/**
* Compare the target segments to the 'otherSegments', and update the classifier by sum_x
* [delta*x], for each example x corresponding to a target segment that's not in otherSegments.
*/
private int compareSegmentsAndIncrement(
ExampleSchema schema,
Segmentation segments,
Segmentation otherSegments,
Hyperplane[] accum,
double delta,
CandidateSegmentGroup g) {
int errors = 0;
// first, work out the name of the previous class for each segment
Map<Segment, String> map = previousClassMap(segments, schema);
Map<Segment, String> otherMap = previousClassMap(otherSegments, schema);
String[] history = new String[1];
for (Iterator<Segment> j = segments.iterator(); j.hasNext(); ) {
Segmentation.Segment seg = j.next();
String previousClass = map.get(seg);
if (seg.lo >= 0
&& (!otherSegments.contains(seg) || !otherMap.get(seg).equals(previousClass))) {
errors++;
history[0] = previousClass;
Instance instance =
new InstanceFromSequence(g.getSubsequenceExample(seg.lo, seg.hi), history);
if (DEBUG)
log.debug(
"class "
+ schema.getClassName(seg.y)
+ " update "
+ delta
+ " for: "
+ instance.getSource());
accum[seg.y].increment(instance, delta);
}
}
return errors;
}
/** Analogous to binaryFeatureSet */
private Set<Feature> numericFeatureSet(int start, int end, Instance otherInstance) {
Set<Feature> s = new HashSet<Feature>();
for (int i = start; i < end; i++) {
addAll(s, unitInstance[i].numericFeatureIterator());
}
if (otherInstance != null) addAll(s, otherInstance.numericFeatureIterator());
return s;
}
@Override
public Explanation getExplanation(Instance instance) {
Explanation.Node top = new Explanation.Node("DecisionTree Explanation");
if (instance.getWeight(test) >= threshold) {
Explanation.Node node =
new Explanation.Node(test + "=" + instance.getWeight(test) + ">=" + threshold);
Explanation.Node childEx = ifTrue.getExplanation(instance).getTopNode();
node.add(childEx);
top.add(node);
} else {
Explanation.Node node =
new Explanation.Node(test + "=" + instance.getWeight(test) + "<" + threshold);
Explanation.Node childEx = ifFalse.getExplanation(instance).getTopNode();
node.add(childEx);
top.add(node);
}
Explanation ex = new Explanation(top);
return ex;
}
@Override
public String explain(Instance instance) {
if (instance.getWeight(test) >= threshold) {
return test
+ "="
+ instance.getWeight(test)
+ ">="
+ threshold
+ "\n"
+ ifTrue.explain(instance);
} else {
return test
+ "="
+ instance.getWeight(test)
+ "<"
+ threshold
+ "\n"
+ ifFalse.explain(instance);
}
}
public Delta(FeatureFactory factory, int start, int end, Instance segmentInstance) {
for (Iterator<Feature> i = featureSet(start, end, segmentInstance).iterator();
i.hasNext(); ) {
Feature f = i.next();
// replace the feature with its canonical version, so
// that variant versions are not stored in the
// deltaWeight, zeroWeights hash tables
f = factory.getFeature(f);
double segmentWeight = segmentInstance.getWeight(f);
if (segmentWeight == 0) zeroWeights.add(f);
else {
double sumWeight = getSumWeight(start, end, f);
if (segmentWeight != sumWeight) deltaWeight.put(f, segmentWeight - sumWeight);
}
}
/*
System.out.println("segmentInstance: "+segmentInstance);
System.out.println("deltaInstance: "+new DeltaInstance(start,end,this,
segmentInstance.getSource(),
segmentInstance.getSubpopulationId()));
*/
}
@Override
public double score(Instance instance) {
if (instance.getWeight(test) >= threshold) return ifTrue.score(instance);
else return ifFalse.score(instance);
}