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/*
* [The "BSD licence"]
* Copyright (c) 2005-2008 Terence Parr
* All rights reserved.
*
* Conversion to C#:
* Copyright (c) 2008-2009 Sam Harwell, Pixel Mine, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
namespace Antlr.Runtime.Misc {
using System.Collections.Generic;
using Antlr.Runtime.JavaExtensions;
using Math = System.Math;
/** <summary>Stats routines needed by profiler etc...</summary>
*
* <remarks>
* note that these routines return 0.0 if no values exist in the X[]
* which is not "correct", but it is useful so I don't generate NaN
* in my output
* </remarks>
*/
public class Stats {
public const string ANTLRWORKS_DIR = "antlrworks";
/** <summary>Compute the sample (unbiased estimator) standard deviation following:</summary>
*
* <remarks>
* Computing Deviations: Standard Accuracy
* Tony F. Chan and John Gregg Lewis
* Stanford University
* Communications of ACM September 1979 of Volume 22 the ACM Number 9
*
* The "two-pass" method from the paper; supposed to have better
* numerical properties than the textbook summation/sqrt. To me
* this looks like the textbook method, but I ain't no numerical
* methods guy.
* </remarks>
*/
public static double Stddev(int[] X) {
int m = X.Length;
if (m <= 1) {
return 0;
}
double xbar = EnumerableExtensions.Average(X);
double s2 = 0.0;
for (int i = 0; i < m; i++) {
s2 += (X[i] - xbar) * (X[i] - xbar);
}
s2 = s2 / (m - 1);
return Math.Sqrt(s2);
}
public static double Stddev(List<int> X) {
int m = X.Count;
if (m <= 1) {
return 0;
}
double xbar = EnumerableExtensions.Average(X);
double s2 = 0.0;
for (int i = 0; i < m; i++) {
s2 += (X[i] - xbar) * (X[i] - xbar);
}
s2 = s2 / (m - 1);
return Math.Sqrt(s2);
}
#if DEBUG
/** <summary>Compute the sample mean</summary> */
[System.Obsolete]
public static double avg(int[] X) {
return EnumerableExtensions.Average(EnumerableExtensions.DefaultIfEmpty(X, 0));
}
[System.Obsolete]
public static int min(int[] X) {
return EnumerableExtensions.Min(EnumerableExtensions.DefaultIfEmpty(X, int.MaxValue));
}
[System.Obsolete]
public static int max(int[] X) {
return EnumerableExtensions.Max(EnumerableExtensions.DefaultIfEmpty(X, int.MinValue));
}
[System.Obsolete]
public static int sum(int[] X) {
return EnumerableExtensions.Sum(X);
}
#endif
public static void WriteReport(string filename, string data) {
string absoluteFilename = GetAbsoluteFileName(filename);
System.IO.Directory.CreateDirectory(System.IO.Path.GetDirectoryName(absoluteFilename));
System.IO.File.AppendAllText(absoluteFilename, data);
}
public static string GetAbsoluteFileName(string filename) {
string personalFolder = System.Environment.GetFolderPath(System.Environment.SpecialFolder.Personal);
return personalFolder + System.IO.Path.DirectorySeparatorChar +
ANTLRWORKS_DIR + System.IO.Path.DirectorySeparatorChar +
filename;
}
}
}