/*
* 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/>.
*/
/*
* Test.java
* Copyright (C) 2000-2012 University of Waikato, Hamilton, New Zealand
*
*/
package weka.datagenerators;
import java.io.Serializable;
import weka.core.Attribute;
import weka.core.Instance;
import weka.core.Instances;
import weka.core.RevisionHandler;
import weka.core.RevisionUtils;
import weka.core.Utils;
/**
* Class to represent a test. <br/>
* <br/>
* The string representation of the test can be supplied in standard notation
* or for a subset of types of attributes in Prolog notation.<br/>
*
* Following examples for all possible tests that can be represented by
* this class, given in standard notation.<br/>
* <br/>
* Examples of tests for numeric attributes:<br/>
* B >= 2.333<br/> B < 4.56<br/>
* <br/>
* Examples of tests for nominal attributes with more then 2 values:<br/>
* A = rain <br/> A != rain<br/>
* <br/>
* Examples of tests for nominal attribute with exactly 2 values:<br/>
* A = false <br/> A = true<br/>
* <br/>
* <br/>
* The Prolog notation is only supplied for numeric attributes and
* for nominal attributes that have the values "true" and "false".<br/>
* <br/>
* Following examples for the Prolog notation provided.<br/>
* <br/>
* Examples of tests for numeric attributes:<br/>
* The same as for standard notation above.<br/>
* <br/>
* Examples of tests for nominal attributes with values "true"and "false":<br/>
* A<br/>
* not(A)<br/>
* <br/>
* (Other nominal attributes are not supported by the Prolog notation.)<br/>
* <br/>
*
* @author Gabi Schmidberger (gabi@cs.waikato.ac.nz)
* @version $Revision: 8034 $
**/
public class Test
implements Serializable, RevisionHandler {
/** for serialization */
static final long serialVersionUID = -8890645875887157782L;
/** the attribute index */
int m_AttIndex;
/** the split */
double m_Split;
/** whether to negate the test */
boolean m_Not;
/** the dataset */
Instances m_Dataset;
/**
* Constructor
*
* @param i the attribute index
* @param s the split
* @param dataset the dataset
*/
public Test(int i, double s, Instances dataset) {
m_AttIndex = i;
m_Split = s;
m_Dataset = dataset;
m_Not = false;
}
/**
* Constructor
*
* @param i the attribute index
* @param s the split
* @param dataset the dataset
* @param n whether to negate the test
*/
public Test(int i, double s, Instances dataset, boolean n) {
m_AttIndex = i;
m_Split = s;
m_Dataset = dataset;
m_Not = n;
}
/**
* Negates the test.
*
* @return the test itself negated
*/
public Test getNot() { // returns a modified copy
return new Test(m_AttIndex, m_Split, m_Dataset, m_Not ? false : true);
}
/**
* Determines whether an instance passes the test.
*
* @param inst the instance
* @return true if the instance satisfies the test, false otherwise
* @throws Exception if something goes wrong
*/
public boolean passesTest(Instance inst) throws Exception {
if (inst.isMissing(m_AttIndex)) return false; // missing values fail
boolean isNominal = inst.attribute(m_AttIndex).isNominal();
double attribVal = inst.value(m_AttIndex);
if (!m_Not) {
if (isNominal) {
if (((int) attribVal) != ((int) m_Split)) return false;
}
else if (attribVal >= m_Split) return false;
} else {
if (isNominal) {
if (((int) attribVal) == ((int) m_Split)) return false;
}
else if (attribVal < m_Split) return false;
}
return true;
}
/**
* Returns the test represented by a string.
*
* @return a string representing the test
*/
public String toString() {
return (m_Dataset.attribute(m_AttIndex).name() + " " +
testComparisonString());
}
/**
* Returns the test represented by a string in Prolog notation.
*
* @return a string representing the test in Prolog notation
*/
public String toPrologString() {
Attribute att = m_Dataset.attribute(m_AttIndex);
StringBuffer str = new StringBuffer();
String attName = m_Dataset.attribute(m_AttIndex).name();
if (att.isNumeric()) {
str = str.append(attName + " ");
if (m_Not) str = str.append(">= " + Utils.doubleToString(m_Split, 3));
else str = str.append("< " + Utils.doubleToString(m_Split, 3));
} else {
String value = att.value((int)m_Split);
if (value == "false") { str = str.append("not(" + attName + ")"); }
else { str = str.append(attName); }
}
return str.toString();
}
/**
* Gives a string representation of the test, starting from the comparison
* symbol.
*
* @return a string representing the test
*/
private String testComparisonString() {
Attribute att = m_Dataset.attribute(m_AttIndex);
if (att.isNumeric()) {
return ((m_Not ? ">= " : "< ") + Utils.doubleToString(m_Split,3));
}
else {
if (att.numValues() != 2)
return ((m_Not ? "!= " : "= ") + att.value((int)m_Split));
else return ("= "
+ (m_Not ?
att.value((int)m_Split == 0 ? 1 : 0) : att.value((int)m_Split)));
}
}
/**
* Gives a string representation of the test in Prolog notation, starting
* from the comparison symbol.
*
* @return a string representing the test in Prolog notation
*/
private String testPrologComparisonString() {
Attribute att = m_Dataset.attribute(m_AttIndex);
if (att.isNumeric()) {
return ((m_Not ? ">= " : "< ") + Utils.doubleToString(m_Split,3));
}
else {
if (att.numValues() != 2)
return ((m_Not ? "!= " : "= ") + att.value((int)m_Split));
else return ("= "
+ (m_Not ? att.value((int)m_Split == 0 ? 1 : 0)
: att.value((int)m_Split)));
}
}
/**
* Compares the test with the test that is given as parameter.
*
* @param t the test the object is compared to
* @return true if the two Tests are equal
*/
public boolean equalTo(Test t) {
return (m_AttIndex == t.m_AttIndex && m_Split == t.m_Split && m_Not == t.m_Not);
}
/**
* Returns the revision string.
*
* @return the revision
*/
public String getRevision() {
return RevisionUtils.extract("$Revision: 8034 $");
}
}