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package tutorials;
import smile.*;
// Tutorial2 loads the XDSL file created by Tutorial1,
// then performs the series of inference calls,
// changing evidence each time.
public class Tutorial2 {
public static void run() {
System.out.println("Starting Tutorial2...");
Network net = new Network();
// load the network created by Tutorial1
net.readFile("tutorial1.xdsl");
System.out.println("Posteriors with no evidence set:");
net.updateBeliefs();
printAllPosteriors(net);
System.out.println("Setting Forecast=Good.");
changeEvidenceAndUpdate(net, "Forecast", "Good");
System.out.println("Adding Economy=Up.");
changeEvidenceAndUpdate(net, "Economy", "Up");
System.out.println("Changing Forecast to Poor, keeping Economy=Up.");
changeEvidenceAndUpdate(net, "Forecast", "Poor");
System.out.println(
"Removing evidence from Economy, keeping Forecast=Poor.");
changeEvidenceAndUpdate(net, "Economy", null);
System.out.println("Tutorial2 complete.");
}
private static void printPosteriors(Network net, int nodeHandle) {
String nodeId = net.getNodeId(nodeHandle);
if (net.isEvidence(nodeHandle)) {
System.out.printf("%s has evidence set (%s)\n",
nodeId,
net.getOutcomeId(nodeHandle, net.getEvidence(nodeHandle)));
} else {
double[] posteriors = net.getNodeValue(nodeHandle);
for (int i = 0; i < posteriors.length; i ++) {
System.out.printf("P(%s=%s)=%f\n",
nodeId,
net.getOutcomeId(nodeHandle, i),
posteriors[i]);
}
}
}
private static void printAllPosteriors(Network net) {
for (int h = net.getFirstNode(); h >= 0; h = net.getNextNode(h)) {
printPosteriors(net, h);
}
System.out.println();
}
private static void changeEvidenceAndUpdate(
Network net, String nodeId, String outcomeId) {
if (outcomeId != null) {
net.setEvidence(nodeId, outcomeId);
} else {
net.clearEvidence(nodeId);
}
net.updateBeliefs();
printAllPosteriors(net);
}
}