public void acceptInstance(InstanceEvent e) {
if (e.getStatus() == InstanceEvent.FORMAT_AVAILABLE) {
Instances structure = e.getStructure();
m_legendText = new Vector();
m_max = 1.0;
m_min = 0;
int i = 0;
for (i = 0; i < structure.numAttributes(); i++) {
if (i > 10) {
i--;
break;
}
m_legendText.addElement(structure.attribute(i).name());
m_legendPanel.repaint();
m_scalePanel.repaint();
}
m_dataPoint = new double[i];
m_xCount = 0;
return;
}
// process data point
Instance inst = e.getInstance();
for (int i = 0; i < m_dataPoint.length; i++) {
if (!inst.isMissing(i)) {
m_dataPoint[i] = inst.value(i);
}
}
acceptDataPoint(m_dataPoint);
m_xCount++;
}
/**
* Builds the ensemble of perceptrons.
*
* @exception Exception if something goes wrong during building
*/
public void buildClassifier(Instances insts) throws Exception {
if (insts.checkForStringAttributes()) {
throw new UnsupportedAttributeTypeException("Cannot handle string attributes!");
}
if (insts.numClasses() > 2) {
throw new Exception("Can only handle two-class datasets!");
}
if (insts.classAttribute().isNumeric()) {
throw new UnsupportedClassTypeException("Can't handle a numeric class!");
}
// Filter data
m_Train = new Instances(insts);
m_Train.deleteWithMissingClass();
m_ReplaceMissingValues = new ReplaceMissingValues();
m_ReplaceMissingValues.setInputFormat(m_Train);
m_Train = Filter.useFilter(m_Train, m_ReplaceMissingValues);
m_NominalToBinary = new NominalToBinary();
m_NominalToBinary.setInputFormat(m_Train);
m_Train = Filter.useFilter(m_Train, m_NominalToBinary);
/** Randomize training data */
m_Train.randomize(new Random(m_Seed));
/** Make space to store perceptrons */
m_Additions = new int[m_MaxK + 1];
m_IsAddition = new boolean[m_MaxK + 1];
m_Weights = new int[m_MaxK + 1];
/** Compute perceptrons */
m_K = 0;
out:
for (int it = 0; it < m_NumIterations; it++) {
for (int i = 0; i < m_Train.numInstances(); i++) {
Instance inst = m_Train.instance(i);
if (!inst.classIsMissing()) {
int prediction = makePrediction(m_K, inst);
int classValue = (int) inst.classValue();
if (prediction == classValue) {
m_Weights[m_K]++;
} else {
m_IsAddition[m_K] = (classValue == 1);
m_Additions[m_K] = i;
m_K++;
m_Weights[m_K]++;
}
if (m_K == m_MaxK) {
break out;
}
}
}
}
}
/**
* Builds a string listing the attribute values in a specified range of indices, separated by
* commas and enclosed in brackets.
*
* @param instance the instance to print the values from
* @param attributes the range of the attributes to list
* @return a string listing values of the attributes in the range
*/
private static String attributeValuesString(Instance instance, Range attRange) {
StringBuffer text = new StringBuffer();
if (attRange != null) {
boolean firstOutput = true;
attRange.setUpper(instance.numAttributes() - 1);
for (int i = 0; i < instance.numAttributes(); i++)
if (attRange.isInRange(i)) {
if (firstOutput) text.append("(");
else text.append(",");
text.append(instance.toString(i));
firstOutput = false;
}
if (!firstOutput) text.append(")");
}
return text.toString();
}
/** Computes the inner product of two instances */
private double innerProduct(Instance i1, Instance i2) throws Exception {
// we can do a fast dot product
double result = 0;
int n1 = i1.numValues();
int n2 = i2.numValues();
int classIndex = m_Train.classIndex();
for (int p1 = 0, p2 = 0; p1 < n1 && p2 < n2; ) {
int ind1 = i1.index(p1);
int ind2 = i2.index(p2);
if (ind1 == ind2) {
if (ind1 != classIndex) {
result += i1.valueSparse(p1) * i2.valueSparse(p2);
}
p1++;
p2++;
} else if (ind1 > ind2) {
p2++;
} else {
p1++;
}
}
result += 1.0;
if (m_Exponent != 1) {
return Math.pow(result, m_Exponent);
} else {
return result;
}
}
/**
* Calculates the class membership probabilities for the given test instance.
*
* @param instance the instance to be classified
* @return preedicted class probability distribution
* @exception Exception if distribution can't be computed successfully
*/
@Override
public double[] distributionForInstance(Instance instance) throws Exception {
double[] sums = new double[instance.numClasses()], newProbs;
for (int i = 0; i < m_NumIterations; i++) {
if (instance.classAttribute().isNumeric() == true) {
sums[0] += m_Classifiers[i].classifyInstance(instance);
} else {
newProbs = m_Classifiers[i].distributionForInstance(instance);
for (int j = 0; j < newProbs.length; j++) sums[j] += newProbs[j];
}
}
if (instance.classAttribute().isNumeric() == true) {
sums[0] /= m_NumIterations;
return sums;
} else if (Utils.eq(Utils.sum(sums), 0)) {
return sums;
} else {
Utils.normalize(sums);
return sums;
}
}
/**
* Bagging method.
*
* @param data the training data to be used for generating the bagged classifier.
* @exception Exception if the classifier could not be built successfully
*/
@Override
public void buildClassifier(Instances data) throws Exception {
super.buildClassifier(data);
if (m_CalcOutOfBag && (m_BagSizePercent != 100)) {
throw new IllegalArgumentException(
"Bag size needs to be 100% if " + "out-of-bag error is to be calculated!");
}
double outOfBagCount = 0.0;
double errorSum = 0.0;
int bagSize = data.numInstances() * m_BagSizePercent / 100;
Random random = new Random(m_Seed);
for (int j = 0; j < m_Classifiers.length; j++) {
Instances bagData = null;
boolean[] inBag = null;
// create the in-bag dataset
if (m_CalcOutOfBag) {
inBag = new boolean[data.numInstances()];
bagData = resampleWithWeights(data, random, inBag);
} else {
bagData = data.resampleWithWeights(random);
if (bagSize < data.numInstances()) {
bagData.randomize(random);
Instances newBagData = new Instances(bagData, 0, bagSize);
bagData = newBagData;
}
}
if (m_Classifier instanceof Randomizable) {
((Randomizable) m_Classifiers[j]).setSeed(random.nextInt());
}
// build the classifier
m_Classifiers[j].buildClassifier(bagData);
if (m_CalcOutOfBag) {
// calculate out of bag error
for (int i = 0; i < inBag.length; i++) {
if (!inBag[i]) {
Instance outOfBagInst = data.instance(i);
outOfBagCount += outOfBagInst.weight();
if (data.classAttribute().isNumeric()) {
errorSum +=
outOfBagInst.weight()
* Math.abs(
m_Classifiers[j].classifyInstance(outOfBagInst)
- outOfBagInst.classValue());
} else {
if (m_Classifiers[j].classifyInstance(outOfBagInst) != outOfBagInst.classValue()) {
errorSum += outOfBagInst.weight();
}
}
}
}
}
}
m_OutOfBagError = errorSum / outOfBagCount;
}
