/**
* Normalize the weights for the next iteration.
*
* @param training the training instances
* @throws Exception if something goes wrong
*/
protected void normalizeWeights(Instances training, double oldSumOfWeights) throws Exception {
// Renormalize weights
double newSumOfWeights = training.sumOfWeights();
for (Instance instance : training) {
instance.setWeight(instance.weight() * oldSumOfWeights / newSumOfWeights);
}
}
@Override
public void trainOnInstanceImpl(Instance inst) {
double lambda_d = 1.0;
for (int i = 0; i < this.ensemble.length; i++) {
double k =
this.pureBoostOption.isSet()
? lambda_d
: MiscUtils.poisson(lambda_d, this.classifierRandom);
if (k > 0.0) {
Instance weightedInst = (Instance) inst.copy();
weightedInst.setWeight(inst.weight() * k);
this.ensemble[i].trainOnInstance(weightedInst);
}
if (this.ensemble[i].correctlyClassifies(inst)) {
this.scms[i] += lambda_d;
lambda_d *= this.trainingWeightSeenByModel / (2 * this.scms[i]);
} else {
this.swms[i] += lambda_d;
lambda_d *= this.trainingWeightSeenByModel / (2 * this.swms[i]);
}
}
}
/**
* Sets the weights for the next iteration.
*
* @param training the training instances
* @throws Exception if something goes wrong
*/
protected void setWeights(Instances training, int iteration) throws Exception {
for (Instance instance : training) {
double reweight = 1;
double prob = 1, shrinkage = m_Shrinkage;
if (iteration == -1) {
prob = m_ZeroR.distributionForInstance(instance)[0];
shrinkage = 1.0;
} else {
prob = m_Classifiers[iteration].distributionForInstance(instance)[0];
// Make sure that probabilities are never 0 or 1 using ad-hoc smoothing
prob = (m_SumOfWeights * prob + 1) / (m_SumOfWeights + 2);
}
if (instance.classValue() == 1) {
reweight = shrinkage * 0.5 * (Math.log(prob) - Math.log(1 - prob));
} else {
reweight = shrinkage * 0.5 * (Math.log(1 - prob) - Math.log(prob));
}
instance.setWeight(instance.weight() * Math.exp(reweight));
}
}
/**
* Accepts and processes a classifier encapsulated in an incremental classifier event
*
* @param ce an <code>IncrementalClassifierEvent</code> value
*/
@Override
public void acceptClassifier(final IncrementalClassifierEvent ce) {
try {
if (ce.getStatus() == IncrementalClassifierEvent.NEW_BATCH) {
m_throughput = new StreamThroughput(statusMessagePrefix());
m_throughput.setSamplePeriod(m_statusFrequency);
// m_eval = new Evaluation(ce.getCurrentInstance().dataset());
m_eval = new Evaluation(ce.getStructure());
m_eval.useNoPriors();
m_dataLegend = new Vector();
m_reset = true;
m_dataPoint = new double[0];
Instances inst = ce.getStructure();
System.err.println("NEW BATCH");
m_instanceCount = 0;
if (m_windowSize > 0) {
m_window = new LinkedList<Instance>();
m_windowEval = new Evaluation(ce.getStructure());
m_windowEval.useNoPriors();
m_windowedPreds = new LinkedList<double[]>();
if (m_logger != null) {
m_logger.logMessage(
statusMessagePrefix()
+ "[IncrementalClassifierEvaluator] Chart output using windowed "
+ "evaluation over "
+ m_windowSize
+ " instances");
}
}
/*
* if (m_logger != null) { m_logger.statusMessage(statusMessagePrefix()
* + "IncrementalClassifierEvaluator: started processing...");
* m_logger.logMessage(statusMessagePrefix() +
* " [IncrementalClassifierEvaluator]" + statusMessagePrefix() +
* " started processing..."); }
*/
} else {
Instance inst = ce.getCurrentInstance();
if (inst != null) {
m_throughput.updateStart();
m_instanceCount++;
// if (inst.attribute(inst.classIndex()).isNominal()) {
double[] dist = ce.getClassifier().distributionForInstance(inst);
double pred = 0;
if (!inst.isMissing(inst.classIndex())) {
if (m_outputInfoRetrievalStats) {
// store predictions so AUC etc can be output.
m_eval.evaluateModelOnceAndRecordPrediction(dist, inst);
} else {
m_eval.evaluateModelOnce(dist, inst);
}
if (m_windowSize > 0) {
m_windowEval.evaluateModelOnce(dist, inst);
m_window.addFirst(inst);
m_windowedPreds.addFirst(dist);
if (m_instanceCount > m_windowSize) {
// "forget" the oldest prediction
Instance oldest = m_window.removeLast();
double[] oldDist = m_windowedPreds.removeLast();
oldest.setWeight(-oldest.weight());
m_windowEval.evaluateModelOnce(oldDist, oldest);
oldest.setWeight(-oldest.weight());
}
}
} else {
pred = ce.getClassifier().classifyInstance(inst);
}
if (inst.classIndex() >= 0) {
// need to check that the class is not missing
if (inst.attribute(inst.classIndex()).isNominal()) {
if (!inst.isMissing(inst.classIndex())) {
if (m_dataPoint.length < 2) {
m_dataPoint = new double[3];
m_dataLegend.addElement("Accuracy");
m_dataLegend.addElement("RMSE (prob)");
m_dataLegend.addElement("Kappa");
}
// int classV = (int) inst.value(inst.classIndex());
if (m_windowSize > 0) {
m_dataPoint[1] = m_windowEval.rootMeanSquaredError();
m_dataPoint[2] = m_windowEval.kappa();
} else {
m_dataPoint[1] = m_eval.rootMeanSquaredError();
m_dataPoint[2] = m_eval.kappa();
}
// int maxO = Utils.maxIndex(dist);
// if (maxO == classV) {
// dist[classV] = -1;
// maxO = Utils.maxIndex(dist);
// }
// m_dataPoint[1] -= dist[maxO];
} else {
if (m_dataPoint.length < 1) {
m_dataPoint = new double[1];
m_dataLegend.addElement("Confidence");
}
}
double primaryMeasure = 0;
if (!inst.isMissing(inst.classIndex())) {
if (m_windowSize > 0) {
primaryMeasure = 1.0 - m_windowEval.errorRate();
} else {
primaryMeasure = 1.0 - m_eval.errorRate();
}
} else {
// record confidence as the primary measure
// (another possibility would be entropy of
// the distribution, or perhaps average
// confidence)
primaryMeasure = dist[Utils.maxIndex(dist)];
}
// double [] dataPoint = new double[1];
m_dataPoint[0] = primaryMeasure;
// double min = 0; double max = 100;
/*
* ChartEvent e = new
* ChartEvent(IncrementalClassifierEvaluator.this, m_dataLegend,
* min, max, dataPoint);
*/
m_ce.setLegendText(m_dataLegend);
m_ce.setMin(0);
m_ce.setMax(1);
m_ce.setDataPoint(m_dataPoint);
m_ce.setReset(m_reset);
m_reset = false;
} else {
// numeric class
if (m_dataPoint.length < 1) {
m_dataPoint = new double[1];
if (inst.isMissing(inst.classIndex())) {
m_dataLegend.addElement("Prediction");
} else {
m_dataLegend.addElement("RMSE");
}
}
if (!inst.isMissing(inst.classIndex())) {
double update;
if (!inst.isMissing(inst.classIndex())) {
if (m_windowSize > 0) {
update = m_windowEval.rootMeanSquaredError();
} else {
update = m_eval.rootMeanSquaredError();
}
} else {
update = pred;
}
m_dataPoint[0] = update;
if (update > m_max) {
m_max = update;
}
if (update < m_min) {
m_min = update;
}
}
m_ce.setLegendText(m_dataLegend);
m_ce.setMin((inst.isMissing(inst.classIndex()) ? m_min : 0));
m_ce.setMax(m_max);
m_ce.setDataPoint(m_dataPoint);
m_ce.setReset(m_reset);
m_reset = false;
}
notifyChartListeners(m_ce);
}
m_throughput.updateEnd(m_logger);
}
if (ce.getStatus() == IncrementalClassifierEvent.BATCH_FINISHED || inst == null) {
if (m_logger != null) {
m_logger.logMessage(
"[IncrementalClassifierEvaluator]"
+ statusMessagePrefix()
+ " Finished processing.");
}
m_throughput.finished(m_logger);
// save memory if using windowed evaluation for charting
m_windowEval = null;
m_window = null;
m_windowedPreds = null;
if (m_textListeners.size() > 0) {
String textTitle = ce.getClassifier().getClass().getName();
textTitle = textTitle.substring(textTitle.lastIndexOf('.') + 1, textTitle.length());
String results =
"=== Performance information ===\n\n"
+ "Scheme: "
+ textTitle
+ "\n"
+ "Relation: "
+ m_eval.getHeader().relationName()
+ "\n\n"
+ m_eval.toSummaryString();
if (m_eval.getHeader().classIndex() >= 0
&& m_eval.getHeader().classAttribute().isNominal()
&& (m_outputInfoRetrievalStats)) {
results += "\n" + m_eval.toClassDetailsString();
}
if (m_eval.getHeader().classIndex() >= 0
&& m_eval.getHeader().classAttribute().isNominal()) {
results += "\n" + m_eval.toMatrixString();
}
textTitle = "Results: " + textTitle;
TextEvent te = new TextEvent(this, results, textTitle);
notifyTextListeners(te);
}
}
}
} catch (Exception ex) {
if (m_logger != null) {
m_logger.logMessage(
"[IncrementalClassifierEvaluator]"
+ statusMessagePrefix()
+ " Error processing prediction "
+ ex.getMessage());
m_logger.statusMessage(
statusMessagePrefix() + "ERROR: problem processing prediction (see log for details)");
}
ex.printStackTrace();
stop();
}
}
/**
* Calculates the class membership probabilities for the given test instance.
*
* @param instance the instance to be classified
* @return preedicted class probability distribution
* @throws Exception if distribution can't be computed successfully
*/
public double[] distributionForInstance(Instance instance) throws Exception {
// default model?
if (m_ZeroR != null) {
return m_ZeroR.distributionForInstance(instance);
}
if (m_Train.numInstances() == 0) {
throw new Exception("No training instances!");
}
m_NNSearch.addInstanceInfo(instance);
int k = m_Train.numInstances();
if ((!m_UseAllK && (m_kNN < k)) /*&&
!(m_WeightKernel==INVERSE ||
m_WeightKernel==GAUSS)*/) {
k = m_kNN;
}
Instances neighbours = m_NNSearch.kNearestNeighbours(instance, k);
double distances[] = m_NNSearch.getDistances();
if (m_Debug) {
System.out.println("Test Instance: " + instance);
System.out.println(
"For "
+ k
+ " kept "
+ neighbours.numInstances()
+ " out of "
+ m_Train.numInstances()
+ " instances.");
}
// IF LinearNN has skipped so much that <k neighbours are remaining.
if (k > distances.length) k = distances.length;
if (m_Debug) {
System.out.println("Instance Distances");
for (int i = 0; i < distances.length; i++) {
System.out.println("" + distances[i]);
}
}
// Determine the bandwidth
double bandwidth = distances[k - 1];
// Check for bandwidth zero
if (bandwidth <= 0) {
// if the kth distance is zero than give all instances the same weight
for (int i = 0; i < distances.length; i++) distances[i] = 1;
} else {
// Rescale the distances by the bandwidth
for (int i = 0; i < distances.length; i++) distances[i] = distances[i] / bandwidth;
}
// Pass the distances through a weighting kernel
for (int i = 0; i < distances.length; i++) {
switch (m_WeightKernel) {
case LINEAR:
distances[i] = 1.0001 - distances[i];
break;
case EPANECHNIKOV:
distances[i] = 3 / 4D * (1.0001 - distances[i] * distances[i]);
break;
case TRICUBE:
distances[i] = Math.pow((1.0001 - Math.pow(distances[i], 3)), 3);
break;
case CONSTANT:
// System.err.println("using constant kernel");
distances[i] = 1;
break;
case INVERSE:
distances[i] = 1.0 / (1.0 + distances[i]);
break;
case GAUSS:
distances[i] = Math.exp(-distances[i] * distances[i]);
break;
}
}
if (m_Debug) {
System.out.println("Instance Weights");
for (int i = 0; i < distances.length; i++) {
System.out.println("" + distances[i]);
}
}
// Set the weights on the training data
double sumOfWeights = 0, newSumOfWeights = 0;
for (int i = 0; i < distances.length; i++) {
double weight = distances[i];
Instance inst = (Instance) neighbours.instance(i);
sumOfWeights += inst.weight();
newSumOfWeights += inst.weight() * weight;
inst.setWeight(inst.weight() * weight);
// weightedTrain.add(newInst);
}
// Rescale weights
for (int i = 0; i < neighbours.numInstances(); i++) {
Instance inst = neighbours.instance(i);
inst.setWeight(inst.weight() * sumOfWeights / newSumOfWeights);
}
// Create a weighted classifier
m_Classifier.buildClassifier(neighbours);
if (m_Debug) {
System.out.println("Classifying test instance: " + instance);
System.out.println("Built base classifier:\n" + m_Classifier.toString());
}
// Return the classifier's predictions
return m_Classifier.distributionForInstance(instance);
}
