[Rd] Re: convolve() design bug
Martin Maechler
Martin Maechler <maechler@stat.math.ethz.ch>
Fri, 17 Nov 2000 16:35:05 +0100
>>>>> "Bill" == Bill Simpson <wsi@gcal.ac.uk> writes --- on R-help :
...
Bill> Use convolve(). Here is an example:
Bill> #Bracewell The Fourier transform and its applications, chap 3 (p.32 in 2nd
Bill> #edition): {2 2 3 3 4} * {1 1 2} = {2 4 9 10 13 10 8}
Bill> x<-c(2,2,3,3,4)
Bill> h<-c(1,1,2)
Bill> out<-convolve(x,rev(h),type="o") #need to do rev due to fault in R code
Bill> I pointed it out several times to the R-developers that
Bill> convolve() should do convolution by default! However they prefer
Bill> it to do correlation by default (which makes no sense to
Bill> me). Anyway the workaround is to use rev(h).
Dear Bill,
as one of those not too responsive way back, here are some
non-convincing reasons:
At that time, we had density rely on convolve's behavior back then,
and the it was old legacy R code on which others might have relied,
etc, etc
But then, I must admit I had forgotten for a while and later never felt
urged anymore.
Can we have something like a ``survey'' ?
Does anybody heavily rely on convolve()'s current behavior ?
{teaching / packages / ...}
Bill, can you (again, I know, exuse us!) detail your suggested changes,
ideally by sending patches against the current *.R and *.Rd files ?
Thank you.
Martin Maechler <maechler@stat.math.ethz.ch> http://stat.ethz.ch/~maechler/
Seminar fuer Statistik, ETH-Zentrum LEO D10 Leonhardstr. 27
ETH (Federal Inst. Technology) 8092 Zurich SWITZERLAND
phone: x-41-1-632-3408 fax: ...-1228 <><
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