/**
* Constructor that generates a sparse instance from the given instance. Reference to the dataset
* is set to null. (ie. the instance doesn't have access to information about the attribute types)
*
* @param instance the instance from which the attribute values and the weight are to be copied
*/
public SparseInstance(Instance instance) {
m_Weight = instance.weight();
m_Dataset = null;
m_NumAttributes = instance.numAttributes();
if (instance instanceof SparseInstance) {
m_AttValues = ((SparseInstance) instance).m_AttValues;
m_Indices = ((SparseInstance) instance).m_Indices;
} else {
double[] tempValues = new double[instance.numAttributes()];
int[] tempIndices = new int[instance.numAttributes()];
int vals = 0;
for (int i = 0; i < instance.numAttributes(); i++) {
if (instance.value(i) != 0) {
tempValues[vals] = instance.value(i);
tempIndices[vals] = i;
vals++;
}
}
m_AttValues = new double[vals];
m_Indices = new int[vals];
System.arraycopy(tempValues, 0, m_AttValues, 0, vals);
System.arraycopy(tempIndices, 0, m_Indices, 0, vals);
}
}
/**
* Whether the instance is covered by this antecedent
*
* @param inst the instance in question
* @return the boolean value indicating whether the instance is covered by this antecedent
*/
public double covers(Instance inst) {
double isCover = 0;
if (!inst.isMissing(att)) {
if ((int) inst.value(att) == (int) value) isCover = 1;
}
return isCover;
}
/**
* 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);
}
}
}
}
}
/**
* Updates the ranges given a new instance.
*
* @param instance the new instance
* @param ranges low, high and width values for all attributes
* @return the updated ranges
*/
public double[][] updateRanges(Instance instance, double[][] ranges) {
// updateRangesFirst must have been called on ranges
for (int j = 0; j < ranges.length; j++) {
double value = instance.value(j);
if (!instance.isMissing(j)) {
if (value < ranges[j][R_MIN]) {
ranges[j][R_MIN] = value;
ranges[j][R_WIDTH] = ranges[j][R_MAX] - ranges[j][R_MIN];
} else {
if (instance.value(j) > ranges[j][R_MAX]) {
ranges[j][R_MAX] = value;
ranges[j][R_WIDTH] = ranges[j][R_MAX] - ranges[j][R_MIN];
}
}
}
}
return ranges;
}
/**
* Determines the output format based on the input format and returns this. In case the output
* format cannot be returned immediately, i.e., immediateOutputFormat() returns false, then this
* method will be called from batchFinished().
*
* @param inputFormat the input format to base the output format on
* @return the output format
* @throws Exception in case the determination goes wrong
* @see #hasImmediateOutputFormat()
* @see #batchFinished()
*/
protected Instances determineOutputFormat(Instances inputFormat) throws Exception {
Instances data;
Instances result;
FastVector atts;
FastVector values;
HashSet hash;
int i;
int n;
boolean isDate;
Instance inst;
Vector sorted;
m_Cols.setUpper(inputFormat.numAttributes() - 1);
data = new Instances(inputFormat);
atts = new FastVector();
for (i = 0; i < data.numAttributes(); i++) {
if (!m_Cols.isInRange(i) || !data.attribute(i).isNumeric()) {
atts.addElement(data.attribute(i));
continue;
}
// date attribute?
isDate = (data.attribute(i).type() == Attribute.DATE);
// determine all available attribtues in dataset
hash = new HashSet();
for (n = 0; n < data.numInstances(); n++) {
inst = data.instance(n);
if (inst.isMissing(i)) continue;
if (isDate) hash.add(inst.stringValue(i));
else hash.add(new Double(inst.value(i)));
}
// sort values
sorted = new Vector();
for (Object o : hash) sorted.add(o);
Collections.sort(sorted);
// create attribute from sorted values
values = new FastVector();
for (Object o : sorted) {
if (isDate) values.addElement(o.toString());
else values.addElement(Utils.doubleToString(((Double) o).doubleValue(), MAX_DECIMALS));
}
atts.addElement(new Attribute(data.attribute(i).name(), values));
}
result = new Instances(inputFormat.relationName(), atts, 0);
result.setClassIndex(inputFormat.classIndex());
return result;
}
/**
* Classifies a given test instance using the decision tree.
*
* @param instance the instance to be classified
* @return the classification
* @throws NoSupportForMissingValuesException if instance has missing values
*/
public double classifyInstance(Instance instance) throws NoSupportForMissingValuesException {
if (instance.hasMissingValue()) {
throw new NoSupportForMissingValuesException("Id3: no missing values, " + "please.");
}
if (m_Attribute == null) {
return m_ClassValue;
} else {
return m_Successors[(int) instance.value(m_Attribute)].classifyInstance(instance);
}
}
public double classifyInstance(Instance inst) throws Exception {
if (m_attribute == null) {
return m_intercept;
} else {
if (inst.isMissing(m_attribute.index())) {
throw new Exception("UnivariateLinearRegression: No missing values!");
}
return m_intercept + m_slope * inst.value(m_attribute.index());
}
}
/**
* Used to initialize the ranges. For this the values of the first instance is used to save time.
* Sets low and high to the values of the first instance and width to zero.
*
* @param instance the new instance
* @param numAtt number of attributes in the model
* @param ranges low, high and width values for all attributes
*/
public void updateRangesFirst(Instance instance, int numAtt, double[][] ranges) {
for (int j = 0; j < numAtt; j++) {
if (!instance.isMissing(j)) {
ranges[j][R_MIN] = instance.value(j);
ranges[j][R_MAX] = instance.value(j);
ranges[j][R_WIDTH] = 0.0;
} else { // if value was missing
ranges[j][R_MIN] = Double.POSITIVE_INFINITY;
ranges[j][R_MAX] = -Double.POSITIVE_INFINITY;
ranges[j][R_WIDTH] = Double.POSITIVE_INFINITY;
}
}
}
/**
* Gets the subset of instances that apply to a particluar branch of the split. If the branch
* index is -1, the subset will consist of those instances that don't apply to any branch.
*
* @param branch the index of the branch
* @param sourceInstances the instances from which to find the subset
* @return the set of instances that apply
*/
public ReferenceInstances instancesDownBranch(int branch, Instances instances) {
ReferenceInstances filteredInstances = new ReferenceInstances(instances, 1);
if (branch == -1) {
for (Enumeration e = instances.enumerateInstances(); e.hasMoreElements(); ) {
Instance inst = (Instance) e.nextElement();
if (inst.isMissing(attIndex)) filteredInstances.addReference(inst);
}
} else if (branch == 0) {
for (Enumeration e = instances.enumerateInstances(); e.hasMoreElements(); ) {
Instance inst = (Instance) e.nextElement();
if (!inst.isMissing(attIndex) && inst.value(attIndex) < splitPoint)
filteredInstances.addReference(inst);
}
} else {
for (Enumeration e = instances.enumerateInstances(); e.hasMoreElements(); ) {
Instance inst = (Instance) e.nextElement();
if (!inst.isMissing(attIndex) && inst.value(attIndex) >= splitPoint)
filteredInstances.addReference(inst);
}
}
return filteredInstances;
}
/**
* Test if an instance is within the given ranges.
*
* @param instance the instance
* @param ranges the ranges the instance is tested to be in
* @return true if instance is within the ranges
*/
public boolean inRanges(Instance instance, double[][] ranges) {
boolean isIn = true;
// updateRangesFirst must have been called on ranges
for (int j = 0; isIn && (j < ranges.length); j++) {
if (!instance.isMissing(j)) {
double value = instance.value(j);
isIn = value <= ranges[j][R_MAX];
if (isIn) {
isIn = value >= ranges[j][R_MIN];
}
}
}
return isIn;
}
/**
* Splits a dataset according to the values of a nominal attribute.
*
* @param data the data which is to be split
* @param att the attribute to be used for splitting
* @return the sets of instances produced by the split
*/
private Instances[] splitData(Instances data, Attribute att) {
Instances[] splitData = new Instances[att.numValues()];
for (int j = 0; j < att.numValues(); j++) {
splitData[j] = new Instances(data, data.numInstances());
}
Enumeration instEnum = data.enumerateInstances();
while (instEnum.hasMoreElements()) {
Instance inst = (Instance) instEnum.nextElement();
splitData[(int) inst.value(att)].add(inst);
}
for (int i = 0; i < splitData.length; i++) {
splitData[i].compactify();
}
return splitData;
}
/**
* Processes the given data (may change the provided dataset) and returns the modified version.
* This method is called in batchFinished().
*
* @param instances the data to process
* @return the modified data
* @throws Exception in case the processing goes wrong
* @see #batchFinished()
*/
protected Instances process(Instances instances) throws Exception {
Instances result;
int i;
int n;
double[] values;
String value;
Instance inst;
Instance newInst;
// we need the complete input data!
if (!isFirstBatchDone()) setOutputFormat(determineOutputFormat(getInputFormat()));
result = new Instances(getOutputFormat());
for (i = 0; i < instances.numInstances(); i++) {
inst = instances.instance(i);
values = inst.toDoubleArray();
for (n = 0; n < values.length; n++) {
if (!m_Cols.isInRange(n) || !instances.attribute(n).isNumeric() || inst.isMissing(n))
continue;
// get index of value
if (instances.attribute(n).type() == Attribute.DATE) value = inst.stringValue(n);
else value = Utils.doubleToString(inst.value(n), MAX_DECIMALS);
values[n] = result.attribute(n).indexOfValue(value);
}
// generate new instance
if (inst instanceof SparseInstance) newInst = new SparseInstance(inst.weight(), values);
else newInst = new DenseInstance(inst.weight(), values);
// copy possible string, relational values
newInst.setDataset(getOutputFormat());
copyValues(newInst, false, inst.dataset(), getOutputFormat());
result.add(newInst);
}
return result;
}
/**
* Updates the minimum and maximum and width values for all the attributes based on a new
* instance.
*
* @param instance the new instance
* @param numAtt number of attributes in the model
* @param ranges low, high and width values for all attributes
*/
public void updateRanges(Instance instance, int numAtt, double[][] ranges) {
// updateRangesFirst must have been called on ranges
for (int j = 0; j < numAtt; j++) {
double value = instance.value(j);
if (!instance.isMissing(j)) {
if (value < ranges[j][R_MIN]) {
ranges[j][R_MIN] = value;
ranges[j][R_WIDTH] = ranges[j][R_MAX] - ranges[j][R_MIN];
if (value > ranges[j][R_MAX]) { // if this is the first value that is
ranges[j][R_MAX] = value; // not missing. The,0
ranges[j][R_WIDTH] = ranges[j][R_MAX] - ranges[j][R_MIN];
}
} else {
if (value > ranges[j][R_MAX]) {
ranges[j][R_MAX] = value;
ranges[j][R_WIDTH] = ranges[j][R_MAX] - ranges[j][R_MIN];
}
}
}
}
}
/**
* Implements the splitData function. This procedure is to split the data into bags according to
* the nominal attribute value The infoGain for each bag is also calculated.
*
* @param data the data to be split
* @param defAcRt the default accuracy rate for data
* @param cl the class label to be predicted
* @return the array of data after split
*/
public Instances[] splitData(Instances data, double defAcRt, double cl) {
int bag = att.numValues();
Instances[] splitData = new Instances[bag];
for (int x = 0; x < bag; x++) {
splitData[x] = new Instances(data, data.numInstances());
accurate[x] = 0;
coverage[x] = 0;
}
for (int x = 0; x < data.numInstances(); x++) {
Instance inst = data.instance(x);
if (!inst.isMissing(att)) {
int v = (int) inst.value(att);
splitData[v].add(inst);
coverage[v] += inst.weight();
if ((int) inst.classValue() == (int) cl) accurate[v] += inst.weight();
}
}
for (int x = 0; x < bag; x++) {
double t = coverage[x] + 1.0;
double p = accurate[x] + 1.0;
double infoGain =
// Utils.eq(defAcRt, 1.0) ?
// accurate[x]/(double)numConds :
accurate[x] * (Utils.log2(p / t) - Utils.log2(defAcRt));
if (infoGain > maxInfoGain) {
maxInfoGain = infoGain;
cover = coverage[x];
accu = accurate[x];
accuRate = p / t;
value = (double) x;
}
}
return splitData;
}
/** if clusterIdx is -1, all instances are used (a single metric for all clusters is used) */
public boolean trainMetric(int clusterIdx) throws Exception {
Init(clusterIdx);
double[] weights = new double[m_numAttributes];
int violatedConstraints = 0;
int numInstances = 0;
for (int instIdx = 0; instIdx < m_instances.numInstances(); instIdx++) {
int assignment = m_clusterAssignments[instIdx];
// only instances assigned to this cluster are of importance
if (assignment == clusterIdx || clusterIdx == -1) {
numInstances++;
if (clusterIdx < 0) {
m_centroid = m_kmeans.getClusterCentroids().instance(assignment);
}
// accumulate variance
Instance instance = m_instances.instance(instIdx);
Instance diffInstance = m_metric.createDiffInstance(instance, m_centroid);
for (int attr = 0; attr < m_numAttributes; attr++) {
weights[attr] += diffInstance.value(attr);
}
// check all constraints for this instance
Object list = m_instanceConstraintMap.get(new Integer(instIdx));
if (list != null) { // there are constraints associated with this instance
ArrayList constraintList = (ArrayList) list;
for (int i = 0; i < constraintList.size(); i++) {
InstancePair pair = (InstancePair) constraintList.get(i);
int linkType = pair.linkType;
int firstIdx = pair.first;
int secondIdx = pair.second;
Instance instance1 = m_instances.instance(firstIdx);
Instance instance2 = m_instances.instance(secondIdx);
int otherIdx =
(firstIdx == instIdx)
? m_clusterAssignments[secondIdx]
: m_clusterAssignments[firstIdx];
if (otherIdx != -1) { // check whether the constraint is violated
if (otherIdx != assignment && linkType == InstancePair.MUST_LINK) {
diffInstance = m_metric.createDiffInstance(instance1, instance2);
for (int attr = 0; attr < m_numAttributes; attr++) {
weights[attr] += 0.5 * m_MLweight * diffInstance.value(attr);
}
} else if (otherIdx == assignment && linkType == InstancePair.CANNOT_LINK) {
diffInstance = m_metric.createDiffInstance(instance1, instance2);
for (int attr = 0; attr < m_numAttributes; attr++) {
// this constraint will be counted twice, hence 0.5
weights[attr] += 0.5 * m_CLweight * m_maxCLDiffInstance.value(attr);
weights[attr] -= 0.5 * m_CLweight * diffInstance.value(attr);
}
}
}
}
}
}
}
// System.out.println("Updating cluster " + clusterIdx
// + " containing " + numInstances);
// check the weights
double[] newWeights = new double[m_numAttributes];
double[] currentWeights = m_metric.getWeights();
boolean needNewtonRaphson = false;
for (int attr = 0; attr < m_numAttributes; attr++) {
if (weights[attr] <= 0) { // check to avoid divide by 0 - TODO!
System.out.println(
"Negative weight "
+ weights[attr]
+ " for clusterIdx="
+ clusterIdx
+ "; using prev value="
+ currentWeights[attr]);
newWeights[attr] = currentWeights[attr];
// needNewtonRaphson = true;
// break;
} else {
if (m_regularize) { // solution of quadratic equation - TODO!
int n = m_instances.numInstances();
double ratio = (m_logTermWeight * n) / (2 * weights[attr]);
newWeights[attr] =
ratio + Math.sqrt(ratio * ratio + (m_regularizerTermWeight * n) / weights[attr]);
} else {
newWeights[attr] = m_logTermWeight * numInstances / weights[attr];
}
}
}
// do NR if needed
if (needNewtonRaphson) {
System.out.println("GOING TO NEWTON-RAPHSON!!!\n");
newWeights = updateWeightsUsingNewtonRaphson(currentWeights, weights);
}
// PRINT routine
// System.out.println("Total constraints violated: " + violatedConstraints/2 + "; weights
// are:");
// for (int attr=0; attr<numAttributes; attr++) {
// System.out.print(newWeights[attr] + "\t");
// }
// System.out.println();
// end PRINT routine
m_metric.setWeights(newWeights);
return true;
}
/**
* Saves an instances incrementally. Structure has to be set by using the setStructure() method or
* setInstances() method.
*
* @param inst the instance to save
* @throws IOException throws IOEXception if an instance cannot be saved incrementally.
*/
public void writeIncremental(Instance inst) throws IOException {
int writeMode = getWriteMode();
Instances structure = getInstances();
PrintWriter outW = null;
if (structure != null) {
if (structure.classIndex() == -1) {
structure.setClassIndex(structure.numAttributes() - 1);
System.err.println("No class specified. Last attribute is used as class attribute.");
}
if (structure.attribute(structure.classIndex()).isNumeric())
throw new IOException("To save in C4.5 format the class attribute cannot be numeric.");
}
if (getRetrieval() == BATCH || getRetrieval() == NONE)
throw new IOException("Batch and incremental saving cannot be mixed.");
if (retrieveFile() == null || getWriter() == null) {
throw new IOException(
"C4.5 format requires two files. Therefore no output to standard out can be generated.\nPlease specifiy output files using the -o option.");
}
outW = new PrintWriter(getWriter());
if (writeMode == WAIT) {
if (structure == null) {
setWriteMode(CANCEL);
if (inst != null)
System.err.println("Structure(Header Information) has to be set in advance");
} else setWriteMode(STRUCTURE_READY);
writeMode = getWriteMode();
}
if (writeMode == CANCEL) {
if (outW != null) outW.close();
cancel();
}
if (writeMode == STRUCTURE_READY) {
setWriteMode(WRITE);
// write header: here names file
for (int i = 0; i < structure.attribute(structure.classIndex()).numValues(); i++) {
outW.write(structure.attribute(structure.classIndex()).value(i));
if (i < structure.attribute(structure.classIndex()).numValues() - 1) {
outW.write(",");
} else {
outW.write(".\n");
}
}
for (int i = 0; i < structure.numAttributes(); i++) {
if (i != structure.classIndex()) {
outW.write(structure.attribute(i).name() + ": ");
if (structure.attribute(i).isNumeric() || structure.attribute(i).isDate()) {
outW.write("continuous.\n");
} else {
Attribute temp = structure.attribute(i);
for (int j = 0; j < temp.numValues(); j++) {
outW.write(temp.value(j));
if (j < temp.numValues() - 1) {
outW.write(",");
} else {
outW.write(".\n");
}
}
}
}
}
outW.flush();
outW.close();
writeMode = getWriteMode();
String out = retrieveFile().getAbsolutePath();
setFileExtension(".data");
out = out.substring(0, out.lastIndexOf('.')) + getFileExtension();
File namesFile = new File(out);
try {
setFile(namesFile);
} catch (Exception ex) {
throw new IOException("Cannot create data file, only names file created.");
}
if (retrieveFile() == null || getWriter() == null) {
throw new IOException("Cannot create data file, only names file created.");
}
outW = new PrintWriter(getWriter());
}
if (writeMode == WRITE) {
if (structure == null) throw new IOException("No instances information available.");
if (inst != null) {
// write instance: here data file
for (int j = 0; j < inst.numAttributes(); j++) {
if (j != structure.classIndex()) {
if (inst.isMissing(j)) {
outW.write("?,");
} else if (structure.attribute(j).isNominal() || structure.attribute(j).isString()) {
outW.write(structure.attribute(j).value((int) inst.value(j)) + ",");
} else {
outW.write("" + inst.value(j) + ",");
}
}
}
// write the class value
if (inst.isMissing(structure.classIndex())) {
outW.write("?");
} else {
outW.write(
structure
.attribute(structure.classIndex())
.value((int) inst.value(structure.classIndex())));
}
outW.write("\n");
// flushes every 100 instances
m_incrementalCounter++;
if (m_incrementalCounter > 100) {
m_incrementalCounter = 0;
outW.flush();
}
} else {
// close
if (outW != null) {
outW.flush();
outW.close();
}
setFileExtension(".names");
m_incrementalCounter = 0;
resetStructure();
outW = null;
resetWriter();
}
}
}
/**
* Writes a Batch of instances
*
* @throws IOException throws IOException if saving in batch mode is not possible
*/
public void writeBatch() throws IOException {
Instances instances = getInstances();
if (instances == null) throw new IOException("No instances to save");
if (instances.classIndex() == -1) {
instances.setClassIndex(instances.numAttributes() - 1);
System.err.println("No class specified. Last attribute is used as class attribute.");
}
if (instances.attribute(instances.classIndex()).isNumeric())
throw new IOException("To save in C4.5 format the class attribute cannot be numeric.");
if (getRetrieval() == INCREMENTAL)
throw new IOException("Batch and incremental saving cannot be mixed.");
setRetrieval(BATCH);
if (retrieveFile() == null || getWriter() == null) {
throw new IOException(
"C4.5 format requires two files. Therefore no output to standard out can be generated.\nPlease specifiy output files using the -o option.");
}
setWriteMode(WRITE);
// print names file
setFileExtension(".names");
PrintWriter outW = new PrintWriter(getWriter());
for (int i = 0; i < instances.attribute(instances.classIndex()).numValues(); i++) {
outW.write(instances.attribute(instances.classIndex()).value(i));
if (i < instances.attribute(instances.classIndex()).numValues() - 1) {
outW.write(",");
} else {
outW.write(".\n");
}
}
for (int i = 0; i < instances.numAttributes(); i++) {
if (i != instances.classIndex()) {
outW.write(instances.attribute(i).name() + ": ");
if (instances.attribute(i).isNumeric() || instances.attribute(i).isDate()) {
outW.write("continuous.\n");
} else {
Attribute temp = instances.attribute(i);
for (int j = 0; j < temp.numValues(); j++) {
outW.write(temp.value(j));
if (j < temp.numValues() - 1) {
outW.write(",");
} else {
outW.write(".\n");
}
}
}
}
}
outW.flush();
outW.close();
// print data file
String out = retrieveFile().getAbsolutePath();
setFileExtension(".data");
out = out.substring(0, out.lastIndexOf('.')) + getFileExtension();
File namesFile = new File(out);
try {
setFile(namesFile);
} catch (Exception ex) {
throw new IOException(
"Cannot create data file, only names file created (Reason: " + ex.toString() + ").");
}
if (retrieveFile() == null || getWriter() == null) {
throw new IOException("Cannot create data file, only names file created.");
}
outW = new PrintWriter(getWriter());
// print data file
for (int i = 0; i < instances.numInstances(); i++) {
Instance temp = instances.instance(i);
for (int j = 0; j < temp.numAttributes(); j++) {
if (j != instances.classIndex()) {
if (temp.isMissing(j)) {
outW.write("?,");
} else if (instances.attribute(j).isNominal() || instances.attribute(j).isString()) {
outW.write(instances.attribute(j).value((int) temp.value(j)) + ",");
} else {
outW.write("" + temp.value(j) + ",");
}
}
}
// write the class value
if (temp.isMissing(instances.classIndex())) {
outW.write("?");
} else {
outW.write(
instances
.attribute(instances.classIndex())
.value((int) temp.value(instances.classIndex())));
}
outW.write("\n");
}
outW.flush();
outW.close();
setFileExtension(".names");
setWriteMode(WAIT);
outW = null;
resetWriter();
setWriteMode(CANCEL);
}
/**
* Evaluates a feature subset by cross validation
*
* @param feature_set the subset to be evaluated
* @param num_atts the number of attributes in the subset
* @return the estimated accuracy
* @throws Exception if subset can't be evaluated
*/
protected double estimatePerformance(BitSet feature_set, int num_atts) throws Exception {
m_evaluation = new Evaluation(m_theInstances);
int i;
int[] fs = new int[num_atts];
double[] instA = new double[num_atts];
int classI = m_theInstances.classIndex();
int index = 0;
for (i = 0; i < m_numAttributes; i++) {
if (feature_set.get(i)) {
fs[index++] = i;
}
}
// create new hash table
m_entries = new Hashtable((int) (m_theInstances.numInstances() * 1.5));
// insert instances into the hash table
for (i = 0; i < m_numInstances; i++) {
Instance inst = m_theInstances.instance(i);
for (int j = 0; j < fs.length; j++) {
if (fs[j] == classI) {
instA[j] = Double.MAX_VALUE; // missing for the class
} else if (inst.isMissing(fs[j])) {
instA[j] = Double.MAX_VALUE;
} else {
instA[j] = inst.value(fs[j]);
}
}
insertIntoTable(inst, instA);
}
if (m_CVFolds == 1) {
// calculate leave one out error
for (i = 0; i < m_numInstances; i++) {
Instance inst = m_theInstances.instance(i);
for (int j = 0; j < fs.length; j++) {
if (fs[j] == classI) {
instA[j] = Double.MAX_VALUE; // missing for the class
} else if (inst.isMissing(fs[j])) {
instA[j] = Double.MAX_VALUE;
} else {
instA[j] = inst.value(fs[j]);
}
}
evaluateInstanceLeaveOneOut(inst, instA);
}
} else {
m_theInstances.randomize(m_rr);
m_theInstances.stratify(m_CVFolds);
// calculate 10 fold cross validation error
for (i = 0; i < m_CVFolds; i++) {
Instances insts = m_theInstances.testCV(m_CVFolds, i);
evaluateFoldCV(insts, fs);
}
}
switch (m_evaluationMeasure) {
case EVAL_DEFAULT:
if (m_classIsNominal) {
return m_evaluation.pctCorrect();
}
return -m_evaluation.rootMeanSquaredError();
case EVAL_ACCURACY:
return m_evaluation.pctCorrect();
case EVAL_RMSE:
return -m_evaluation.rootMeanSquaredError();
case EVAL_MAE:
return -m_evaluation.meanAbsoluteError();
case EVAL_AUC:
double[] classPriors = m_evaluation.getClassPriors();
Utils.normalize(classPriors);
double weightedAUC = 0;
for (i = 0; i < m_theInstances.classAttribute().numValues(); i++) {
double tempAUC = m_evaluation.areaUnderROC(i);
if (!Utils.isMissingValue(tempAUC)) {
weightedAUC += (classPriors[i] * tempAUC);
} else {
System.err.println("Undefined AUC!!");
}
}
return weightedAUC;
}
// shouldn't get here
return 0.0;
}
/**
* evaluates an individual attribute by measuring the gain ratio of the class given the attribute.
*
* @param attribute the index of the attribute to be evaluated
* @return the gain ratio
* @throws Exception if the attribute could not be evaluated
*/
public double evaluateAttribute(int attribute) throws Exception {
int i, j, ii, jj;
int ni, nj;
double sum = 0.0;
ni = m_trainInstances.attribute(attribute).numValues() + 1;
nj = m_numClasses + 1;
double[] sumi, sumj;
Instance inst;
double temp = 0.0;
sumi = new double[ni];
sumj = new double[nj];
double[][] counts = new double[ni][nj];
sumi = new double[ni];
sumj = new double[nj];
for (i = 0; i < ni; i++) {
sumi[i] = 0.0;
for (j = 0; j < nj; j++) {
sumj[j] = 0.0;
counts[i][j] = 0.0;
}
}
// Fill the contingency table
for (i = 0; i < m_numInstances; i++) {
inst = m_trainInstances.instance(i);
if (inst.isMissing(attribute)) {
ii = ni - 1;
} else {
ii = (int) inst.value(attribute);
}
if (inst.isMissing(m_classIndex)) {
jj = nj - 1;
} else {
jj = (int) inst.value(m_classIndex);
}
counts[ii][jj]++;
}
// get the row totals
for (i = 0; i < ni; i++) {
sumi[i] = 0.0;
for (j = 0; j < nj; j++) {
sumi[i] += counts[i][j];
sum += counts[i][j];
}
}
// get the column totals
for (j = 0; j < nj; j++) {
sumj[j] = 0.0;
for (i = 0; i < ni; i++) {
sumj[j] += counts[i][j];
}
}
// distribute missing counts
if (m_missing_merge && (sumi[ni - 1] < m_numInstances) && (sumj[nj - 1] < m_numInstances)) {
double[] i_copy = new double[sumi.length];
double[] j_copy = new double[sumj.length];
double[][] counts_copy = new double[sumi.length][sumj.length];
for (i = 0; i < ni; i++) {
System.arraycopy(counts[i], 0, counts_copy[i], 0, sumj.length);
}
System.arraycopy(sumi, 0, i_copy, 0, sumi.length);
System.arraycopy(sumj, 0, j_copy, 0, sumj.length);
double total_missing = (sumi[ni - 1] + sumj[nj - 1] - counts[ni - 1][nj - 1]);
// do the missing i's
if (sumi[ni - 1] > 0.0) {
for (j = 0; j < nj - 1; j++) {
if (counts[ni - 1][j] > 0.0) {
for (i = 0; i < ni - 1; i++) {
temp = ((i_copy[i] / (sum - i_copy[ni - 1])) * counts[ni - 1][j]);
counts[i][j] += temp;
sumi[i] += temp;
}
counts[ni - 1][j] = 0.0;
}
}
}
sumi[ni - 1] = 0.0;
// do the missing j's
if (sumj[nj - 1] > 0.0) {
for (i = 0; i < ni - 1; i++) {
if (counts[i][nj - 1] > 0.0) {
for (j = 0; j < nj - 1; j++) {
temp = ((j_copy[j] / (sum - j_copy[nj - 1])) * counts[i][nj - 1]);
counts[i][j] += temp;
sumj[j] += temp;
}
counts[i][nj - 1] = 0.0;
}
}
}
sumj[nj - 1] = 0.0;
// do the both missing
if (counts[ni - 1][nj - 1] > 0.0 && total_missing != sum) {
for (i = 0; i < ni - 1; i++) {
for (j = 0; j < nj - 1; j++) {
temp = (counts_copy[i][j] / (sum - total_missing)) * counts_copy[ni - 1][nj - 1];
counts[i][j] += temp;
sumi[i] += temp;
sumj[j] += temp;
}
}
counts[ni - 1][nj - 1] = 0.0;
}
}
return ContingencyTables.gainRatio(counts);
}
/**
* Returns true if the value of the given dimension is smaller or equal the value to be compared
* with.
*
* @param instance the instance where the value should be taken of
* @param dim the dimension of the value
* @param value the value to compare with
* @return true if value of instance is smaller or equal value
*/
public boolean valueIsSmallerEqual(Instance instance, int dim, double value) { // This stays
return instance.value(dim) <= value;
}
/**
* Gets the index of the branch that an instance applies to. Returns -1 if no branches apply.
*
* @param i the instance
* @return the branch index
*/
public int branchInstanceGoesDown(Instance inst) {
if (inst.isMissing(attIndex)) return -1;
else if (inst.value(attIndex) < splitPoint) return 0;
else return 1;
}
public void buildClassifier(Instances insts) throws Exception {
// Compute mean of target value
double yMean = insts.meanOrMode(insts.classIndex());
// Choose best attribute
double minMsq = Double.MAX_VALUE;
m_attribute = null;
int chosen = -1;
double chosenSlope = Double.NaN;
double chosenIntercept = Double.NaN;
for (int i = 0; i < insts.numAttributes(); i++) {
if (i != insts.classIndex()) {
if (!insts.attribute(i).isNumeric()) {
throw new Exception("UnivariateLinearRegression: Only numeric attributes!");
}
m_attribute = insts.attribute(i);
// Compute slope and intercept
double xMean = insts.meanOrMode(i);
double sumWeightedXDiffSquared = 0;
double sumWeightedYDiffSquared = 0;
m_slope = 0;
for (int j = 0; j < insts.numInstances(); j++) {
Instance inst = insts.instance(j);
if (!inst.isMissing(i) && !inst.classIsMissing()) {
double xDiff = inst.value(i) - xMean;
double yDiff = inst.classValue() - yMean;
double weightedXDiff = inst.weight() * xDiff;
double weightedYDiff = inst.weight() * yDiff;
m_slope += weightedXDiff * yDiff;
sumWeightedXDiffSquared += weightedXDiff * xDiff;
sumWeightedYDiffSquared += weightedYDiff * yDiff;
}
}
// Skip attribute if not useful
if (sumWeightedXDiffSquared == 0) {
continue;
}
double numerator = m_slope;
m_slope /= sumWeightedXDiffSquared;
m_intercept = yMean - m_slope * xMean;
// Compute sum of squared errors
double msq = sumWeightedYDiffSquared - m_slope * numerator;
// Check whether this is the best attribute
if (msq < minMsq) {
minMsq = msq;
chosen = i;
chosenSlope = m_slope;
chosenIntercept = m_intercept;
}
}
}
// Set parameters
if (chosen == -1) {
System.err.println("----- no useful attribute found");
m_attribute = null;
m_slope = 0;
m_intercept = yMean;
} else {
m_attribute = insts.attribute(chosen);
m_slope = chosenSlope;
m_intercept = chosenIntercept;
}
}
/**
* Calculates the accuracy on a test fold for internal cross validation of feature sets
*
* @param fold set of instances to be "left out" and classified
* @param fs currently selected feature set
* @return the accuracy for the fold
* @throws Exception if something goes wrong
*/
double evaluateFoldCV(Instances fold, int[] fs) throws Exception {
int i;
int ruleCount = 0;
int numFold = fold.numInstances();
int numCl = m_theInstances.classAttribute().numValues();
double[][] class_distribs = new double[numFold][numCl];
double[] instA = new double[fs.length];
double[] normDist;
DecisionTableHashKey thekey;
double acc = 0.0;
int classI = m_theInstances.classIndex();
Instance inst;
if (m_classIsNominal) {
normDist = new double[numCl];
} else {
normDist = new double[2];
}
// first *remove* instances
for (i = 0; i < numFold; i++) {
inst = fold.instance(i);
for (int j = 0; j < fs.length; j++) {
if (fs[j] == classI) {
instA[j] = Double.MAX_VALUE; // missing for the class
} else if (inst.isMissing(fs[j])) {
instA[j] = Double.MAX_VALUE;
} else {
instA[j] = inst.value(fs[j]);
}
}
thekey = new DecisionTableHashKey(instA);
if ((class_distribs[i] = (double[]) m_entries.get(thekey)) == null) {
throw new Error("This should never happen!");
} else {
if (m_classIsNominal) {
class_distribs[i][(int) inst.classValue()] -= inst.weight();
} else {
class_distribs[i][0] -= (inst.classValue() * inst.weight());
class_distribs[i][1] -= inst.weight();
}
ruleCount++;
}
m_classPriorCounts[(int) inst.classValue()] -= inst.weight();
}
double[] classPriors = m_classPriorCounts.clone();
Utils.normalize(classPriors);
// now classify instances
for (i = 0; i < numFold; i++) {
inst = fold.instance(i);
System.arraycopy(class_distribs[i], 0, normDist, 0, normDist.length);
if (m_classIsNominal) {
boolean ok = false;
for (int j = 0; j < normDist.length; j++) {
if (Utils.gr(normDist[j], 1.0)) {
ok = true;
break;
}
}
if (!ok) { // majority class
normDist = classPriors.clone();
}
// if (ok) {
Utils.normalize(normDist);
if (m_evaluationMeasure == EVAL_AUC) {
m_evaluation.evaluateModelOnceAndRecordPrediction(normDist, inst);
} else {
m_evaluation.evaluateModelOnce(normDist, inst);
}
/* } else {
normDist[(int)m_majority] = 1.0;
if (m_evaluationMeasure == EVAL_AUC) {
m_evaluation.evaluateModelOnceAndRecordPrediction(normDist, inst);
} else {
m_evaluation.evaluateModelOnce(normDist, inst);
}
} */
} else {
if (Utils.eq(normDist[1], 0.0)) {
double[] temp = new double[1];
temp[0] = m_majority;
m_evaluation.evaluateModelOnce(temp, inst);
} else {
double[] temp = new double[1];
temp[0] = normDist[0] / normDist[1];
m_evaluation.evaluateModelOnce(temp, inst);
}
}
}
// now re-insert instances
for (i = 0; i < numFold; i++) {
inst = fold.instance(i);
m_classPriorCounts[(int) inst.classValue()] += inst.weight();
if (m_classIsNominal) {
class_distribs[i][(int) inst.classValue()] += inst.weight();
} else {
class_distribs[i][0] += (inst.classValue() * inst.weight());
class_distribs[i][1] += inst.weight();
}
}
return acc;
}