error in dweibull (PR#405)
From: setzer.woodrow@epa.gov Date: Thu, 27 Jan 2000 16:37:08 +0100 (MET)
dweibull(0,1,1) evaluates to 0; it should be 1.
Is that not a matter of opinion? Note the help page says
The Weibull distribution with `shape' parameter a and
`scale' parameter b has density given by
f(x) = (a/b) (x/b)^(a-1) exp(- (x/b)^a)
for x > 0.
Note that dweibull(.Machine$double.eps) evaluates to 1.
dweibull(.01,1,1)
[1] 0.9900498
dweibull(.00001,1,1)
[1] 0.99999
dweibull(.Machine$double.eps,1,1)
[1] 1
dweibull(0,1,1)
[1] 0
I would say the Weibull density was defined to be non-zero on (0, Inf), and S-PLUS agrees with me, as does the help page. I don't see a bug in the results you present which are consistent with the documentation.
Brian D. Ripley, ripley@stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272860 (secr) Oxford OX1 3TG, UK Fax: +44 1865 272595 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-devel-request@stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._