//******************************************************************************************************//  NumericalAnalysisExtensions.cs - Gbtc////  Copyright © 2012, Grid Protection Alliance.  All Rights Reserved.////  Licensed to the Grid Protection Alliance (GPA) under one or more contributor license agreements. See//  the NOTICE file distributed with this work for additional information regarding copyright ownership.//  The GPA licenses this file to you under the MIT License (MIT), 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.opensource.org/licenses/MIT////  Unless agreed to in writing, the subject software distributed under the License is distributed on an//  "AS-IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. Refer to the//  License for the specific language governing permissions and limitations.////  Code Modification History://  ----------------------------------------------------------------------------------------------------//  09/18/2008 - J. Ritchie Carroll//       Generated original version of source code.//  09/14/2009 - Stephen C. Wills//       Added new header and license agreement.//  12/14/2012 - Starlynn Danyelle Gilliam//       Modified Header.////****************************************************************************************************** using System;using System.Collections.Generic;using System.Linq; namespace GSF.NumericalAnalysis{    /// <summary>Defines extension functions related to numerical analysis over a sequence of data.</summary>    public static class NumericalAnalysisExtensions    {        /// <summary>Computes the standard deviation over a sequence of double values.</summary>        /// <param name="source">Source data sample.</param>        /// <returns>The standard deviation of the sequence.</returns>        /// <exception cref="ArgumentNullException">source is null</exception>        public static double StandardDeviation(this IEnumerable<double> source)        {            if ((object)source == null)                throw new ArgumentNullException("source", "source is null");             double sampleAverage = source.Average();            double totalVariance = 0.0D;            double dataPointDeviation;            int sampleCount = 0;             foreach (double item in source)            {                dataPointDeviation = item - sampleAverage;                totalVariance += dataPointDeviation * dataPointDeviation;                sampleCount++;            }             if (sampleCount > 0)                return Math.Sqrt(totalVariance / sampleCount);            else                return 0.0D;        }         /// <summary>Computes the standard deviation over a sequence of decimal values.</summary>        /// <param name="source">Source data sample.</param>        /// <returns>The standard deviation of the sequence.</returns>        /// <exception cref="ArgumentNullException">source is null</exception>        public static decimal StandardDeviation(this IEnumerable<decimal> source)        {            if ((object)source == null)                throw new ArgumentNullException("source", "source is null");             decimal sampleAverage = source.Average();            decimal totalVariance = 0;            decimal dataPointDeviation;            int sampleCount = 0;             foreach (decimal item in source)            {                dataPointDeviation = item - sampleAverage;                totalVariance += dataPointDeviation * dataPointDeviation;                sampleCount++;            }             if (sampleCount > 0)                return (decimal)Math.Sqrt((double)(totalVariance / sampleCount));            else                return 0;        }         /// <summary>Computes the standard deviation over a sequence of float values.</summary>        /// <param name="source">Source data sample.</param>        /// <returns>The standard deviation of the sequence.</returns>        /// <exception cref="ArgumentNullException">source is null</exception>        public static float StandardDeviation(this IEnumerable<float> source)        {            if ((object)source == null)                throw new ArgumentNullException("source", "source is null");             float sampleAverage = source.Average();            float totalVariance = 0.0F;            float dataPointDeviation;            int sampleCount = 0;             foreach (float item in source)            {                dataPointDeviation = item - sampleAverage;                totalVariance += dataPointDeviation * dataPointDeviation;                sampleCount++;            }             if (sampleCount > 0)                return (float)Math.Sqrt((double)(totalVariance / sampleCount));            else                return 0.0F;        }    }}