WeibullRV.cppGo to the documentation of this file.00001 /* ****************************************************************** ** 00002 ** OpenSees - Open System for Earthquake Engineering Simulation ** 00003 ** Pacific Earthquake Engineering Research Center ** 00004 ** ** 00005 ** ** 00006 ** (C) Copyright 2001, The Regents of the University of California ** 00007 ** All Rights Reserved. ** 00008 ** ** 00009 ** Commercial use of this program without express permission of the ** 00010 ** University of California, Berkeley, is strictly prohibited. See ** 00011 ** file 'COPYRIGHT' in main directory for information on usage and ** 00012 ** redistribution, and for a DISCLAIMER OF ALL WARRANTIES. ** 00013 ** ** 00014 ** Developed by: ** 00015 ** Frank McKenna (fmckenna@ce.berkeley.edu) ** 00016 ** Gregory L. Fenves (fenves@ce.berkeley.edu) ** 00017 ** Filip C. Filippou (filippou@ce.berkeley.edu) ** 00018 ** ** 00019 ** Reliability module developed by: ** 00020 ** Terje Haukaas (haukaas@ce.berkeley.edu) ** 00021 ** Armen Der Kiureghian (adk@ce.berkeley.edu) ** 00022 ** ** 00023 ** ****************************************************************** */ 00024 00025 // $Revision: 1.6 $ 00026 // $Date: 2003/03/04 00:44:37 $ 00027 // $Source: /usr/local/cvs/OpenSees/SRC/reliability/domain/distributions/WeibullRV.cpp,v $ 00028 00029 00030 // 00031 // Written by Terje Haukaas (haukaas@ce.berkeley.edu) 00032 // 00033 00034 #include <WeibullRV.h> 00035 #include <math.h> 00036 #include <string.h> 00037 #include <GammaRV.h> 00038 #include <classTags.h> 00039 #include <OPS_Globals.h> 00040 00041 WeibullRV::WeibullRV(int passedTag, 00042 double passedMean, 00043 double passedStdv, 00044 double passedStartValue) 00045 :RandomVariable(passedTag, RANDOM_VARIABLE_weibull) 00046 { 00047 tag = passedTag; 00048 setParameters(passedMean,passedStdv); 00049 startValue = passedStartValue; 00050 } 00051 WeibullRV::WeibullRV(int passedTag, 00052 double passedParameter1, 00053 double passedParameter2, 00054 double passedParameter3, 00055 double passedParameter4, 00056 double passedStartValue) 00057 :RandomVariable(passedTag, RANDOM_VARIABLE_weibull) 00058 { 00059 tag = passedTag ; 00060 u = passedParameter1; 00061 k = passedParameter2; 00062 startValue = passedStartValue; 00063 } 00064 WeibullRV::WeibullRV(int passedTag, 00065 double passedMean, 00066 double passedStdv) 00067 :RandomVariable(passedTag, RANDOM_VARIABLE_weibull) 00068 { 00069 tag = passedTag; 00070 setParameters(passedMean,passedStdv); 00071 startValue = getMean(); 00072 } 00073 WeibullRV::WeibullRV(int passedTag, 00074 double passedParameter1, 00075 double passedParameter2, 00076 double passedParameter3, 00077 double passedParameter4) 00078 :RandomVariable(passedTag, RANDOM_VARIABLE_weibull) 00079 { 00080 tag = passedTag ; 00081 u = passedParameter1; 00082 k = passedParameter2; 00083 startValue = getMean(); 00084 } 00085 00086 00087 WeibullRV::~WeibullRV() 00088 { 00089 } 00090 00091 00092 void 00093 WeibullRV::Print(OPS_Stream &s, int flag) 00094 { 00095 } 00096 00097 00098 double 00099 WeibullRV::getPDFvalue(double rvValue) 00100 { 00101 double result; 00102 if ( 0.0 < rvValue) { 00103 result = k/u * pow(rvValue/u,k-1) * exp(-pow(rvValue/u,k)); 00104 } 00105 else { 00106 result = 0.0; 00107 } 00108 return result; 00109 } 00110 00111 00112 double 00113 WeibullRV::getCDFvalue(double rvValue) 00114 { 00115 double result; 00116 if ( 0.0 < rvValue) { 00117 result = 1 - exp(-pow(rvValue/u,k)); 00118 } 00119 else { 00120 result = 0.0; 00121 } 00122 return result; 00123 } 00124 00125 00126 double 00127 WeibullRV::getInverseCDFvalue(double probValue) 00128 { 00129 return u * pow((-log(1-probValue)),(1/k)); 00130 } 00131 00132 00133 const char * 00134 WeibullRV::getType() 00135 { 00136 return "WEIBULL"; 00137 } 00138 00139 00140 double 00141 WeibullRV::getMean() 00142 { 00143 GammaRV *aGammaRV = new GammaRV(1, 0.0, 1.0, 0.0); 00144 double result = u * aGammaRV->gammaFunction(1.0+1.0/k); 00145 delete aGammaRV; 00146 return result; 00147 } 00148 00149 00150 00151 double 00152 WeibullRV::getStdv() 00153 { 00154 GammaRV *aGammaRV = new GammaRV(1, 0.0, 1.0, 0.0); 00155 double a = aGammaRV->gammaFunction(1.0+2.0/k); 00156 double b = aGammaRV->gammaFunction(1.0+1.0/k); 00157 delete aGammaRV; 00158 double result = u*sqrt(a-b*b); 00159 return result; 00160 } 00161 00162 00163 double 00164 WeibullRV::getStartValue() 00165 { 00166 return startValue; 00167 } 00168 00169 double WeibullRV::getParameter1() {return u;} 00170 double WeibullRV::getParameter2() {return k;} 00171 double WeibullRV::getParameter3() {opserr<<"No such parameter in r.v. #"<<tag<<endln; return 0.0;} 00172 double WeibullRV::getParameter4() {opserr<<"No such parameter in r.v. #"<<tag<<endln; return 0.0;} 00173 00174 void 00175 WeibullRV::setParameters(double mean, double stdv) 00176 { 00177 double cov = stdv/mean; 00178 double xk = 0.0; 00179 function141(xk, cov,mean); 00180 } 00181 00182 00183 void 00184 WeibullRV::function141(double xk, double cov, double mean) 00185 { 00186 GammaRV *aGammaRV = new GammaRV(1, 0.0, 1.0, 0.0); 00187 xk = xk + 1.0; 00188 double x1 = 1.0 + 1.0/xk; 00189 double x2 = 1.0 + 2.0/xk; 00190 double gm1 = aGammaRV->gammaFunction(x1); 00191 double gm2 = aGammaRV->gammaFunction(x2); 00192 delete aGammaRV; 00193 double vy = sqrt(gm2/gm1/gm1 - 1.0); 00194 if (cov-vy < 0.0) 00195 function141(xk,cov,mean); 00196 else if (cov-vy == 0.0) 00197 function144(xk,cov,mean); 00198 else 00199 function142(xk,cov,mean); 00200 } 00201 void 00202 WeibullRV::function142(double xk, double cov, double mean) 00203 { 00204 xk = xk - 0.1; 00205 double x1 = 1.0 + 1.0/xk; 00206 double x2 = 1.0 + 2.0/xk; 00207 GammaRV *aGammaRV = new GammaRV(1, 0.0, 1.0, 0.0); 00208 double gm1 = aGammaRV->gammaFunction(x1); 00209 double gm2 = aGammaRV->gammaFunction(x2); 00210 delete aGammaRV; 00211 double vy = sqrt(gm2/gm1/gm1 - 1.0); 00212 if (cov-vy < 0.0) 00213 function143(xk,cov,mean); 00214 else if (cov-vy == 0.0) 00215 function144(xk,cov,mean); 00216 else 00217 function142(xk,cov,mean); 00218 } 00219 void 00220 WeibullRV::function143(double xk, double cov, double mean) 00221 { 00222 xk = xk + 0.01; 00223 double x1 = 1.0 + 1.0/xk; 00224 double x2 = 1.0 + 2.0/xk; 00225 GammaRV *aGammaRV = new GammaRV(1, 0.0, 1.0, 0.0); 00226 double gm1 = aGammaRV->gammaFunction(x1); 00227 double gm2 = aGammaRV->gammaFunction(x2); 00228 delete aGammaRV; 00229 double vy = sqrt(gm2/gm1/gm1 - 1.0); 00230 if (cov-vy < 0.0) 00231 function143(xk,cov,mean); 00232 else if (cov-vy == 0.0) 00233 function144(xk,cov,mean); 00234 else 00235 function144(xk,cov,mean); 00236 00237 00238 } 00239 void 00240 WeibullRV::function144(double xk, double gm1, double mean) 00241 { 00242 u = mean/gm1; 00243 k = xk; 00244 }
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