Re: [R] Bug with curve?

From: Martin Maechler <maechler_at_stat.math.ethz.ch>
Date: Fri, 1 Feb 2008 15:46:31 +0100

>>>>> "BB" == Ben Bolker <bolker_at_ufl.edu> >>>>> on Fri, 1 Feb 2008 14:03:15 +0000 (UTC) writes:

    BB> Paul Smith <phhs80 <at> gmail.com> writes:
>>
>> Dear All,
>>
>> Take this code:
>>
>> > f <- function(x) exp(-x)*x-0.05
>> > g <- function(x) 0
>> > curve(f,0,5)
>> > curve(g,add=T)
>> Error in xy.coords(x, y) : 'x' and 'y' lengths differ
>> >
>>
>> However, with
>>
>> g <- function(x) x-x
>>
>> no error is generated.
>>
>>

    BB> The first paragraph of "details" in the help page     BB> says:

    BB> . 'x(t)' or 'expr' (with 'x' inside) must return a numeric of the same     BB> length as the argument 't' or 'x'.

yes, thanks Ben.

    BB> So no, technically this is not a bug.

why only "technically"?

Paul wouldn't also be able to integrate(g, .), just the error message would be slightly more helpful :

  Error in integrate(g, 0, 1) :
    evaluation of function gave a result of wrong length

    BB> The R idiom for adding a horizontal line to the plot is     BB> abline(h=...)

    BB> cheers
    BB> Ben Bolker



R-help_at_r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Fri 01 Feb 2008 - 14:49:26 GMT

Archive maintained by Robert King, hosted by the discipline of statistics at the University of Newcastle, Australia.
Archive generated by hypermail 2.2.0, at Fri 01 Feb 2008 - 15:30:11 GMT.

Mailing list information is available at https://stat.ethz.ch/mailman/listinfo/r-help. Please read the posting guide before posting to the list.

list of date sections of archive