/**
* Inserts an instance into the hash table
*
* @param inst instance to be inserted
* @param instA to create the hash key from
* @throws Exception if the instance can't be inserted
*/
private void insertIntoTable(Instance inst, double[] instA) throws Exception {
double[] tempClassDist2;
double[] newDist;
DecisionTableHashKey thekey;
if (instA != null) {
thekey = new DecisionTableHashKey(instA);
} else {
thekey = new DecisionTableHashKey(inst, inst.numAttributes(), false);
}
// see if this one is already in the table
tempClassDist2 = (double[]) m_entries.get(thekey);
if (tempClassDist2 == null) {
if (m_classIsNominal) {
newDist = new double[m_theInstances.classAttribute().numValues()];
// Leplace estimation
for (int i = 0; i < m_theInstances.classAttribute().numValues(); i++) {
newDist[i] = 1.0;
}
newDist[(int) inst.classValue()] = inst.weight();
// add to the table
m_entries.put(thekey, newDist);
} else {
newDist = new double[2];
newDist[0] = inst.classValue() * inst.weight();
newDist[1] = inst.weight();
// add to the table
m_entries.put(thekey, newDist);
}
} else {
// update the distribution for this instance
if (m_classIsNominal) {
tempClassDist2[(int) inst.classValue()] += inst.weight();
// update the table
m_entries.put(thekey, tempClassDist2);
} else {
tempClassDist2[0] += (inst.classValue() * inst.weight());
tempClassDist2[1] += inst.weight();
// update the table
m_entries.put(thekey, tempClassDist2);
}
}
}
/**
* Updates the minimum and maximum values for all the attributes based on a new instance.
*
* @param instance the new instance
*/
private void updateMinMax(Instance instance) {
for (int j = 0; j < instance.numAttributes(); j++) {
if (Double.isNaN(m_Min[j])) {
m_Min[j] = instance.value(j);
m_Max[j] = instance.value(j);
} else {
if (instance.value(j) < m_Min[j]) {
m_Min[j] = instance.value(j);
} else {
if (instance.value(j) > m_Max[j]) {
m_Max[j] = instance.value(j);
}
}
}
}
}
/**
* Calculates the class membership probabilities for the given test instance.
*
* @param instance the instance to be classified
* @return predicted class probability distribution
* @throws Exception if distribution can't be computed
*/
public double[] distributionForInstance(Instance instance) throws Exception {
DecisionTableHashKey thekey;
double[] tempDist;
double[] normDist;
m_disTransform.input(instance);
m_disTransform.batchFinished();
instance = m_disTransform.output();
m_delTransform.input(instance);
m_delTransform.batchFinished();
instance = m_delTransform.output();
thekey = new DecisionTableHashKey(instance, instance.numAttributes(), false);
// if this one is not in the table
if ((tempDist = (double[]) m_entries.get(thekey)) == null) {
if (m_useIBk) {
tempDist = m_ibk.distributionForInstance(instance);
} else {
if (!m_classIsNominal) {
tempDist = new double[1];
tempDist[0] = m_majority;
} else {
tempDist = m_classPriors.clone();
/*tempDist = new double [m_theInstances.classAttribute().numValues()];
tempDist[(int)m_majority] = 1.0; */
}
}
} else {
if (!m_classIsNominal) {
normDist = new double[1];
normDist[0] = (tempDist[0] / tempDist[1]);
tempDist = normDist;
} else {
// normalise distribution
normDist = new double[tempDist.length];
System.arraycopy(tempDist, 0, normDist, 0, tempDist.length);
Utils.normalize(normDist);
tempDist = normDist;
}
}
return tempDist;
}
