Here you can find the source of std(double[] a, int size, double mean)
public final static double std(double[] a, int size, double mean)
//package com.java2s; /* //from w w w. j a v a 2 s .c o m * MHAP package * * This software is distributed "as is", without any warranty, including * any implied warranty of merchantability or fitness for a particular * use. The authors assume no responsibility for, and shall not be liable * for, any special, indirect, or consequential damages, or any damages * whatsoever, arising out of or in connection with the use of this * software. * * Copyright (c) 2014 by Konstantin Berlin and Sergey Koren * University Of Maryland * * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You 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 final static double std(double[] a, int size, double mean) { double x = 0.0; for (int iter = 0; iter < size; iter++) { double val = a[iter] - mean; x += val * val; } return Math.sqrt(x / (double) (size - 1)); } public final static double std(int[] a, int size, double mean) { double x = 0.0; for (int iter = 0; iter < size; iter++) { double val = (double) a[iter] - mean; x += val * val; } return Math.sqrt(x / (double) (size - 1)); } }