/* (non-Javadoc)
* @see org.apache.hadoop.mapreduce.Reducer#reduce(KEYIN, java.lang.Iterable, org.apache.hadoop.mapreduce.Reducer.Context)
*/
protected void reduce(Tuple key, Iterable<Tuple> values, Context context)
throws IOException, InterruptedException {
if (stBld.length() > 0) {
stBld.delete(0, stBld.length());
}
testEntityId = key.getString(0);
stBld.append(testEntityId);
// collect nearest neighbors
count = 0;
neighborhood.initialize();
for (Tuple value : values) {
int index = 0;
trainEntityId = value.getString(index++);
distance = value.getInt(index++);
trainClassValue = value.getString(index++);
if (classCondtionWeighted && neighborhood.IsInClassificationMode()) {
trainingFeaturePostProb = value.getDouble(index++);
if (inverseDistanceWeighted) {
neighborhood.addNeighbor(
trainEntityId, distance, trainClassValue, trainingFeaturePostProb, true);
} else {
neighborhood.addNeighbor(
trainEntityId, distance, trainClassValue, trainingFeaturePostProb);
}
} else {
Neighborhood.Neighbor neighbor =
neighborhood.addNeighbor(trainEntityId, distance, trainClassValue);
if (neighborhood.isInLinearRegressionMode()) {
neighbor.setRegrInputVar(Double.parseDouble(value.getString(index++)));
}
}
if (++count == topMatchCount) {
break;
}
}
if (neighborhood.isInLinearRegressionMode()) {
String testRegrNumFld = isValidationMode ? key.getString(2) : key.getString(1);
neighborhood.withRegrInputVar(Double.parseDouble(testRegrNumFld));
}
// class distribution
neighborhood.processClassDitribution();
if (outputClassDistr && neighborhood.IsInClassificationMode()) {
if (classCondtionWeighted) {
Map<String, Double> classDistr = neighborhood.getWeightedClassDitribution();
double thisScore;
for (String classVal : classDistr.keySet()) {
thisScore = classDistr.get(classVal);
// LOG.debug("classVal:" + classVal + " thisScore:" + thisScore);
stBld.append(fieldDelim).append(classVal).append(fieldDelim).append(thisScore);
}
} else {
Map<String, Integer> classDistr = neighborhood.getClassDitribution();
int thisScore;
for (String classVal : classDistr.keySet()) {
thisScore = classDistr.get(classVal);
stBld.append(classVal).append(fieldDelim).append(thisScore);
}
}
}
if (isValidationMode) {
// actual class attr value
testClassValActual = key.getString(1);
stBld.append(fieldDelim).append(testClassValActual);
}
// predicted class value
if (useCostBasedClassifier) {
// use cost based arbitrator
if (neighborhood.IsInClassificationMode()) {
posClassProbab = neighborhood.getClassProb(posClassAttrValue);
testClassValPredicted = costBasedArbitrator.classify(posClassProbab);
}
} else {
// get directly
if (neighborhood.IsInClassificationMode()) {
testClassValPredicted = neighborhood.classify();
} else {
testClassValPredicted = "" + neighborhood.getPredictedValue();
}
}
stBld.append(fieldDelim).append(testClassValPredicted);
if (isValidationMode) {
if (neighborhood.IsInClassificationMode()) {
confMatrix.report(testClassValPredicted, testClassValActual);
}
}
outVal.set(stBld.toString());
context.write(NullWritable.get(), outVal);
}
