1 /* 2 * [The "BSD licence"] 3 * Copyright (c) 2005-2008 Terence Parr 4 * All rights reserved. 5 * 6 * Conversion to C#: 7 * Copyright (c) 2008-2009 Sam Harwell, Pixel Mine, Inc. 8 * All rights reserved. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. The name of the author may not be used to endorse or promote products 19 * derived from this software without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 namespace Antlr.Runtime.Misc 34 { 35 using System.Collections.Generic; 36 37 using Directory = System.IO.Directory; 38 using Environment = System.Environment; 39 using File = System.IO.File; 40 using Math = System.Math; 41 using Path = System.IO.Path; 42 43 /** <summary>Stats routines needed by profiler etc...</summary> 44 * 45 * <remarks> 46 * note that these routines return 0.0 if no values exist in the X[] 47 * which is not "correct", but it is useful so I don't generate NaN 48 * in my output 49 * </remarks> 50 */ 51 public class Stats 52 { 53 public const string ANTLRWORKS_DIR = "antlrworks"; 54 55 /** <summary>Compute the sample (unbiased estimator) standard deviation following:</summary> 56 * 57 * <remarks> 58 * Computing Deviations: Standard Accuracy 59 * Tony F. Chan and John Gregg Lewis 60 * Stanford University 61 * Communications of ACM September 1979 of Volume 22 the ACM Number 9 62 * 63 * The "two-pass" method from the paper; supposed to have better 64 * numerical properties than the textbook summation/sqrt. To me 65 * this looks like the textbook method, but I ain't no numerical 66 * methods guy. 67 * </remarks> 68 */ Stddev( int[] X )69 public static double Stddev( int[] X ) 70 { 71 int m = X.Length; 72 if ( m <= 1 ) 73 { 74 return 0; 75 } 76 double xbar = Average(X); 77 double s2 = 0.0; 78 for ( int i = 0; i < m; i++ ) 79 { 80 s2 += ( X[i] - xbar ) * ( X[i] - xbar ); 81 } 82 s2 = s2 / ( m - 1 ); 83 return Math.Sqrt( s2 ); 84 } Stddev( List<int> X )85 public static double Stddev( List<int> X ) 86 { 87 int m = X.Count; 88 if ( m <= 1 ) 89 { 90 return 0; 91 } 92 double xbar = Average(X); 93 double s2 = 0.0; 94 for ( int i = 0; i < m; i++ ) 95 { 96 s2 += ( X[i] - xbar ) * ( X[i] - xbar ); 97 } 98 s2 = s2 / ( m - 1 ); 99 return Math.Sqrt( s2 ); 100 } 101 102 /** <summary>Compute the sample mean</summary> */ Average(ICollection<int> X)103 public static double Average(ICollection<int> X) 104 { 105 if (X.Count == 0) 106 return 0.0; 107 108 double sum = 0.0; 109 foreach (int i in X) 110 sum += i; 111 112 return sum / X.Count; 113 } 114 WriteReport( string filename, string data )115 public static void WriteReport( string filename, string data ) 116 { 117 string absoluteFilename = GetAbsoluteFileName( filename ); 118 119 Directory.CreateDirectory( Path.GetDirectoryName( absoluteFilename ) ); 120 File.AppendAllText( absoluteFilename, data ); 121 } 122 GetAbsoluteFileName( string filename )123 public static string GetAbsoluteFileName( string filename ) 124 { 125 string personalFolder = Environment.GetFolderPath( Environment.SpecialFolder.Personal ); 126 return personalFolder + Path.DirectorySeparatorChar + 127 ANTLRWORKS_DIR + Path.DirectorySeparatorChar + 128 filename; 129 } 130 } 131 } 132