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package tutorials;
import smile.*;
// Tutorial8 loads continuous model from the XDSL file written by Tutorial7,
// then adds discrete nodes to create a hybrid model. Inference is performed
// and model is saved to disk.
public class Tutorial8 {
public static void run() {
System.out.println("Starting Tutorial8...");
Network net = new Network();
net.readFile("tutorial7.xdsl");
createCptNode(
net, "zone", "Climate Zone",
new String[] { "Temperate", "Desert" },
60, 20);
int toaHandle = net.getNode("toa");
net.setNodeEquation(toaHandle, "toa=If(zone=\"Desert\",Normal(22,5),Normal(11,10))");
int perceivedHandle = createCptNode(
net, "perceived", "Perceived Temperature",
new String[] { "Hot", "Warm", "Cold" },
60, 300);
net.addArc(toaHandle, perceivedHandle);
double[] perceivedProbs = new double[] {
0, // P(perceived=Hot |toa in -10..0)
0.02, // P(perceived=Warm|toa in -10..0)
0.98, // P(perceived=Cold|toa in -10..0)
0.05, // P(perceived=Hot |toa in 0..10)
0.15, // P(perceived=Warm|toa in 0..10)
0.80, // P(perceived=Cold|toa in 0..10)
0.10, // P(perceived=Hot |toa in 10..20)
0.80, // P(perceived=Warm|toa in 10..20)
0.10, // P(perceived=Cold|toa in 10..20)
0.80, // P(perceived=Hot |toa in 20..30)
0.15, // P(perceived=Warm|toa in 20..30)
0.05, // P(perceived=Cold|toa in 20..30)
0.98, // P(perceived=Hot |toa in 30..40)
0.02, // P(perceived=Warm|toa in 30..40)
0 // P(perceived=Cold|toa in 30..40)
};
net.setNodeDefinition(perceivedHandle, perceivedProbs);
net.setEvidence("zone", "Temperate");
System.out.println("Results in temperate zone:");
updateAndShowStats(net);
net.setEvidence("zone", "Desert");
System.out.println("Results in desert zone:\n");
updateAndShowStats(net);
net.writeFile("tutorial8.xdsl");
System.out.println("Tutorial8 complete: Network written to tutorial8.xdsl");
}
static void showStats(Network net, int nodeHandle) {
String nodeId = net.getNodeId(nodeHandle);
if (net.isEvidence(nodeHandle)) {
double v = net.getContEvidence(nodeHandle);
System.out.printf("%s has evidence set (%g)\n", nodeId, v);
return;
}
if (net.isValueDiscretized(nodeHandle)) {
System.out.printf("%s is discretized.\n", nodeId);
DiscretizationInterval[] iv =
net.getNodeEquationDiscretization(nodeHandle);
double[] bounds = net.getNodeEquationBounds(nodeHandle);
double[] discBeliefs = net.getNodeValue(nodeHandle);
double lo = bounds[0];
for (int i = 0; i < discBeliefs.length; i++) {
double hi = iv[i].boundary;
System.out.printf(
"\tP(%s in %g..%g)=%g\n", nodeId, lo, hi, discBeliefs[i]);
lo = hi;
}
} else {
double[] stats = net.getNodeSampleStats(nodeHandle);
System.out.printf("%s: mean=%g stddev=%g min=%g max=%g\n",
nodeId, stats[0], stats[1], stats[2], stats[3]);
}
}
static void updateAndShowStats(Network net) {
net.updateBeliefs();
for (int h = net.getFirstNode(); h >= 0; h = net.getNextNode(h))
{
if (net.getNodeType(h) == Network.NodeType.EQUATION) {
showStats(net, h);
}
}
System.out.println();
}
private static int createCptNode(
Network net, String id, String name,
String[] outcomes, int xPos, int yPos) {
int handle = net.addNode(Network.NodeType.CPT, id);
net.setNodeName(handle, name);
net.setNodePosition(handle, xPos, yPos, 85, 55);
int initialOutcomeCount = net.getOutcomeCount(handle);
for (int i = 0; i < initialOutcomeCount; i ++) {
net.setOutcomeId(handle, i, outcomes[i]);
}
for (int i = initialOutcomeCount; i < outcomes.length; i ++) {
net.addOutcome(handle, outcomes[i]);
}
return handle;
}
}