public void setModelContext(InstancesHeader ih) {
if ((ih != null) && (ih.classIndex() < 0)) {
throw new IllegalArgumentException("Context for a classifier must include a class to learn");
}
if (trainingHasStarted()
&& (this.modelContext != null)
&& ((ih == null) || !contextIsCompatible(this.modelContext, ih))) {
throw new IllegalArgumentException("New context is not compatible with existing model");
}
this.modelContext = ih;
}
// originalContext notnull
// newContext notnull
public static boolean contextIsCompatible(
InstancesHeader originalContext, InstancesHeader newContext) {
// rule 1: num classes can increase but never decrease
// rule 2: num attributes can increase but never decrease
// rule 3: num nominal attribute values can increase but never decrease
// rule 4: attribute types must stay in the same order (although class
// can
// move; is always skipped over)
// attribute names are free to change, but should always still represent
// the original attributes
if (newContext.numClasses() < originalContext.numClasses()) {
return false; // rule 1
}
if (newContext.numAttributes() < originalContext.numAttributes()) {
return false; // rule 2
}
int oPos = 0;
int nPos = 0;
while (oPos < originalContext.numAttributes()) {
if (oPos == originalContext.classIndex()) {
oPos++;
if (!(oPos < originalContext.numAttributes())) {
break;
}
}
if (nPos == newContext.classIndex()) {
nPos++;
}
if (originalContext.attribute(oPos).isNominal()) {
if (!newContext.attribute(nPos).isNominal()) {
return false; // rule 4
}
if (newContext.attribute(nPos).numValues() < originalContext.attribute(oPos).numValues()) {
return false; // rule 3
}
} else {
assert (originalContext.attribute(oPos).isNumeric());
if (!newContext.attribute(nPos).isNumeric()) {
return false; // rule 4
}
}
oPos++;
nPos++;
}
return true; // all checks clear
}
public String getNominalValueString(int attIndex, int valIndex) {
return InstancesHeader.getNominalValueString(this.modelContext, attIndex, valIndex);
}
public String getAttributeNameString(int attIndex) {
return InstancesHeader.getAttributeNameString(this.modelContext, attIndex);
}
public String getClassLabelString(int classLabelIndex) {
return InstancesHeader.getClassLabelString(this.modelContext, classLabelIndex);
}
public String getClassNameString() {
return InstancesHeader.getClassNameString(this.modelContext);
}
