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| Source file | Conditionals | Statements | Methods | TOTAL | |||||||||||||||
| Distance.java | 0% | 0% | 0% | 0% |
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package baseCode.math;
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import cern.colt.list.DoubleArrayList;
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import cern.colt.list.IntArrayList;
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/**
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* Alternative distance and similarity metrics for vectors.
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* <p>
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* Copyright (c) 2004
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* </p>
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* <p>
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* Institution:: Columbia University
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* </p>
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*
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* @author Paul Pavlidis
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* @version $Id: Distance.java,v 1.7 2004/08/14 20:38:35 pavlidis Exp $
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*/
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public class Distance { |
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/**
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* Calculate the Manhattan distance between two vectors.
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*
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* @param x DoubleArrayList
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* @param y DoubleArrayList
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* @return Manhattan distance between x and y
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*/
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public double manhattanDistance( DoubleArrayList x, DoubleArrayList y ) { |
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int j;
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double sum = 0.0;
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int numused = 0;
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if ( x.size() != y.size() ) {
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throw new ArithmeticException(); |
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} |
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int length = x.size();
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for ( j = 0; j < length; j++ ) {
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if ( !Double.isNaN( x.elements()[j] )
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&& !Double.isNaN( y.elements()[j] ) ) {
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sum += Math.abs( x.elements()[j] - y.elements()[j] ); |
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numused++; |
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} |
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} |
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return sum;
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} |
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/**
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* Calculate the Euclidean distance between two vectors.
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*
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* @param x DoubleArrayList
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* @param y DoubleArrayList
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* @return Euclidean distance between x and y
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*/
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public double euclDistance( DoubleArrayList x, DoubleArrayList y ) { |
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int j;
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double sum;
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int numused;
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sum = 0.0; |
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numused = 0; |
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if ( x.size() != y.size() ) {
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throw new ArithmeticException(); |
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} |
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int length = x.size();
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for ( j = 0; j < length; j++ ) {
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if ( !Double.isNaN( x.elements()[j] )
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&& !Double.isNaN( y.elements()[j] ) ) {
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sum += Math.pow( ( x.elements()[j] - y.elements()[j] ), 2 ); |
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numused++; |
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} |
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} |
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if ( sum == 0.0 ) {
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return 0.0;
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} |
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return Math.sqrt( sum );
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} |
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/**
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* Spearman Rank Correlation. This does the rank transformation of the data.
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*
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* @param x DoubleArrayList
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* @param y DoubleArrayList
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* @return Spearman's rank correlation between x and y.
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*/
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public static double spearmanRankCorrelation( DoubleArrayList x, |
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DoubleArrayList y ) {
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double sum = 0.0;
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if ( x.size() != y.size() ) {
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throw new ArithmeticException(); |
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} |
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IntArrayList rx = Rank.rankTransform( x ); |
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IntArrayList ry = Rank.rankTransform( y ); |
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for ( int j = 0; j < x.size(); j++ ) { |
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sum += ( rx.elements()[j] - ry.elements()[j] |
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* ( rx.elements()[j] - ry.elements()[j] ) ); |
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} |
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return 1.0 - 6.0 * sum / ( Math.pow( x.size(), 3 ) - x.size() );
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} |
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/**
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* Highly optimized implementation of the Pearson correlation. The inputs must be standardized - mean zero, variance
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* one, without any missing values.
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*
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* @param xe A standardized vector
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* @param ye A standardized vector
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* @return Pearson correlation coefficient.
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*/
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public static double correlationOfStandardized( double[] xe, double[] ye ) { |
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double sxy = 0.0;
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for ( int i = 0, n = xe.length; i < n; i++ ) { |
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double xj = xe[i];
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double yj = ye[i];
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sxy += xj * yj; |
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} |
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return sxy / xe.length;
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} |
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/**
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* Like correlationofNormedFast, but takes DoubleArrayLists as inputs, handles missing values correctly, and does
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* more error checking. Assumes the data has been converted to z scores already.
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*
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* @param x A standardized vector
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* @param y A standardized vector
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* @return The Pearson correlation between x and y.
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*/
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public static double correlationOfStandardized( DoubleArrayList x, |
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DoubleArrayList y ) {
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if ( x.size() != y.size() ) {
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throw new IllegalArgumentException( "Array lengths must be the same" ); |
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} |
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| 140 | 0 |
double[] xe = x.elements();
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| 141 | 0 |
double[] ye = y.elements();
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| 142 | 0 |
double sxy = 0.0;
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| 143 | 0 |
int length = 0;
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| 144 | 0 |
for ( int i = 0, n = x.size(); i < n; i++ ) { |
| 145 | 0 |
double xj = xe[i];
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| 146 | 0 |
double yj = ye[i];
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| 148 | 0 |
if ( Double.isNaN( xj ) || Double.isNaN( yj ) ) {
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continue;
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} |
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sxy += xj * yj; |
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length++; |
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} |
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if ( length == 0 ) {
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return -2.0; // flag of illegal value. |
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} |
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return sxy / length;
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} |
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} |
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