[Rd] Re: [R] too large alpha or beta in dbeta ? (PR#643)

[Duncan Murdoch]

On Fri, 25 Aug 2000 15:20:10 +0200 (MET DST), Martin Maechler wrote in
message <200008251320.PAA05152@pubhealth.ku.dk>:

>Look at
>
>> plot(function(x)    dbeta(x, 534,646, log = TRUE), n = 1001)

I never knew that plot could take a function!  

Could I make some suggestions?

1.  It should be mentioned more prominently in the documentation.
Since functions aren't a class, I scanned over the list of plot
methods without ever noticing that functions were mentioned there.
I'd suggest modifying the description of parameter x to read:

 x: the coordinates of points in the plot. Alternatively, a
single plotting structure, function or R object with a `plot' method
can be provided.


2.  If xlim is specified and from and to aren't, the from and to
values should default to xlim[1] and xlim[2], not 0 and 1.  

3.  The help for plot.function says:

"This used to be a quick hack which seems to serve a useful
purpose, but can give bad results for functions which are not
smooth."

That doesn't read right:  it makes me ask, "If it used to be a quick
hack, what is it now?"  I'd suggest:

"This function was a quick hack which seems to serve a useful
purpose, but it can give bad results for functions which are not
smooth."


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