spencer.graves at pdf.com
Thu Jan 26 00:05:24 CET 2006
I think I was too terse: Why didn't I get an error message? When I
tried the same thing with "dpois", I got an error message:
> D(expression(dpois(x, prob)), "mean")
Error in D(expression(dpois(x, prob)), "mean") :
Function 'dpois' is not in the derivatives table
With "dnorm", I got "0"!. Whe didn't I get an error message?
Thanks for the reply.
Berton Gunter wrote:
> dnorm() is an internal function, so I don't see how D (or deriv) can do
> anything with it symbolically. Am I missing something?
> -- Bert
>>From: r-help-bounces at stat.math.ethz.ch
>>[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Spencer Graves
>>Sent: Wednesday, January 25, 2006 2:43 PM
>>To: r-help at stat.math.ethz.ch
>>Subject: [R] D(dnorm...)?
>> Can someone help me understand the following:
>> > D(expression(dnorm(x, mean)), "mean")
>> > sessionInfo()
>>R version 2.2.1, 2005-12-20, i386-pc-mingw32
>>attached base packages:
>> "methods" "stats" "graphics" "grDevices" "utils"
>> By my computations, this should be something like
>> Thanks for your help.
>> Spencer Graves
>>R-help at stat.math.ethz.ch mailing list
>>PLEASE do read the posting guide!
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