/*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* Discretize.java
* Copyright (C) 1999-2012 University of Waikato, Hamilton, New Zealand
*
*/
package weka.filters.supervised.attribute;
import java.util.Enumeration;
import java.util.Vector;
import weka.core.Attribute;
import weka.core.Capabilities;
import weka.core.Capabilities.Capability;
import weka.core.ContingencyTables;
import weka.core.DenseInstance;
import weka.core.FastVector;
import weka.core.Instance;
import weka.core.Instances;
import weka.core.Option;
import weka.core.OptionHandler;
import weka.core.ProtectedProperties;
import weka.core.Range;
import weka.core.RevisionUtils;
import weka.core.SparseInstance;
import weka.core.SpecialFunctions;
import weka.core.TechnicalInformation;
import weka.core.TechnicalInformation.Field;
import weka.core.TechnicalInformation.Type;
import weka.core.TechnicalInformationHandler;
import weka.core.Utils;
import weka.core.WeightedInstancesHandler;
import weka.filters.Filter;
import weka.filters.SupervisedFilter;
/**
<!-- globalinfo-start -->
* An instance filter that discretizes a range of numeric attributes in the dataset into nominal attributes. Discretization is by Fayyad & Irani's MDL method (the default).<br/>
* <br/>
* For more information, see:<br/>
* <br/>
* Usama M. Fayyad, Keki B. Irani: Multi-interval discretization of continuousvalued attributes for classification learning. In: Thirteenth International Joint Conference on Articial Intelligence, 1022-1027, 1993.<br/>
* <br/>
* Igor Kononenko: On Biases in Estimating Multi-Valued Attributes. In: 14th International Joint Conference on Articial Intelligence, 1034-1040, 1995.
* <p/>
<!-- globalinfo-end -->
*
<!-- technical-bibtex-start -->
* BibTeX:
* <pre>
* @inproceedings{Fayyad1993,
* author = {Usama M. Fayyad and Keki B. Irani},
* booktitle = {Thirteenth International Joint Conference on Articial Intelligence},
* pages = {1022-1027},
* publisher = {Morgan Kaufmann Publishers},
* title = {Multi-interval discretization of continuousvalued attributes for classification learning},
* volume = {2},
* year = {1993}
* }
*
* @inproceedings{Kononenko1995,
* author = {Igor Kononenko},
* booktitle = {14th International Joint Conference on Articial Intelligence},
* pages = {1034-1040},
* title = {On Biases in Estimating Multi-Valued Attributes},
* year = {1995},
* PS = {http://ai.fri.uni-lj.si/papers/kononenko95-ijcai.ps.gz}
* }
* </pre>
* <p/>
<!-- technical-bibtex-end -->
*
<!-- options-start -->
* Valid options are: <p/>
*
* <pre> -R <col1,col2-col4,...>
* Specifies list of columns to Discretize. First and last are valid indexes.
* (default none)</pre>
*
* <pre> -V
* Invert matching sense of column indexes.</pre>
*
* <pre> -D
* Output binary attributes for discretized attributes.</pre>
*
* <pre> -Y
* Use bin numbers rather than ranges for discretized attributes.</pre>
*
* <pre> -E
* Use better encoding of split point for MDL.</pre>
*
* <pre> -K
* Use Kononenko's MDL criterion.</pre>
*
<!-- options-end -->
*
* @author Len Trigg (trigg@cs.waikato.ac.nz)
* @author Eibe Frank (eibe@cs.waikato.ac.nz)
* @version $Revision: 9088 $
*/
public class Discretize
extends Filter
implements SupervisedFilter, OptionHandler, WeightedInstancesHandler,
TechnicalInformationHandler {
/** for serialization */
static final long serialVersionUID = -3141006402280129097L;
/** Stores which columns to Discretize */
protected Range m_DiscretizeCols = new Range();
/** Store the current cutpoints */
protected double [][] m_CutPoints = null;
/** Output binary attributes for discretized attributes. */
protected boolean m_MakeBinary = false;
/** Use bin numbers rather than ranges for discretized attributes. */
protected boolean m_UseBinNumbers = false;
/** Use better encoding of split point for MDL. */
protected boolean m_UseBetterEncoding = false;
/** Use Kononenko's MDL criterion instead of Fayyad et al.'s */
protected boolean m_UseKononenko = false;
/** Constructor - initialises the filter */
public Discretize() {
setAttributeIndices("first-last");
}
/**
* Gets an enumeration describing the available options.
*
* @return an enumeration of all the available options.
*/
public Enumeration listOptions() {
Vector newVector = new Vector(7);
newVector.addElement(new Option(
"\tSpecifies list of columns to Discretize. First"
+ " and last are valid indexes.\n"
+ "\t(default none)",
"R", 1, "-R <col1,col2-col4,...>"));
newVector.addElement(new Option(
"\tInvert matching sense of column indexes.",
"V", 0, "-V"));
newVector.addElement(new Option(
"\tOutput binary attributes for discretized attributes.",
"D", 0, "-D"));
newVector.addElement(new Option(
"\tUse bin numbers rather than ranges for discretized attributes.",
"Y", 0, "-Y"));
newVector.addElement(new Option(
"\tUse better encoding of split point for MDL.",
"E", 0, "-E"));
newVector.addElement(new Option(
"\tUse Kononenko's MDL criterion.",
"K", 0, "-K"));
return newVector.elements();
}
/**
* Parses a given list of options. <p/>
*
<!-- options-start -->
* Valid options are: <p/>
*
* <pre> -R <col1,col2-col4,...>
* Specifies list of columns to Discretize. First and last are valid indexes.
* (default none)</pre>
*
* <pre> -V
* Invert matching sense of column indexes.</pre>
*
* <pre> -D
* Output binary attributes for discretized attributes.</pre>
*
* <pre> -Y
* Use bin numbers rather than ranges for discretized attributes.</pre>
*
* <pre> -E
* Use better encoding of split point for MDL.</pre>
*
* <pre> -K
* Use Kononenko's MDL criterion.</pre>
*
<!-- options-end -->
*
* @param options the list of options as an array of strings
* @throws Exception if an option is not supported
*/
public void setOptions(String[] options) throws Exception {
setMakeBinary(Utils.getFlag('D', options));
setUseBinNumbers(Utils.getFlag('Y', options));
setUseBetterEncoding(Utils.getFlag('E', options));
setUseKononenko(Utils.getFlag('K', options));
setInvertSelection(Utils.getFlag('V', options));
String convertList = Utils.getOption('R', options);
if (convertList.length() != 0) {
setAttributeIndices(convertList);
} else {
setAttributeIndices("first-last");
}
if (getInputFormat() != null) {
setInputFormat(getInputFormat());
}
}
/**
* Gets the current settings of the filter.
*
* @return an array of strings suitable for passing to setOptions
*/
public String [] getOptions() {
String [] options = new String [12];
int current = 0;
if (getMakeBinary()) {
options[current++] = "-D";
}
if (getUseBinNumbers()) {
options[current++] = "-Y";
}
if (getUseBetterEncoding()) {
options[current++] = "-E";
}
if (getUseKononenko()) {
options[current++] = "-K";
}
if (getInvertSelection()) {
options[current++] = "-V";
}
if (!getAttributeIndices().equals("")) {
options[current++] = "-R"; options[current++] = getAttributeIndices();
}
while (current < options.length) {
options[current++] = "";
}
return options;
}
/**
* Returns the Capabilities of this filter.
*
* @return the capabilities of this object
* @see Capabilities
*/
public Capabilities getCapabilities() {
Capabilities result = super.getCapabilities();
result.disableAll();
// attributes
result.enableAllAttributes();
result.enable(Capability.MISSING_VALUES);
// class
result.enable(Capability.NOMINAL_CLASS);
return result;
}
/**
* Sets the format of the input instances.
*
* @param instanceInfo an Instances object containing the input instance
* structure (any instances contained in the object are ignored - only the
* structure is required).
* @return true if the outputFormat may be collected immediately
* @throws Exception if the input format can't be set successfully
*/
public boolean setInputFormat(Instances instanceInfo) throws Exception {
super.setInputFormat(instanceInfo);
m_DiscretizeCols.setUpper(instanceInfo.numAttributes() - 1);
m_CutPoints = null;
// If we implement loading cutfiles, then load
//them here and set the output format
return false;
}
/**
* Input an instance for filtering. Ordinarily the instance is processed
* and made available for output immediately. Some filters require all
* instances be read before producing output.
*
* @param instance the input instance
* @return true if the filtered instance may now be
* collected with output().
* @throws IllegalStateException if no input format has been defined.
*/
public boolean input(Instance instance) {
if (getInputFormat() == null) {
throw new IllegalStateException("No input instance format defined");
}
if (m_NewBatch) {
resetQueue();
m_NewBatch = false;
}
if (m_CutPoints != null) {
convertInstance(instance);
return true;
}
bufferInput(instance);
return false;
}
/**
* Signifies that this batch of input to the filter is finished. If the
* filter requires all instances prior to filtering, output() may now
* be called to retrieve the filtered instances.
*
* @return true if there are instances pending output
* @throws IllegalStateException if no input structure has been defined
*/
public boolean batchFinished() {
if (getInputFormat() == null) {
throw new IllegalStateException("No input instance format defined");
}
if (m_CutPoints == null) {
calculateCutPoints();
setOutputFormat();
// If we implement saving cutfiles, save the cuts here
// Convert pending input instances
for(int i = 0; i < getInputFormat().numInstances(); i++) {
convertInstance(getInputFormat().instance(i));
}
}
flushInput();
m_NewBatch = true;
return (numPendingOutput() != 0);
}
/**
* Returns a string describing this filter
*
* @return a description of the filter suitable for
* displaying in the explorer/experimenter gui
*/
public String globalInfo() {
return "An instance filter that discretizes a range of numeric"
+ " attributes in the dataset into nominal attributes."
+ " Discretization is by Fayyad & Irani's MDL method (the default).\n\n"
+ "For more information, see:\n\n"
+ getTechnicalInformation().toString();
}
/**
* Returns an instance of a TechnicalInformation object, containing
* detailed information about the technical background of this class,
* e.g., paper reference or book this class is based on.
*
* @return the technical information about this class
*/
public TechnicalInformation getTechnicalInformation() {
TechnicalInformation result;
TechnicalInformation additional;
result = new TechnicalInformation(Type.INPROCEEDINGS);
result.setValue(Field.AUTHOR, "Usama M. Fayyad and Keki B. Irani");
result.setValue(Field.TITLE, "Multi-interval discretization of continuousvalued attributes for classification learning");
result.setValue(Field.BOOKTITLE, "Thirteenth International Joint Conference on Articial Intelligence");
result.setValue(Field.YEAR, "1993");
result.setValue(Field.VOLUME, "2");
result.setValue(Field.PAGES, "1022-1027");
result.setValue(Field.PUBLISHER, "Morgan Kaufmann Publishers");
additional = result.add(Type.INPROCEEDINGS);
additional.setValue(Field.AUTHOR, "Igor Kononenko");
additional.setValue(Field.TITLE, "On Biases in Estimating Multi-Valued Attributes");
additional.setValue(Field.BOOKTITLE, "14th International Joint Conference on Articial Intelligence");
additional.setValue(Field.YEAR, "1995");
additional.setValue(Field.PAGES, "1034-1040");
additional.setValue(Field.PS, "http://ai.fri.uni-lj.si/papers/kononenko95-ijcai.ps.gz");
return result;
}
/**
* Returns the tip text for this property
*
* @return tip text for this property suitable for
* displaying in the explorer/experimenter gui
*/
public String makeBinaryTipText() {
return "Make resulting attributes binary.";
}
/**
* Gets whether binary attributes should be made for discretized ones.
*
* @return true if attributes will be binarized
*/
public boolean getMakeBinary() {
return m_MakeBinary;
}
/**
* Sets whether binary attributes should be made for discretized ones.
*
* @param makeBinary if binary attributes are to be made
*/
public void setMakeBinary(boolean makeBinary) {
m_MakeBinary = makeBinary;
}
/**
* Returns the tip text for this property
*
* @return tip text for this property suitable for
* displaying in the explorer/experimenter gui
*/
public String useBinNumbersTipText() {
return "Use bin numbers (eg BXofY) rather than ranges for for discretized attributes";
}
/**
* Gets whether bin numbers rather than ranges should be used for discretized attributes.
*
* @return true if bin numbers should be used
*/
public boolean getUseBinNumbers() {
return m_UseBinNumbers;
}
/**
* Sets whether bin numbers rather than ranges should be used for discretized attributes.
*
* @param useBinNumbers if bin numbers should be used
*/
public void setUseBinNumbers(boolean useBinNumbers) {
m_UseBinNumbers = useBinNumbers;
}
/**
* Returns the tip text for this property
*
* @return tip text for this property suitable for
* displaying in the explorer/experimenter gui
*/
public String useKononenkoTipText() {
return "Use Kononenko's MDL criterion. If set to false"
+ " uses the Fayyad & Irani criterion.";
}
/**
* Gets whether Kononenko's MDL criterion is to be used.
*
* @return true if Kononenko's criterion will be used.
*/
public boolean getUseKononenko() {
return m_UseKononenko;
}
/**
* Sets whether Kononenko's MDL criterion is to be used.
*
* @param useKon true if Kononenko's one is to be used
*/
public void setUseKononenko(boolean useKon) {
m_UseKononenko = useKon;
}
/**
* Returns the tip text for this property
*
* @return tip text for this property suitable for
* displaying in the explorer/experimenter gui
*/
public String useBetterEncodingTipText() {
return "Uses a more efficient split point encoding.";
}
/**
* Gets whether better encoding is to be used for MDL.
*
* @return true if the better MDL encoding will be used
*/
public boolean getUseBetterEncoding() {
return m_UseBetterEncoding;
}
/**
* Sets whether better encoding is to be used for MDL.
*
* @param useBetterEncoding true if better encoding to be used.
*/
public void setUseBetterEncoding(boolean useBetterEncoding) {
m_UseBetterEncoding = useBetterEncoding;
}
/**
* Returns the tip text for this property
*
* @return tip text for this property suitable for
* displaying in the explorer/experimenter gui
*/
public String invertSelectionTipText() {
return "Set attribute selection mode. If false, only selected"
+ " (numeric) attributes in the range will be discretized; if"
+ " true, only non-selected attributes will be discretized.";
}
/**
* Gets whether the supplied columns are to be removed or kept
*
* @return true if the supplied columns will be kept
*/
public boolean getInvertSelection() {
return m_DiscretizeCols.getInvert();
}
/**
* Sets whether selected columns should be removed or kept. If true the
* selected columns are kept and unselected columns are deleted. If false
* selected columns are deleted and unselected columns are kept.
*
* @param invert the new invert setting
*/
public void setInvertSelection(boolean invert) {
m_DiscretizeCols.setInvert(invert);
}
/**
* Returns the tip text for this property
*
* @return tip text for this property suitable for
* displaying in the explorer/experimenter gui
*/
public String attributeIndicesTipText() {
return "Specify range of attributes to act on."
+ " This is a comma separated list of attribute indices, with"
+ " \"first\" and \"last\" valid values. Specify an inclusive"
+ " range with \"-\". E.g: \"first-3,5,6-10,last\".";
}
/**
* Gets the current range selection
*
* @return a string containing a comma separated list of ranges
*/
public String getAttributeIndices() {
return m_DiscretizeCols.getRanges();
}
/**
* Sets which attributes are to be Discretized (only numeric
* attributes among the selection will be Discretized).
*
* @param rangeList a string representing the list of attributes. Since
* the string will typically come from a user, attributes are indexed from
* 1. <br>
* eg: first-3,5,6-last
* @throws IllegalArgumentException if an invalid range list is supplied
*/
public void setAttributeIndices(String rangeList) {
m_DiscretizeCols.setRanges(rangeList);
}
/**
* Sets which attributes are to be Discretized (only numeric
* attributes among the selection will be Discretized).
*
* @param attributes an array containing indexes of attributes to Discretize.
* Since the array will typically come from a program, attributes are indexed
* from 0.
* @throws IllegalArgumentException if an invalid set of ranges
* is supplied
*/
public void setAttributeIndicesArray(int [] attributes) {
setAttributeIndices(Range.indicesToRangeList(attributes));
}
/**
* Gets the cut points for an attribute
*
* @param attributeIndex the index (from 0) of the attribute to get the cut points of
* @return an array containing the cutpoints (or null if the
* attribute requested isn't being Discretized
*/
public double [] getCutPoints(int attributeIndex) {
if (m_CutPoints == null) {
return null;
}
return m_CutPoints[attributeIndex];
}
/**
* Gets the bin ranges string for an attribute
*
* @param attributeIndex the index (from 0) of the attribute to get the bin ranges string of
* @return the bin ranges string (or null if the
* attribute requested has been discretized into only one interval.)
*/
public String getBinRangesString(int attributeIndex) {
if (m_CutPoints == null) {
return null;
}
double[] cutPoints = m_CutPoints[attributeIndex];
if (cutPoints == null) {
return "All";
}
StringBuilder sb = new StringBuilder();
boolean first = true;
for (int j = 0, n = cutPoints.length; j <= n; ++ j) {
if (first) {
first = false;
} else {
sb.append(',');
}
sb.append(binRangeString(cutPoints, j));
}
return sb.toString();
}
/**
* Get a bin range string for a specified bin of some
* attribute's cut points.
*
* @param cutPoints The attribute's cut points; never null.
* @param j The bin number (zero based); never out of range.
*
* @return The bin range string.
*/
private static String binRangeString(double[] cutPoints, int j) {
assert cutPoints != null;
int n = cutPoints.length;
assert 0 <= j && j <= n;
return
j == 0 ? ""
+ "("
+ "-inf"
+ "-"
+ Utils.doubleToString(cutPoints[0], 6)
+ "]"
: j == n ? ""
+ "("
+ Utils.doubleToString(cutPoints[n - 1], 6)
+ "-"
+ "inf"
+ ")"
: ""
+ "("
+ Utils.doubleToString(cutPoints[j - 1], 6)
+ "-"
+ Utils.doubleToString(cutPoints[j], 6)
+ "]";
}
/** Generate the cutpoints for each attribute */
protected void calculateCutPoints() {
Instances copy = null;
m_CutPoints = new double [getInputFormat().numAttributes()] [];
for(int i = getInputFormat().numAttributes() - 1; i >= 0; i--) {
if ((m_DiscretizeCols.isInRange(i)) &&
(getInputFormat().attribute(i).isNumeric())) {
// Use copy to preserve order
if (copy == null) {
copy = new Instances(getInputFormat());
}
calculateCutPointsByMDL(i, copy);
}
}
}
/**
* Set cutpoints for a single attribute using MDL.
*
* @param index the index of the attribute to set cutpoints for
* @param data the data to work with
*/
protected void calculateCutPointsByMDL(int index,
Instances data) {
// Sort instances
data.sort(data.attribute(index));
// Find first instances that's missing
int firstMissing = data.numInstances();
for (int i = 0; i < data.numInstances(); i++) {
if (data.instance(i).isMissing(index)) {
firstMissing = i;
break;
}
}
m_CutPoints[index] = cutPointsForSubset(data, index, 0, firstMissing);
}
/**
* Test using Kononenko's MDL criterion.
*
* @param priorCounts
* @param bestCounts
* @param numInstances
* @param numCutPoints
* @return true if the split is acceptable
*/
private boolean KononenkosMDL(double[] priorCounts,
double[][] bestCounts,
double numInstances,
int numCutPoints) {
double distPrior, instPrior, distAfter = 0, sum, instAfter = 0;
double before, after;
int numClassesTotal;
// Number of classes occuring in the set
numClassesTotal = 0;
for (int i = 0; i < priorCounts.length; i++) {
if (priorCounts[i] > 0) {
numClassesTotal++;
}
}
// Encode distribution prior to split
distPrior = SpecialFunctions.log2Binomial(numInstances
+ numClassesTotal - 1,
numClassesTotal - 1);
// Encode instances prior to split.
instPrior = SpecialFunctions.log2Multinomial(numInstances,
priorCounts);
before = instPrior + distPrior;
// Encode distributions and instances after split.
for (int i = 0; i < bestCounts.length; i++) {
sum = Utils.sum(bestCounts[i]);
distAfter += SpecialFunctions.log2Binomial(sum + numClassesTotal - 1,
numClassesTotal - 1);
instAfter += SpecialFunctions.log2Multinomial(sum,
bestCounts[i]);
}
// Coding cost after split
after = Utils.log2(numCutPoints) + distAfter + instAfter;
// Check if split is to be accepted
return (before > after);
}
/**
* Test using Fayyad and Irani's MDL criterion.
*
* @param priorCounts
* @param bestCounts
* @param numInstances
* @param numCutPoints
* @return true if the splits is acceptable
*/
private boolean FayyadAndIranisMDL(double[] priorCounts,
double[][] bestCounts,
double numInstances,
int numCutPoints) {
double priorEntropy, entropy, gain;
double entropyLeft, entropyRight, delta;
int numClassesTotal, numClassesRight, numClassesLeft;
// Compute entropy before split.
priorEntropy = ContingencyTables.entropy(priorCounts);
// Compute entropy after split.
entropy = ContingencyTables.entropyConditionedOnRows(bestCounts);
// Compute information gain.
gain = priorEntropy - entropy;
// Number of classes occuring in the set
numClassesTotal = 0;
for (int i = 0; i < priorCounts.length; i++) {
if (priorCounts[i] > 0) {
numClassesTotal++;
}
}
// Number of classes occuring in the left subset
numClassesLeft = 0;
for (int i = 0; i < bestCounts[0].length; i++) {
if (bestCounts[0][i] > 0) {
numClassesLeft++;
}
}
// Number of classes occuring in the right subset
numClassesRight = 0;
for (int i = 0; i < bestCounts[1].length; i++) {
if (bestCounts[1][i] > 0) {
numClassesRight++;
}
}
// Entropy of the left and the right subsets
entropyLeft = ContingencyTables.entropy(bestCounts[0]);
entropyRight = ContingencyTables.entropy(bestCounts[1]);
// Compute terms for MDL formula
delta = Utils.log2(Math.pow(3, numClassesTotal) - 2) -
(((double) numClassesTotal * priorEntropy) -
(numClassesRight * entropyRight) -
(numClassesLeft * entropyLeft));
// Check if split is to be accepted
return (gain > (Utils.log2(numCutPoints) + delta) / (double)numInstances);
}
/**
* Selects cutpoints for sorted subset.
*
* @param instances
* @param attIndex
* @param first
* @param lastPlusOne
* @return
*/
private double[] cutPointsForSubset(Instances instances, int attIndex,
int first, int lastPlusOne) {
double[][] counts, bestCounts;
double[] priorCounts, left, right, cutPoints;
double currentCutPoint = -Double.MAX_VALUE, bestCutPoint = -1,
currentEntropy, bestEntropy, priorEntropy, gain;
int bestIndex = -1, numCutPoints = 0;
double numInstances = 0;
// Compute number of instances in set
if ((lastPlusOne - first) < 2) {
return null;
}
// Compute class counts.
counts = new double[2][instances.numClasses()];
for (int i = first; i < lastPlusOne; i++) {
numInstances += instances.instance(i).weight();
counts[1][(int)instances.instance(i).classValue()] +=
instances.instance(i).weight();
}
// Save prior counts
priorCounts = new double[instances.numClasses()];
System.arraycopy(counts[1], 0, priorCounts, 0,
instances.numClasses());
// Entropy of the full set
priorEntropy = ContingencyTables.entropy(priorCounts);
bestEntropy = priorEntropy;
// Find best entropy.
bestCounts = new double[2][instances.numClasses()];
for (int i = first; i < (lastPlusOne - 1); i++) {
counts[0][(int)instances.instance(i).classValue()] +=
instances.instance(i).weight();
counts[1][(int)instances.instance(i).classValue()] -=
instances.instance(i).weight();
if (instances.instance(i).value(attIndex) <
instances.instance(i + 1).value(attIndex)) {
currentCutPoint = (instances.instance(i).value(attIndex) +
instances.instance(i + 1).value(attIndex)) / 2.0;
currentEntropy = ContingencyTables.entropyConditionedOnRows(counts);
if (currentEntropy < bestEntropy) {
bestCutPoint = currentCutPoint;
bestEntropy = currentEntropy;
bestIndex = i;
System.arraycopy(counts[0], 0,
bestCounts[0], 0, instances.numClasses());
System.arraycopy(counts[1], 0,
bestCounts[1], 0, instances.numClasses());
}
numCutPoints++;
}
}
// Use worse encoding?
if (!m_UseBetterEncoding) {
numCutPoints = (lastPlusOne - first) - 1;
}
// Checks if gain is zero
gain = priorEntropy - bestEntropy;
if (gain <= 0) {
return null;
}
// Check if split is to be accepted
if ((m_UseKononenko && KononenkosMDL(priorCounts, bestCounts,
numInstances, numCutPoints)) ||
(!m_UseKononenko && FayyadAndIranisMDL(priorCounts, bestCounts,
numInstances, numCutPoints))) {
// Select split points for the left and right subsets
left = cutPointsForSubset(instances, attIndex, first, bestIndex + 1);
right = cutPointsForSubset(instances, attIndex,
bestIndex + 1, lastPlusOne);
// Merge cutpoints and return them
if ((left == null) && (right) == null) {
cutPoints = new double[1];
cutPoints[0] = bestCutPoint;
} else if (right == null) {
cutPoints = new double[left.length + 1];
System.arraycopy(left, 0, cutPoints, 0, left.length);
cutPoints[left.length] = bestCutPoint;
} else if (left == null) {
cutPoints = new double[1 + right.length];
cutPoints[0] = bestCutPoint;
System.arraycopy(right, 0, cutPoints, 1, right.length);
} else {
cutPoints = new double[left.length + right.length + 1];
System.arraycopy(left, 0, cutPoints, 0, left.length);
cutPoints[left.length] = bestCutPoint;
System.arraycopy(right, 0, cutPoints, left.length + 1, right.length);
}
return cutPoints;
} else
return null;
}
/**
* Set the output format. Takes the currently defined cutpoints and
* m_InputFormat and calls setOutputFormat(Instances) appropriately.
*/
protected void setOutputFormat() {
if (m_CutPoints == null) {
setOutputFormat(null);
return;
}
FastVector attributes = new FastVector(getInputFormat().numAttributes());
int classIndex = getInputFormat().classIndex();
for (int i = 0, m = getInputFormat().numAttributes(); i < m; ++ i) {
if ((m_DiscretizeCols.isInRange(i))
&& (getInputFormat().attribute(i).isNumeric())) {
double[] cutPoints = m_CutPoints[i];
if (!m_MakeBinary) {
FastVector attribValues;
if (cutPoints == null) {
attribValues = new FastVector(1);
attribValues.addElement("'All'");
} else {
attribValues = new FastVector(cutPoints.length + 1);
if (m_UseBinNumbers) {
for (int j = 0, n = cutPoints.length; j <= n; ++ j) {
attribValues.addElement("'B" + (j + 1) + "of" + (n + 1) + "'");
}
} else {
for (int j = 0, n = cutPoints.length; j <= n; ++ j) {
attribValues.addElement("'" + binRangeString(cutPoints, j) + "'");
}
}
}
Attribute newAtt = new Attribute(getInputFormat().
attribute(i).name(),
attribValues);
newAtt.setWeight(getInputFormat().attribute(i).weight());
attributes.addElement(newAtt);
} else {
if (cutPoints == null) {
FastVector attribValues = new FastVector(1);
attribValues.addElement("'All'");
Attribute newAtt = new Attribute(getInputFormat().
attribute(i).name(),
attribValues);
newAtt.setWeight(getInputFormat().attribute(i).weight());
attributes.addElement(newAtt);
} else {
if (i < getInputFormat().classIndex()) {
classIndex += cutPoints.length - 1;
}
for (int j = 0, n = cutPoints.length; j < n; ++ j) {
FastVector attribValues = new FastVector(2);
if (m_UseBinNumbers) {
attribValues.addElement("'B1of2'");
attribValues.addElement("'B2of2'");
} else {
double[] binaryCutPoint = {cutPoints[j]};
attribValues.addElement("'" + binRangeString(binaryCutPoint, 0) + "'");
attribValues.addElement("'" + binRangeString(binaryCutPoint, 1) + "'");
}
Attribute newAtt = new Attribute(getInputFormat().
attribute(i).name() + "_" + (j+1),
attribValues);
newAtt.setWeight(getInputFormat().attribute(i).weight());
attributes.addElement(newAtt);
}
}
}
} else {
attributes.addElement(getInputFormat().attribute(i).copy());
}
}
Instances outputFormat =
new Instances(getInputFormat().relationName(), attributes, 0);
outputFormat.setClassIndex(classIndex);
setOutputFormat(outputFormat);
}
/**
* Convert a single instance over. The converted instance is added to
* the end of the output queue.
*
* @param instance the instance to convert
*/
protected void convertInstance(Instance instance) {
int index = 0;
double [] vals = new double [outputFormatPeek().numAttributes()];
// Copy and convert the values
for(int i = 0; i < getInputFormat().numAttributes(); i++) {
if (m_DiscretizeCols.isInRange(i) &&
getInputFormat().attribute(i).isNumeric()) {
int j;
double currentVal = instance.value(i);
if (m_CutPoints[i] == null) {
if (instance.isMissing(i)) {
vals[index] = Utils.missingValue();
} else {
vals[index] = 0;
}
index++;
} else {
if (!m_MakeBinary) {
if (instance.isMissing(i)) {
vals[index] = Utils.missingValue();
} else {
for (j = 0; j < m_CutPoints[i].length; j++) {
if (currentVal <= m_CutPoints[i][j]) {
break;
}
}
vals[index] = j;
}
index++;
} else {
for (j = 0; j < m_CutPoints[i].length; j++) {
if (instance.isMissing(i)) {
vals[index] = Utils.missingValue();
} else if (currentVal <= m_CutPoints[i][j]) {
vals[index] = 0;
} else {
vals[index] = 1;
}
index++;
}
}
}
} else {
vals[index] = instance.value(i);
index++;
}
}
Instance inst = null;
if (instance instanceof SparseInstance) {
inst = new SparseInstance(instance.weight(), vals);
} else {
inst = new DenseInstance(instance.weight(), vals);
}
inst.setDataset(getOutputFormat());
copyValues(inst, false, instance.dataset(), getOutputFormat());
inst.setDataset(getOutputFormat());
push(inst);
}
/**
* Returns the revision string.
*
* @return the revision
*/
public String getRevision() {
return RevisionUtils.extract("$Revision: 9088 $");
}
/**
* Main method for testing this class.
*
* @param argv should contain arguments to the filter: use -h for help
*/
public static void main(String [] argv) {
runFilter(new Discretize(), argv);
}
}