/*
* 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. */
/*
* ChisqMixture.java
* Copyright (C) 2002 University of Waikato, Hamilton, New Zealand
*
*/
package weka.classifiers.functions.pace;
import weka.core.RevisionHandler;
import weka.core.RevisionUtils;
import weka.core.matrix.DoubleVector;
import weka.core.matrix.FlexibleDecimalFormat;
import weka.core.matrix.IntVector;
/** Class for handling discrete functions. <p>
*
* A discrete function here is one that takes non-zero values over a finite
* set of points. <p>
*
* @author Yong Wang (yongwang@cs.waikato.ac.nz)
* @version $Revision: 1.4 $ */
public class DiscreteFunction
implements RevisionHandler {
protected DoubleVector points;
protected DoubleVector values;
/** Constructs an empty discrete function */
public DiscreteFunction()
{
this(null, null);
}
/** Constructs a discrete function with the point values provides and the
* function values are all 1/n.
* @param p the point values
*/
public DiscreteFunction( DoubleVector p )
{
this( p, null );
}
/** Constructs a discrete function with both the point values and
* function values provided.
* @param p the point values
* @param v the function values */
public DiscreteFunction( DoubleVector p, DoubleVector v )
{
points = p;
values = v;
formalize();
}
private DiscreteFunction formalize()
{
if( points == null ) points = new DoubleVector();
if( values == null ) values = new DoubleVector();
if( points.isEmpty() ) {
if( ! values.isEmpty() )
throw new IllegalArgumentException("sizes not match");
}
else {
int n = points.size();
if( values.isEmpty() ) {
values = new DoubleVector( n, 1./n );
}
else {
if( values.size() != n )
throw new IllegalArgumentException("sizes not match");
}
}
return this;
}
/**
* Normalizes the function values with L1-norm.
*/
public DiscreteFunction normalize()
{
if ( ! values.isEmpty() ) {
double s = values.sum();
if( s != 0.0 && s != 1.0 ) values.timesEquals( 1. / s );
}
return this;
}
/**
* Sorts the point values of the discrete function.
*/
public void sort()
{
IntVector index = points.sortWithIndex();
values = values.subvector( index );
}
/**
* Clones the discrete function
*/
public Object clone()
{
DiscreteFunction d = new DiscreteFunction();
d.points = (DoubleVector) points.clone();
d.values = (DoubleVector) values.clone();
return d;
}
/**
* Makes each individual point value unique
*/
public DiscreteFunction unique()
{
int count = 0;
if( size() < 2 ) return this;
for(int i = 1; i <= size() - 1; i++ ) {
if( points.get( count ) != points.get( i ) ) {
count++;
points.set( count, points.get( i ) );
values.set( count, values.get( i ) );
}
else {
values.set( count, values.get(count) + values.get(i) );
}
}
points = (DoubleVector) points.subvector(0, count);
values = (DoubleVector) values.subvector(0, count);
return this;
}
/**
* Returns the size of the point set.
*/
public int size()
{
if( points == null ) return 0;
return points.size();
}
/**
* Gets a particular point value
* @param i the index
*/
public double getPointValue( int i )
{
return points.get(i);
}
/**
* Gets a particular function value
* @param i the index
*/
public double getFunctionValue( int i )
{
return values.get(i);
}
/**
* Sets a particular point value
* @param i the index
*/
public void setPointValue( int i, double p )
{
points.set(i, p);
}
/**
* Sets a particular function value
* @param i the index
*/
public void setFunctionValue( int i, double v )
{
values.set(i, v);
}
/**
* Gets all point values
*/
protected DoubleVector getPointValues()
{
return points;
}
/**
* Gets all function values
*/
protected DoubleVector getFunctionValues()
{
return values;
}
/**
* Returns true if it is empty.
*/
public boolean isEmpty()
{
if( size() == 0 ) return true;
return false;
}
// public void addPoint( double x, double y ) {
// points.addPoint( x );
// values.addPoint( y );
// }
/**
* Returns the combined of two discrete functions
* @param d the second discrete function
* @return the combined discrte function
*/
public DiscreteFunction plus( DiscreteFunction d )
{
return ((DiscreteFunction) clone()).plusEquals( d );
}
/**
* Returns the combined of two discrete functions. The first function is
* replaced with the new one.
* @param d the second discrete function
* @return the combined discrte function */
public DiscreteFunction plusEquals( DiscreteFunction d )
{
points = points.cat( d.points );
values = values.cat( d.values );
return this;
}
/**
* All function values are multiplied by a double
* @param x the multiplier
*/
public DiscreteFunction timesEquals( double x )
{
values.timesEquals( x );
return this;
}
/**
* Converts the discrete function to string.
*/
public String toString()
{
StringBuffer text = new StringBuffer();
FlexibleDecimalFormat nf1 = new FlexibleDecimalFormat( 5 );
nf1.grouping( true );
FlexibleDecimalFormat nf2 = new FlexibleDecimalFormat( 5 );
nf2.grouping( true );
for(int i = 0; i < size(); i++) {
nf1.update( points.get(i) );
nf2.update( values.get(i) );
}
text.append("\t" + nf1.formatString("Points") +
"\t" + nf2.formatString("Values") + "\n\n");
for(int i = 0; i <= size() - 1; i++) {
text.append( "\t" + nf1.format( points.get(i) ) + "\t" +
nf2.format( values.get(i) ) + "\n" );
}
return text.toString();
}
/**
* Returns the revision string.
*
* @return the revision
*/
public String getRevision() {
return RevisionUtils.extract("$Revision: 1.4 $");
}
public static void main( String args[] )
{
double points[] = {2,1,2,3,3};
double values[] = {3,2,4,1,3};
DiscreteFunction d = new DiscreteFunction( new DoubleVector( points ),
new DoubleVector( values ));
System.out.println( d );
d.normalize();
System.out.println( "d (after normalize) = \n" + d );
points[1] = 10;
System.out.println( "d (after setting [1]) = \n" + d);
d.sort();
System.out.println( "d (after sorting) = \n" + d);
d.unique();
System.out.println( "d (after unique) = \n" + d );
}
}