[Rd] Documentation of colSums et. al (PR#4154)

Douglas Grove dgrove at fhcrc.org
Mon Sep 15 12:05:54 MEST 2003


Thanks for fixing this.  

I was initially confused, but then thought about the two
dimensional case (matrix) and realized the doc. was incorrect.

Doug



On 15 Sep 2003, Peter Dalgaard BSA wrote:

> David Brahm  <brahm at alum.mit.edu> writes:
> 
> > Doug Grove <dgrove at fhcrc.org> wrote:
> > > Minor mistake in the documentation on the colSums page.
> > > In the ARGUMENTS section it states for 'dims' that:
> > >    For `col*', the sum or mean is over dimensions
> > >    `dims+1, ...'; for `row*' it is over dimensions `1:dims'.
> > > These two are reversed.
> > 
> > I think Doug is correct, isn't he?  For example, with a 5-dimensional array and
> > dims=3, colSums() sums over the first 3 dimensions (the "rows") and produces a
> > 2-dimensional result.  So the sum is over dimensions 1:dims.
> > 
> > By the way, S-Plus (6.1.2) documentation is also incorrect; it says "colMeans
> > is a 2 dimensional array consisting of the means across the last 3 dimensions"
> > but it's really across the first 3 dimensions.
> > 
> > So why has this bug report ended up in the "trashcan"?
> 
> Quite possibly, it got engulfed in spam... Thomas did the move along
> with several spam messages, but Brian had already fixed the typo at
> that point. The current text reads
> 
> 
>     dims: Which dimensions are regarded as "rows" or "columns" to sum
>           over.  For 'row*', the sum or mean is over dimensions
>           'dims+1, ...'; for 'col*' it is over dimensions '1:dims'.
> 
> 
> 
> -- 
>    O__  ---- Peter Dalgaard             Blegdamsvej 3  
>   c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
>  (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
> ~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907
>



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