EnumerationAsk.java

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package edu.tum.cs.bayesnets.inference;

import edu.ksu.cis.bnj.ver3.core.Domain;
import edu.tum.cs.bayesnets.core.BeliefNetworkEx;
import edu.tum.cs.util.Stopwatch;

public class EnumerationAsk extends Sampler {
        int[] nodeOrder;
        int numPathsPruned;
        double numWorldsPruned, numWorldsCounted;
        Stopwatch timer;
        double numTotalWorlds;
        
        public EnumerationAsk(BeliefNetworkEx bn) throws Exception {
                super(bn);
                nodeOrder = bn.getTopologicalOrder();
                numTotalWorlds = bn.getNumWorlds();
        }
        
        public SampledDistribution _infer() throws Exception {
                Stopwatch sw = new Stopwatch();
                numPathsPruned = 0;
                numWorldsPruned = numWorldsCounted = 0;
                createDistribution();
                if(verbose) out.printf("enumerating %s worlds...\n", numTotalWorlds);
                sw.start();
                WeightedSample s = new WeightedSample(bn);
                timer = new Stopwatch();
                timer.start();          
                enumerateWorlds(s, nodeOrder, evidenceDomainIndices, 0, 1); 
                sw.stop();
                report(String.format("\ntime taken: %.2fs (%d worlds enumerated, %d paths pruned)\n", sw.getElapsedTimeSecs(), dist.steps, numPathsPruned));
                return dist;
        }
        
        public void enumerateWorlds(WeightedSample s, int[] nodeOrder, int[] evidenceDomainIndices, int i, double combinationsHandled) throws Exception {
                //out.printf("enum %s, domain size = %d\n", nodes[nodeOrder[i]].getName(), nodes[nodeOrder[i]].getDomain().getOrder());
                // status messages
                if(timer.getElapsedTimeSecs() > 1) {
                        double numDone = numWorldsCounted+numWorldsPruned;
                        if(verbose) out.printf(" ~ %.4f%% done (%s worlds handled, %d paths pruned)\r", 100.0*numDone/numTotalWorlds, numDone, numPathsPruned);  
                        timer = new Stopwatch();
                        timer.start();                  
                }
                // if we have completed the world, we are done and can add the world as a sample
                if(i == nodes.length) {
                        //out.println("counting sample");
                        addSample(s);
                        numWorldsCounted++;
                        return;
                }
                // otherwise continue            
                int nodeIdx = nodeOrder[i];
                combinationsHandled *= nodes[nodeOrder[i]].getDomain().getOrder();
                int domainIdx = evidenceDomainIndices[nodeIdx];
                // for evidence nodes, adjust the weight
                if(domainIdx >= 0) { 
                        s.nodeDomainIndices[nodeIdx] = domainIdx;
                        double prob = getCPTProbability(nodes[nodeIdx], s.nodeDomainIndices);
                        s.weight *= prob;
                        if(prob == 0.0) { // we have reached zero, so we can save us the trouble of further ramifications
                                //out.println("zero reached");
                                numPathsPruned++;
                                numWorldsPruned += numTotalWorlds / combinationsHandled; 
                                return;
                        }                       
                        enumerateWorlds(s, nodeOrder, evidenceDomainIndices, i+1, combinationsHandled);
                } 
                // for non-evidence nodes, consider all settings
                else {
                        Domain d = nodes[nodeIdx].getDomain();
                        int order = d.getOrder();
                        //out.println("  enumerating all " + order + " cases for " + nodes[nodeIdx].getName());                 
                        double weight = s.weight;
                        for(int j = 0; j < order; j++) { 
                                s.nodeDomainIndices[nodeIdx] = j;
                                double prob = getCPTProbability(nodes[nodeIdx], s.nodeDomainIndices);
                                if(prob == 0.0) {
                                        //out.println("zero reached");
                                        numPathsPruned++;
                                        numWorldsPruned += numTotalWorlds / combinationsHandled;
                                        continue;
                                }
                                s.weight = weight * prob;
                                enumerateWorlds(s, nodeOrder, evidenceDomainIndices, i+1, combinationsHandled);
                        }
                }                       
        }
}

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srldb
Author(s): Dominik Jain, Stefan Waldherr, Moritz Tenorth
autogenerated on Fri Jan 11 09:58:29 2013