tlumley at u.washington.edu
Thu May 2 18:48:16 CEST 2002
On Thu, 2 May 2002, crambe Christophe wrote:
> I've got a problem with the R function spline.des.
> I use the following arguments:
> When I do spline.des(k,x,ord,derivs)$design on Splus and on R, I don't
> have the same results.
> However, if I take an order ord=4 (ie a spline of degree 3), then, I
> have the same results on Splus and R.
I do get the same results --
Numerical expression has 8 elements: only the first used in: 1:length.out
Condition has 8 elements: only the first used in: if(length.out > 0)
Recall(x, ceiling(length.out/n))[1:length.out] else x
and assuming you meant
I then get the same result from both packages except for the last line of
the matrix, which is all zero in R but is equal to the previous line in
This appears to be a rounding error due to having multiple knots `exactly'
at the maximum value -- if the knot is moved very slightly to the right
then the packages agree again.
Thomas Lumley Asst. Professor, Biostatistics
tlumley at u.washington.edu University of Washington, Seattle
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
More information about the R-help