Java Entropy Calculate entropy(double[] p)

Description

entropy

License

Apache License

Declaration

public static Double entropy(double[] p) 

Method Source Code

//package com.java2s;
/*******************************************************************************
 * Copyright 2012 Panos Ipeirotis/*from w w w .  j a v  a 2s.c om*/
 * 
 * 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.
 ******************************************************************************/

public class Main {
    public static Double entropy(double[] p) {

        double h = 0;
        for (int i = 0; i < p.length; i++) {
            h += (p[i] > 0) ? p[i] * Math.log(p[i]) : 0.0;
        }
        return -h;
    }
}

Related

1. computeEntropy(int pos, int neg)
2. discreteEntropy(int[] sequence, int numStates)
3. discretiseMaxEntropy(double data[], int numBins)
4. entropy(byte[] f)
5. entropy(double[] distribution)
6. entropy(double[] vals)
7. entropy(int hist[])
8. entropy(int numBins, double[] _f)
9. entropy(int total, double[] data)