueries method) given some evidence (specified with the setEvidence method). If the inference algorithm is randomized, repeated calls to answerQueries may yield different results.

A concrete subclass of InferenceEngine should have a constructor with two arguments, of types blog.Model and java.util.Properties. The properties argument specifies configuration parameters for the inference engine; it may be ignored if the engine has no such parameters.


public abstract class InferenceEngine {

Returns a new InferenceEngine object for the given BLOG model, with properties specified by the given Properties table. In particular, the InferenceEngine subclass is specified by the engineClass property (the default is blog.SamplingEngine).


    public static InferenceEngine constructEngine(Model model, 
						  Properties properties) {
	String className = properties.getProperty("engineClass", 
						  "blog.SamplingEngine");
	System.out.println("Constructing inference engine of class " 
			   + className);

	try {
	    Class engineClass = Class.forName(className);
	    Class[] paramTypes = {Model.class, Properties.class};
	    Constructor constructor = engineClass.getConstructor(paramTypes);
	    
	    Object[] args = {model, properties};
	    return (InferenceEngine) constructor.newInstance(args);
	} catch (Exception e) {
	    Util.fatalError(e);
	}

	return null;
    }

Creates a new inference engine for the given BLOG model.


    public InferenceEngine(Model model) {
	this.model = model;
    }

Sets the evidence to be conditioned on in the next call to answerQueries.


    public void setEvidence(Evidence evidence) {
	this.evidence = evidence;
    }

Sets the queries to be answered in the next call to answerQueries.

Parameters:

queries - List of Query objects


    public void setQueries(List queries) {
	this.queries.clear();
	this.queries.addAll(queries);
    }

Computes the answers to the specified queries given the specified evidence. Records the answers by calling the appropriate methods (e.g., updateStats) on the specified Query objects.


    public abstract void answerQueries();

The BLOG model on which this engine performs inference.


    protected Model model;

The evidence set by the last call to setEvidence, or null if setEvidence has not been called.


    protected Evidence evidence = null;

List of Query objects specified by the last call to setQueries. This list is empty if setQueries has not been called.


    protected List queries = new ArrayList();
}

This file was generated on Tue Jun 08 17:53:36 PDT 2010 from file InferenceEngine.java
by the ilog.language.tools.Hilite Java tool written by Hassan Aït-Kaci