KDE 4.0 API Reference kcalc
stats.cpp
Go to the documentation of this file.00001 /* 00002 $Id: stats.cpp 493364 2006-01-02 10:30:13Z kniederk $ 00003 00004 KCalc, a scientific calculator for the X window system using the 00005 Qt widget libraries, available at no cost at http://www.troll.no 00006 00007 Copyright (C) 1996 Bernd Johannes Wuebben 00008 wuebben@math.cornell.edu 00009 00010 This program is free software; you can redistribute it and/or modify 00011 it under the terms of the GNU General Public License as published by 00012 the Free Software Foundation; either version 2 of the License, or 00013 (at your option) any later version. 00014 00015 This program is distributed in the hope that it will be useful, 00016 but WITHOUT ANY WARRANTY; without even the implied warranty of 00017 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00018 GNU General Public License for more details. 00019 00020 You should have received a copy of the GNU General Public License 00021 along with this program; if not, write to the Free Software 00022 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. 00023 00024 */ 00025 00026 00027 #include "stats.h" 00028 #ifdef DEBUG_STATS 00029 #include <stdio.h> 00030 #endif 00031 00032 KStats::KStats() { 00033 error_flag = false; 00034 } 00035 00036 KStats::~KStats() { 00037 } 00038 00039 void KStats::clearAll() { 00040 mData.clear(); 00041 } 00042 00043 void KStats::enterData(KNumber const & _data) { 00044 00045 mData.push_back(_data); 00046 #ifdef DEBUG_STATS 00047 printf("Added %Lg\n", _data); 00048 printf("count %d\n", mData.size()); 00049 #endif 00050 00051 } 00052 00053 00054 void KStats::clearLast(void) { 00055 00056 mData.pop_back(); 00057 #ifdef DEBUG_STATS 00058 printf("count %d\n",mData.size()); 00059 #endif 00060 00061 00062 } 00063 00064 KNumber KStats::sum(void) { 00065 00066 KNumber result = 0; 00067 QVector<KNumber>::iterator p; 00068 00069 for(p = mData.begin(); p != mData.end(); ++p) { 00070 result += *p; 00071 } 00072 00073 #ifdef DEBUG_STATS 00074 printf("Sum %Lg\n", result); 00075 #endif 00076 00077 return result; 00078 } 00079 00080 KNumber KStats::median(void) { 00081 00082 KNumber result = 0; 00083 unsigned int bound; 00084 size_t index; 00085 00086 bound = count(); 00087 00088 if (bound == 0){ 00089 error_flag = true; 00090 return 0; 00091 } 00092 00093 if (bound == 1) 00094 return mData.at(0); 00095 00096 // need to copy mData-list, because sorting afterwards 00097 QVector<KNumber> tmp_mData(mData); 00098 qSort(tmp_mData); 00099 00100 if( bound & 1) { // odd 00101 index = (bound - 1 ) / 2 + 1; 00102 result = tmp_mData.at(index - 1); 00103 } else { // even 00104 index = bound / 2; 00105 result = ((tmp_mData.at(index - 1)) + (tmp_mData.at(index))) / KNumber(2); 00106 } 00107 00108 return result; 00109 } 00110 00111 00112 KNumber KStats::std_kernel(void) 00113 { 00114 KNumber result = KNumber::Zero; 00115 KNumber _mean; 00116 QVector<KNumber>::iterator p; 00117 00118 _mean = mean(); 00119 00120 for(p = mData.begin(); p != mData.end(); ++p) { 00121 result += (*p - _mean) * (*p - _mean); 00122 } 00123 00124 return result; 00125 } 00126 00127 00128 KNumber KStats::sum_of_squares() { 00129 00130 KNumber result = 0; 00131 QVector<KNumber>::iterator p; 00132 00133 for(p = mData.begin(); p != mData.end(); ++p) { 00134 result += ((*p) * (*p)); 00135 } 00136 00137 return result; 00138 } 00139 00140 00141 KNumber KStats::mean(void) 00142 { 00143 if(count() == 0){ 00144 error_flag = true; 00145 return 0; 00146 } 00147 00148 return (sum() / KNumber(count())); 00149 } 00150 00151 00152 KNumber KStats::std(void) 00153 { 00154 if(count() == 0){ 00155 error_flag = true; 00156 return KNumber::Zero; 00157 } 00158 00159 return (std_kernel() / KNumber(count())).sqrt(); 00160 } 00161 00162 00163 KNumber KStats::sample_std(void) { 00164 KNumber result = 0; 00165 00166 if(count() < 2 ){ 00167 error_flag = true; 00168 return KNumber::Zero; 00169 } 00170 00171 result = (std_kernel() / KNumber(count() - 1)).sqrt(); 00172 00173 // result = result/(count() - 1); 00174 #ifdef DEBUG_STATS 00175 printf("sample std: %Lg\n",result); 00176 #endif 00177 00178 return result; 00179 } 00180 00181 00182 int KStats::count(void) const 00183 { 00184 return static_cast<int>(mData.size()); 00185 } 00186 00187 00188 bool KStats::error() { 00189 00190 bool value = error_flag; 00191 error_flag = false; 00192 return value; 00193 } 00194 00195 00196
