/*
* 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 2 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, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*
* Coordinates.java
* Copyright (C) 2004 Stijn Lievens
*
*/
package weka.classifiers.misc.monotone;
import weka.core.Instance;
import weka.core.RevisionHandler;
import weka.core.RevisionUtils;
import java.io.Serializable;
/**
* This is a simple implementation of the data space. The <code>
* Coordinates </code> holds the internal weka value of an instance,
* but <i> with the class removed </i>. The class is immutable,
* and works best when all attibutes are nominal (ordinal), although
* it will not give an error when working with numeric attributes.
* In the latter case, performance will degrade because of the way
* in which the hashcode is calculated.
*
* <p>
* This implementation is part of the master's thesis: "Studie
* en implementatie van instantie-gebaseerde algoritmen voor gesuperviseerd
* rangschikken", Stijn Lievens, Ghent University, 2004.
* </p>
*
* @author Stijn Lievens (stijn.lievens@ugent.be)
* @version $Revision: 5922 $
*/
public class Coordinates
implements Serializable, RevisionHandler {
/** for serialization */
private static final long serialVersionUID = 2319016195345994738L;
/**
* The internal weka values of the attributes of the instance, minus
* the class attribute.
*/
private int[] m_coord;
/**
* The hashcode of this object. Calculated during construction.
*/
private int m_hashCode;
/**
* Create the <code> Coordinates </code> for the given instance.
*
* @param instance the <code> Instance </code> on which the <code>
* Coordinates </code> will be based
*/
public Coordinates(Instance instance) {
double[] values = instance.toDoubleArray();
int classIndex = instance.classIndex();
if (classIndex == -1) {
m_coord = new int[values.length];
} else {
m_coord = new int[values.length - 1];
}
m_hashCode = 0;
int factor=1;
for (int i = 0,j = 0;i < values.length; i++) {
if (i != classIndex) {
m_coord[j] = (int) values[i];
if (i > 0 && i - 1 != classIndex) {
factor *= instance.attribute(i-1).numValues();
} else if (i - 1 == classIndex && classIndex != -1
&& classIndex != 0) {
factor *= instance.attribute(i - 2).numValues();
}
m_hashCode += (m_coord[j])*factor;
j++;
}
}
}
/**
* Get the value of the attribute with index <code> index, </code>
* ignoring the class attribute. Indices are counted starting from
* 0.
*
* @param index the index of the requested attribute
* @return the value of this attribute, in internal floating point format.
*/
public double getValue(int index) {
return m_coord[index];
}
/**
* Get the values of the coordinates.
*
* @param values array serving as output, and the first
* <code> dimension() </code> values are filled in.
*/
public void getValues(double[] values) {
// XXX this is a rather strange method, maybe it should be changed
// into one that returns (using System.arraycopy) the requested values
for (int i = 0; i < m_coord.length; i++) {
values[i] = m_coord[i];
}
}
/**
* Indicates if the object <code> o </code> equals <code> this. </code>
*
* @param o the reference object with which to compare
* @return <code> true </code> if <code> o </code> equals <code>
* this, </code> <code> false </code> otherwise
*/
public boolean equals(Object o) {
if (! (o instanceof Coordinates) ) {
return false;
}
Coordinates cc = (Coordinates) o;
// if the length or hashCodes differ, the objects are certainly not equal
if (m_coord.length != cc.m_coord.length || m_hashCode != cc.m_hashCode) {
return false;
}
for (int i = 0; i < m_coord.length; i++) {
if (m_coord[i] != cc.m_coord[i]) {
return false;
}
}
return true;
}
/**
* Checks if <code> this </code> is strictly smaller than <code> cc. </code>
* This means that for all indices i it holds that
* <code> this.getValue(i) <= cc.getValue(i) </code> and that there is
* at least one index i such that
* <code> this.getValue(i) ≠ cc.getValue(i) </code>
*
* @param cc the <code> Coordinates </code> that <code> this </code> is
* compared to
* @return <code> true </code> if <code> this </code> is strictly
* smaller than <code> cc, </code> <code> false </code> otherwise
* @throws IllegalArgumentException if the dimensions of both objects differ
*/
public boolean strictlySmaller(Coordinates cc) throws IllegalArgumentException {
if (cc.m_coord.length != m_coord.length) {
throw new IllegalArgumentException
("Coordinates are not from the same space");
}
// Skip all equal values
int i = 0;
while(i < m_coord.length && cc.m_coord[i] == m_coord[i]) {
i++;
}
if (i == m_coord.length) {
return false; // equality !
}
for (; i < m_coord.length; i++) {
if (m_coord[i] > cc.m_coord[i]) {
return false;
}
}
return true;
}
/**
* Checks if <code> this </code> is smaller or equal than <code> cc. </code>
* This means that for all indices i it holds that
* <code> this.getValue(i) <= cc.getValue(i). </code>
*
* @param cc the <code> Coordinates </code> that <code> this </code> is
* compared to
* @return <code> true </code> if <code> this </code> is
* smaller or equal than <code> cc, </code> <code> false </code> otherwise
* @throws IllegalArgumentException if the dimensions of both objects differ
*/
public boolean smallerOrEqual(Coordinates cc) throws IllegalArgumentException {
if (cc.m_coord.length != m_coord.length) {
throw new IllegalArgumentException
("Coordinates are not from the same space");
}
for (int i = 0; i < m_coord.length; i++) {
if (m_coord[i] > cc.m_coord[i]) {
return false;
}
}
return true;
}
/**
* Gets the hash code value for this object.
*
* @return the requested hash code
*/
public int hashCode() {
return m_hashCode;
}
/**
* Gets the dimension of the data space, this is the number of attributes,
* exluding the class attribute.
*
* @return the dimension of the data space this object resides in
*/
public int dimension() {
return m_coord.length;
}
/**
* Get a string representation of this object.
*
* @return the requested string representation
*/
public String toString() {
String s = "(";
for (int i = 0; i < m_coord.length - 1; i++) {
s += m_coord[i] + ",";
}
return s + m_coord[m_coord.length - 1] + ")";
}
/**
* Returns the revision string.
*
* @return the revision
*/
public String getRevision() {
return RevisionUtils.extract("$Revision: 5922 $");
}
}