/*
* 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) 2008-2012 University of Waikato, Hamilton, New Zealand
*
*/
package weka.core.pmml;
import java.io.Serializable;
import java.util.ArrayList;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import weka.core.Attribute;
import weka.core.Utils;
/**
* Class encapsulating a Discretize Expression.
*
* @author Mark Hall (mhall{[at]}pentaho{[dot]}com)
* @version $Revision 1.0 $
*/
public class Discretize extends Expression {
/**
* Inner class to encapsulate DiscretizeBin elements
*/
protected class DiscretizeBin implements Serializable {
/**
* For serialization
*/
private static final long serialVersionUID = 5810063243316808400L;
/** The intervals for this DiscretizeBin */
private ArrayList<FieldMetaInfo.Interval> m_intervals =
new ArrayList<FieldMetaInfo.Interval>();
/** The bin value for this DiscretizeBin */
private String m_binValue;
/**
* If the optype is continuous or ordinal, we will attempt to parse
* the bin value as a number and store it here.
*/
private double m_numericBinValue = Utils.missingValue();
protected DiscretizeBin(Element bin,
FieldMetaInfo.Optype opType) throws Exception {
NodeList iL = bin.getElementsByTagName("Interval");
for (int i = 0; i < iL.getLength(); i++) {
Node iN = iL.item(i);
if (iN.getNodeType() == Node.ELEMENT_NODE) {
FieldMetaInfo.Interval tempInterval = new FieldMetaInfo.Interval((Element)iN);
m_intervals.add(tempInterval);
}
}
m_binValue = bin.getAttribute("binValue");
if (opType == FieldMetaInfo.Optype.CONTINUOUS ||
opType == FieldMetaInfo.Optype.ORDINAL) {
try {
m_numericBinValue = Double.parseDouble(m_binValue);
} catch (NumberFormatException ex) {
// quietly ignore...
}
}
}
/**
* Get the bin value for this DiscretizeBin
*
* @return the bin value
*/
protected String getBinValue() {
return m_binValue;
}
/**
* Get the value of this bin as a number (parsed from the string value).
*
* @return the value of this bin as a number or Double.NaN if the string
* value of the bin could not be interpreted as a number.
*/
protected double getBinValueNumeric() {
return m_numericBinValue;
}
/**
* Returns true if there is an interval that contains the incoming
* value.
*
* @param value the value to check against
* @return true if there is an interval that containst the supplied value
*/
protected boolean containsValue(double value) {
boolean result = false;
for (FieldMetaInfo.Interval i : m_intervals) {
if (i.containsValue(value)) {
result = true;
break;
}
}
return result;
}
public String toString() {
StringBuffer buff = new StringBuffer();
buff.append("\"" + m_binValue + "\" if value in: ");
boolean first = true;
for (FieldMetaInfo.Interval i : m_intervals) {
if (!first) {
buff.append(", ");
} else {
first = false;
}
buff.append(i.toString());
}
return buff.toString();
}
}
/** The name of the field to be discretized */
protected String m_fieldName;
/** The index of the field */
protected int m_fieldIndex;
/** True if a replacement for missing values has been specified */
protected boolean m_mapMissingDefined = false;
/** The value of the missing value replacement (if defined) */
protected String m_mapMissingTo;
/** True if a default value has been specified */
protected boolean m_defaultValueDefined = false;
/** The default value (if defined) */
protected String m_defaultValue;
/** The bins for this discretization */
protected ArrayList<DiscretizeBin> m_bins = new ArrayList<DiscretizeBin>();
/** The output structure of this discretization */
protected Attribute m_outputDef;
/**
* Constructs a Discretize Expression
*
* @param discretize the Element containing the discretize expression
* @param opType the optype of this Discretize Expression
* @param fieldDefs the structure of the incoming fields
* @throws Exception if the optype is not categorical/ordinal or if there
* is a problem parsing this element
*/
public Discretize(Element discretize, FieldMetaInfo.Optype opType, ArrayList<Attribute> fieldDefs)
throws Exception {
super(opType, fieldDefs);
/* if (m_opType == FieldMetaInfo.Optype.CONTINUOUS) {
throw new Exception("[Discretize] must have a categorical or ordinal optype");
} */
m_fieldName = discretize.getAttribute("field");
m_mapMissingTo = discretize.getAttribute("mapMissingTo");
if (m_mapMissingTo != null && m_mapMissingTo.length() > 0) {
m_mapMissingDefined = true;
}
m_defaultValue = discretize.getAttribute("defaultValue");
if (m_defaultValue != null && m_defaultValue.length() > 0) {
m_defaultValueDefined = true;
}
// get the DiscretizeBin Elements
NodeList dbL = discretize.getElementsByTagName("DiscretizeBin");
for (int i = 0; i < dbL.getLength(); i++) {
Node dbN = dbL.item(i);
if (dbN.getNodeType() == Node.ELEMENT_NODE) {
Element dbE = (Element)dbN;
DiscretizeBin db = new DiscretizeBin(dbE, m_opType);
m_bins.add(db);
}
}
if (fieldDefs != null) {
setUpField();
}
}
/**
* Set the field definitions for this Expression to use
*
* @param fieldDefs the field definitions to use
* @throws Exception if there is a problem setting the field definitions
*/
public void setFieldDefs(ArrayList<Attribute> fieldDefs) throws Exception {
super.setFieldDefs(fieldDefs);
setUpField();
}
private void setUpField() throws Exception {
m_fieldIndex = -1;
if (m_fieldDefs != null) {
m_fieldIndex = getFieldDefIndex(m_fieldName);
if (m_fieldIndex < 0) {
throw new Exception("[Discretize] Can't find field " + m_fieldName
+ " in the supplied field definitions.");
}
Attribute field = m_fieldDefs.get(m_fieldIndex);
if (!field.isNumeric()) {
throw new Exception("[Discretize] reference field " + m_fieldName
+" must be continuous.");
}
}
// set up the output structure
Attribute tempAtt = null;
boolean categorical = false;
if (m_opType == FieldMetaInfo.Optype.CONTINUOUS ||
m_opType == FieldMetaInfo.Optype.ORDINAL) {
// check to see if all bin values could be parsed as numbers
for (DiscretizeBin d : m_bins) {
if (Utils.isMissingValue(d.getBinValueNumeric())) {
categorical = true;
break;
}
}
} else {
categorical = true;
}
tempAtt = (categorical)
? new Attribute("temp", (ArrayList<String>)null)
: new Attribute(m_fieldName + "_discretized(optype=continuous)");
if (categorical) {
for (DiscretizeBin d : m_bins) {
tempAtt.addStringValue(d.getBinValue());
}
// add the default value (just in case it is some other value than one
// of the bins
if (m_defaultValueDefined) {
tempAtt.addStringValue(m_defaultValue);
}
// add the map missing to value (just in case it is some other value than one
// of the bins
if (m_mapMissingDefined) {
tempAtt.addStringValue(m_mapMissingTo);
}
// now make this into a nominal attribute
ArrayList<String> values = new ArrayList<String>();
for (int i = 0; i < tempAtt.numValues(); i++) {
values.add(tempAtt.value(i));
}
m_outputDef = new Attribute(m_fieldName + "_discretized", values);
} else {
m_outputDef = tempAtt;
}
}
/**
* Return the structure of the result of applying this Expression
* as an Attribute.
*
* @return the structure of the result of applying this Expression as an
* Attribute.
*/
protected Attribute getOutputDef() {
if (m_outputDef == null) {
// return a "default" output def. This will get replaced
// by a final one when the final field defs are are set
// for all expressions after all derived fields are collected
return (m_opType == FieldMetaInfo.Optype.CATEGORICAL ||
m_opType == FieldMetaInfo.Optype.ORDINAL)
? new Attribute(m_fieldName + "_discretized", new ArrayList<String>())
: new Attribute(m_fieldName + "_discretized(optype=continuous)");
}
return m_outputDef;
}
/**
* Get the result of evaluating the expression. In the case
* of a continuous optype, a real number is returned; in
* the case of a categorical/ordinal optype, the index of the nominal
* value is returned as a double.
*
* @param incoming the incoming parameter values
* @return the result of evaluating the expression
* @throws Exception if there is a problem computing the result
*/
public double getResult(double[] incoming) throws Exception {
// default of a missing value for the result if none of the following
// logic applies
double result = Utils.missingValue();
double value = incoming[m_fieldIndex];
if (Utils.isMissingValue(value)) {
if (m_mapMissingDefined) {
if (m_outputDef.isNominal()) {
result = m_outputDef.indexOfValue(m_mapMissingTo);
} else {
try {
result = Double.parseDouble(m_mapMissingTo);
} catch (NumberFormatException ex) {
throw new Exception("[Discretize] Optype is continuous but value of mapMissingTo "
+"can not be parsed as a number!");
}
}
}
} else {
// look for a bin that has an interval that contains this value
boolean found = false;
for (DiscretizeBin b : m_bins) {
if (b.containsValue(value)) {
found = true;
if (m_outputDef.isNominal()) {
result = m_outputDef.indexOfValue(b.getBinValue());
} else {
result = b.getBinValueNumeric();
}
break;
}
}
if (!found) {
if (m_defaultValueDefined) {
if (m_outputDef.isNominal()) {
result = m_outputDef.indexOfValue(m_defaultValue);
} else {
try {
result = Double.parseDouble(m_defaultValue);
} catch (NumberFormatException ex) {
throw new Exception("[Discretize] Optype is continuous but value of " +
"default value can not be parsed as a number!");
}
}
}
}
}
return result;
}
/**
* Gets the result of evaluating the expression when the
* optype is categorical or ordinal as the actual String
* value.
*
* @param incoming the incoming parameter values
* @return the result of evaluating the expression
* @throws Exception if the optype is continuous
*/
public String getResultCategorical(double[] incoming) throws Exception {
double index = getResult(incoming);
if (Utils.isMissingValue(index)) {
return "**Missing Value**";
}
return m_outputDef.value((int)index);
}
/* (non-Javadoc)
* @see weka.core.pmml.Expression#toString(java.lang.String)
*/
public String toString(String pad) {
StringBuffer buff = new StringBuffer();
buff.append(pad + "Discretize (" + m_fieldName + "):");
for (DiscretizeBin d : m_bins) {
buff.append("\n" + pad + d.toString());
}
if (m_outputDef.isNumeric()) {
buff.append("\n" + pad + "(bin values interpreted as numbers)");
}
if (m_mapMissingDefined) {
buff.append("\n" + pad + "map missing values to: " + m_mapMissingTo);
}
if (m_defaultValueDefined) {
buff.append("\n" + pad + "default value: " + m_defaultValue);
}
return buff.toString();
}
}