|
<< Click to Display Table of Contents >> Navigation: Tutorials > Tutorial 5: Inference in an Influence Diagram > Tutorial5.java |
package tutorials;
import smile.*;
// Tutorial5 loads the XDSL file created by Tutorial4,
// then performs the series of inference calls,
// changing evidence each time.
public class Tutorial5 {
public static void run() {
System.out.println("Starting Tutorial5...");
Network net = new Network();
net.readFile("tutorial4.xdsl");
System.out.println("No evidence set.");
net.updateBeliefs();
printFinancialGain(net);
System.out.println("Setting Forecast=Good.");
changeEvidenceAndUpdate(net, "Forecast", "Good");
System.out.println("Adding Economy=Up");
changeEvidenceAndUpdate(net, "Economy", "Up");
System.out.println("Tutorial5 complete.");
}
static void changeEvidenceAndUpdate(
Network net, String nodeId, String outcomeId) {
if (outcomeId != null) {
net.setEvidence(nodeId, outcomeId);
} else {
net.clearEvidence(nodeId);
}
net.updateBeliefs();
printFinancialGain(net);
}
static void printFinancialGain(Network net) {
double[] expectedUtility = net.getNodeValue("Gain");
int[] utilParents = net.getValueIndexingParents("Gain");
printGainMatrix(net, expectedUtility, utilParents);
}
static void printGainMatrix(Network net, double[] mtx, int[] parents) {
int dimCount = 1 + parents.length;
int[] dimSizes = new int[dimCount];
for (int i = 0; i < dimCount - 1; i ++) {
dimSizes[i] = net.getOutcomeCount(parents[i]);
}
dimSizes[dimSizes.length - 1] = 1;
int[] coords = new int[dimCount];
for (int elemIdx = 0; elemIdx < mtx.length; elemIdx ++) {
indexToCoords(elemIdx, dimSizes, coords);
System.out.print(" Utility(");
if (dimCount > 1)
{
for (int parentIdx = 0; parentIdx < parents.length; parentIdx++)
{
if (parentIdx > 0) System.out.print(",");
int parentHandle = parents[parentIdx];
System.out.printf("%s=%s",
net.getNodeId(parentHandle),
net.getOutcomeId(parentHandle, coords[parentIdx]));
}
}
System.out.printf(")=%f\n", mtx[elemIdx]);
}
System.out.println();
}
static void indexToCoords(int index, int[] dimSizes, int[] coords) {
int prod = 1;
for (int i = dimSizes.length - 1; i >= 0; i --) {
coords[i] = (index / prod) % dimSizes[i];
prod *= dimSizes[i];
}
}
}