@Override
public String classify(User user, Sample sample) {
Instances trainingSet =
new TrainingSetBuilder()
.setAttributes(user.getBssids())
.setClassAttribute(
"Location",
user.getLocations().stream().map(Location::getName).collect(Collectors.toList()))
.build("TrainingSet", 1);
// Create instance
Map<String, Integer> BSSIDLevelMap = getBSSIDLevelMap(sample);
Instance instance = new Instance(trainingSet.numAttributes());
for (Enumeration e = trainingSet.enumerateAttributes(); e.hasMoreElements(); ) {
Attribute attribute = (Attribute) e.nextElement();
String bssid = attribute.name();
int level = (BSSIDLevelMap.containsKey(bssid)) ? BSSIDLevelMap.get(bssid) : 0;
instance.setValue(attribute, level);
}
if (sample.getLocation() != null)
instance.setValue(trainingSet.classAttribute(), sample.getLocation());
instance.setDataset(trainingSet);
trainingSet.add(instance);
int predictedClass = classify(fromBase64(user.getClassifiers()), instance);
return trainingSet.classAttribute().value(predictedClass);
}
@Override
public List<Classifier> buildClassifiers(User user, List<Sample> validSamples) {
Instances trainingSet =
new TrainingSetBuilder()
.setAttributes(user.getBssids())
.setClassAttribute(
"Location",
user.getLocations().stream().map(Location::getName).collect(Collectors.toList()))
.build("TrainingSet", validSamples.size());
// Create instances
validSamples.forEach(
sample -> {
Map<String, Integer> BSSIDLevelMap = getBSSIDLevelMap(sample);
Instance instance = new Instance(trainingSet.numAttributes());
for (Enumeration e = trainingSet.enumerateAttributes(); e.hasMoreElements(); ) {
Attribute attribute = (Attribute) e.nextElement();
String bssid = attribute.name();
int level = (BSSIDLevelMap.containsKey(bssid)) ? BSSIDLevelMap.get(bssid) : 0;
instance.setValue(attribute, level);
}
instance.setValue(trainingSet.classAttribute(), sample.getLocation());
instance.setDataset(trainingSet);
trainingSet.add(instance);
});
// Build classifiers
List<Classifier> classifiers = buildClassifiers(trainingSet);
return classifiers;
}
/**
* Compute the number of all possible conditions that could appear in a rule of a given data. For
* nominal attributes, it's the number of values that could appear; for numeric attributes, it's
* the number of values * 2, i.e. <= and >= are counted as different possible conditions.
*
* @param data the given data
* @return number of all conditions of the data
*/
public static double numAllConditions(Instances data) {
double total = 0;
Enumeration attEnum = data.enumerateAttributes();
while (attEnum.hasMoreElements()) {
Attribute att = (Attribute) attEnum.nextElement();
if (att.isNominal()) total += (double) att.numValues();
else total += 2.0 * (double) data.numDistinctValues(att);
}
return total;
}
/**
* Zwraca list?? dost??pnych atrybut??w.
*
* @return Lista dost??pnych atrybut??w.
*/
public List<String> getAttributeNames() {
Enumeration e = data.enumerateAttributes();
List<String> attributeNames = new ArrayList<String>();
while (e.hasMoreElements()) {
attributeNames.add(((Attribute) e.nextElement()).name());
}
return attributeNames;
}
/**
* Returns a description of the classifier.
*
* @return a description of the classifier as a string.
*/
@Override
public String toString() {
if (m_Instances == null) {
return "Naive Bayes (simple): No model built yet.";
}
try {
StringBuffer text = new StringBuffer("Naive Bayes (simple)");
int attIndex;
for (int i = 0; i < m_Instances.numClasses(); i++) {
text.append(
"\n\nClass "
+ m_Instances.classAttribute().value(i)
+ ": P(C) = "
+ Utils.doubleToString(m_Priors[i], 10, 8)
+ "\n\n");
Enumeration<Attribute> enumAtts = m_Instances.enumerateAttributes();
attIndex = 0;
while (enumAtts.hasMoreElements()) {
Attribute attribute = enumAtts.nextElement();
text.append("Attribute " + attribute.name() + "\n");
if (attribute.isNominal()) {
for (int j = 0; j < attribute.numValues(); j++) {
text.append(attribute.value(j) + "\t");
}
text.append("\n");
for (int j = 0; j < attribute.numValues(); j++) {
text.append(Utils.doubleToString(m_Counts[i][attIndex][j], 10, 8) + "\t");
}
} else {
text.append("Mean: " + Utils.doubleToString(m_Means[i][attIndex], 10, 8) + "\t");
text.append("Standard Deviation: " + Utils.doubleToString(m_Devs[i][attIndex], 10, 8));
}
text.append("\n\n");
attIndex++;
}
}
return text.toString();
} catch (Exception e) {
return "Can't print Naive Bayes classifier!";
}
}
/**
* Method for building an Id3 tree.
*
* @param data the training data
* @exception Exception if decision tree can't be built successfully
*/
private void makeTree(Instances data) throws Exception {
// Check if no instances have reached this node.
if (data.numInstances() == 0) {
m_Attribute = null;
m_ClassValue = Utils.missingValue();
m_Distribution = new double[data.numClasses()];
return;
}
// Compute attribute with maximum information gain.
double[] infoGains = new double[data.numAttributes()];
Enumeration attEnum = data.enumerateAttributes();
while (attEnum.hasMoreElements()) {
Attribute att = (Attribute) attEnum.nextElement();
infoGains[att.index()] = computeInfoGain(data, att);
}
m_Attribute = data.attribute(Utils.maxIndex(infoGains));
// Make leaf if information gain is zero.
// Otherwise create successors.
if (Utils.eq(infoGains[m_Attribute.index()], 0)) {
m_Attribute = null;
m_Distribution = new double[data.numClasses()];
Enumeration instEnum = data.enumerateInstances();
while (instEnum.hasMoreElements()) {
Instance inst = (Instance) instEnum.nextElement();
m_Distribution[(int) inst.classValue()]++;
}
Utils.normalize(m_Distribution);
m_ClassValue = Utils.maxIndex(m_Distribution);
m_ClassAttribute = data.classAttribute();
} else {
Instances[] splitData = splitData(data, m_Attribute);
m_Successors = new Id3[m_Attribute.numValues()];
for (int j = 0; j < m_Attribute.numValues(); j++) {
m_Successors[j] = new Id3();
m_Successors[j].makeTree(splitData[j]);
}
}
}
/**
* Generates the classifier.
*
* @param instances set of instances serving as training data
* @exception Exception if the classifier has not been generated successfully
*/
@Override
public void buildClassifier(Instances instances) throws Exception {
int attIndex = 0;
double sum;
// can classifier handle the data?
getCapabilities().testWithFail(instances);
// remove instances with missing class
instances = new Instances(instances);
instances.deleteWithMissingClass();
m_Instances = new Instances(instances, 0);
// Reserve space
m_Counts = new double[instances.numClasses()][instances.numAttributes() - 1][0];
m_Means = new double[instances.numClasses()][instances.numAttributes() - 1];
m_Devs = new double[instances.numClasses()][instances.numAttributes() - 1];
m_Priors = new double[instances.numClasses()];
Enumeration<Attribute> enu = instances.enumerateAttributes();
while (enu.hasMoreElements()) {
Attribute attribute = enu.nextElement();
if (attribute.isNominal()) {
for (int j = 0; j < instances.numClasses(); j++) {
m_Counts[j][attIndex] = new double[attribute.numValues()];
}
} else {
for (int j = 0; j < instances.numClasses(); j++) {
m_Counts[j][attIndex] = new double[1];
}
}
attIndex++;
}
// Compute counts and sums
Enumeration<Instance> enumInsts = instances.enumerateInstances();
while (enumInsts.hasMoreElements()) {
Instance instance = enumInsts.nextElement();
if (!instance.classIsMissing()) {
Enumeration<Attribute> enumAtts = instances.enumerateAttributes();
attIndex = 0;
while (enumAtts.hasMoreElements()) {
Attribute attribute = enumAtts.nextElement();
if (!instance.isMissing(attribute)) {
if (attribute.isNominal()) {
m_Counts[(int) instance.classValue()][attIndex][(int) instance.value(attribute)]++;
} else {
m_Means[(int) instance.classValue()][attIndex] += instance.value(attribute);
m_Counts[(int) instance.classValue()][attIndex][0]++;
}
}
attIndex++;
}
m_Priors[(int) instance.classValue()]++;
}
}
// Compute means
Enumeration<Attribute> enumAtts = instances.enumerateAttributes();
attIndex = 0;
while (enumAtts.hasMoreElements()) {
Attribute attribute = enumAtts.nextElement();
if (attribute.isNumeric()) {
for (int j = 0; j < instances.numClasses(); j++) {
if (m_Counts[j][attIndex][0] < 2) {
throw new Exception(
"attribute "
+ attribute.name()
+ ": less than two values for class "
+ instances.classAttribute().value(j));
}
m_Means[j][attIndex] /= m_Counts[j][attIndex][0];
}
}
attIndex++;
}
// Compute standard deviations
enumInsts = instances.enumerateInstances();
while (enumInsts.hasMoreElements()) {
Instance instance = enumInsts.nextElement();
if (!instance.classIsMissing()) {
enumAtts = instances.enumerateAttributes();
attIndex = 0;
while (enumAtts.hasMoreElements()) {
Attribute attribute = enumAtts.nextElement();
if (!instance.isMissing(attribute)) {
if (attribute.isNumeric()) {
m_Devs[(int) instance.classValue()][attIndex] +=
(m_Means[(int) instance.classValue()][attIndex] - instance.value(attribute))
* (m_Means[(int) instance.classValue()][attIndex]
- instance.value(attribute));
}
}
attIndex++;
}
}
}
enumAtts = instances.enumerateAttributes();
attIndex = 0;
while (enumAtts.hasMoreElements()) {
Attribute attribute = enumAtts.nextElement();
if (attribute.isNumeric()) {
for (int j = 0; j < instances.numClasses(); j++) {
if (m_Devs[j][attIndex] <= 0) {
throw new Exception(
"attribute "
+ attribute.name()
+ ": standard deviation is 0 for class "
+ instances.classAttribute().value(j));
} else {
m_Devs[j][attIndex] /= m_Counts[j][attIndex][0] - 1;
m_Devs[j][attIndex] = Math.sqrt(m_Devs[j][attIndex]);
}
}
}
attIndex++;
}
// Normalize counts
enumAtts = instances.enumerateAttributes();
attIndex = 0;
while (enumAtts.hasMoreElements()) {
Attribute attribute = enumAtts.nextElement();
if (attribute.isNominal()) {
for (int j = 0; j < instances.numClasses(); j++) {
sum = Utils.sum(m_Counts[j][attIndex]);
for (int i = 0; i < attribute.numValues(); i++) {
m_Counts[j][attIndex][i] =
(m_Counts[j][attIndex][i] + 1) / (sum + attribute.numValues());
}
}
}
attIndex++;
}
// Normalize priors
sum = Utils.sum(m_Priors);
for (int j = 0; j < instances.numClasses(); j++) {
m_Priors[j] = (m_Priors[j] + 1) / (sum + instances.numClasses());
}
}
