[R] problems with outer (remainder of reply...)

[Bill Venables]

[2nd go.  My previous message was suddenly dispatched before I had
finished.  Sorry about that - MicroSoft again, Sheesh!]

At 10:57 PM 5/6/00 -0400, Faheem Mitha wrote:

>
>Cam some kind person in any case confirm that this is what was meant?
>
>f.vect <- function(x,y) sapply(seq(along=x),function(i)f(x[i],y[i]))
>
>seems to be to only work correctly if x and y are the same length.

Yes it will handle it, but it may not speed things up very much.

You can think of outer as first doing a special kind of recycling, (the
same kind as is done in exapnd.grid in fact), calling the function you
supply once with expanded vector arguments with equal length and
re-arranging the result back into a matrix of the same form.

How do I know this?  I looked at the code for outer()!  It's only a couple
of lines long.

Bill Venables.

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