[R] problem with outer and image

[Ben Bolker]

Ben Bolker                                  bolker at zoo.ufl.edu
Zoology Department, University of Florida   http://www.zoo.ufl.edu/bolker

On Tue, 5 Oct 1999, Bill Simpson wrote:

> Thanks very much for any help.

  Somebody'll probably answer this before I do -- but -- 

> time<-seq(1:100)
> f<-function(x,time) 10*cos(2*pi*x*3/length(x)+0)+300
> z<-outer(x,time,f)
> image(x,time,z)
> I get a vertical grating as expected, BUT now I get <1 cycle of cos
> wave. Varying the frequency (3 above) does nothing. I don't understand
> what I am doing wrong.


> f<-function(x,time) 10*cos(2*pi*x*3/length(x)+0)+300
                                      ^^^^^^^^^
                                    here's the problem

  The "x" that's getting passed to "outer" is not what you expect.  If you
replace "length(x)" with 100 here, everything seems to do what you'd want.
   
> 
> Bill
> 
> -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
> r-help 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-help-request at stat.math.ethz.ch
> _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
> 
> 

-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-help 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-help-request at stat.math.ethz.ch
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._