smile.math.distance.ChebyshevDistance Maven / Gradle / Ivy
/*******************************************************************************
* Copyright (c) 2010 Haifeng Li
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*******************************************************************************/
package smile.math.distance;
/**
* Chebyshev distance (or Tchebychev distance), or L∞ metric
* is a metric defined on a vector space where the distance between two vectors
* is the greatest of their differences along any coordinate dimension.
*
* @author Haifeng Li
*/
public class ChebyshevDistance implements Metric {
/**
* Constructor.
*/
public ChebyshevDistance() {
}
@Override
public String toString() {
return "Chebyshev distance";
}
/**
* Chebyshev distance between the two arrays of type integer.
*/
public static double d(int[] x, int[] y) {
if (x.length != y.length)
throw new IllegalArgumentException(String.format("Arrays have different length: x[%d], y[%d]", x.length, y.length));
double dist = 0.0;
for (int i = 0; i < x.length; i++) {
double d = Math.abs(x[i] - y[i]);
if (dist < d)
dist = d;
}
return dist;
}
/**
* Chebyshev distance between the two arrays of type float.
* NaN will be treated as missing values and will be excluded from the
* calculation.
*/
public static double d(float[] x, float[] y) {
if (x.length != y.length)
throw new IllegalArgumentException(String.format("Arrays have different length: x[%d], y[%d]", x.length, y.length));
double dist = 0.0;
for (int i = 0; i < x.length; i++) {
if (!Float.isNaN(x[i]) && !Float.isNaN(y[i])) {
double d = Math.abs(x[i] - y[i]);
if (dist < d)
dist = d;
}
}
return dist;
}
/**
* Chebyshev distance between the two arrays of type double.
* NaN will be treated as missing values and will be excluded from the
* calculation.
*/
@Override
public double d(double[] x, double[] y) {
if (x.length != y.length)
throw new IllegalArgumentException(String.format("Arrays have different length: x[%d], y[%d]", x.length, y.length));
double dist = 0.0;
for (int i = 0; i < x.length; i++) {
if (!Double.isNaN(x[i]) && !Double.isNaN(y[i])) {
double d = Math.abs(x[i] - y[i]);
if (dist < d)
dist = d;
}
}
return dist;
}
}