[Rd] qr.qy and qr.qty give an error message when y is integer and LAPACK=TRUE

Berend Hasselman bhh at xs4all.nl
Mon Dec 3 16:42:13 CET 2012


On 03-12-2012, at 16:17, Martin Maechler wrote:

>>>>>> Berend Hasselman <bhh at xs4all.nl>
>>>>>>    on Mon, 3 Dec 2012 15:25:21 +0100 writes:
> 
>> With this example
> 
>> set.seed(123) A <- matrix(runif(40), nrow = 8) y <-
>> 1:nrow(A)
> 
>> A.laqr <- qr(A, LAPACK=TRUE)
> 
>> both qr.qy(A.laqr,y) and qr.qty(A.laqr,y) give the
>> respective error messages
> 
>> Error in qr.qy(A.laqr, y) : 'b' must be a numeric matrix
>> Error in qr.qty(A.laqr, y) : 'b' must be a numeric matrix
> 
>> However when Lapack is not used as in
> 
>> A.liqr <- qr(A, LAPACK=FALSE)
> 
>> qr.qy(A.liqr,y) and qr.qty(A.liqr,y) don't issue error
>> messages.
> 
> You are right... if you look at R 2.15.2 (or even it's patched
> version).
> 

Which I did. And copied from R 2.15.2.

>> Looking at the source of qr.qy and qr.qty in
>> https://svn.r-project.org/R/trunk/src/library/base/R/qr.R
> 
> Hmm, no: If  you really looked at that code (during the last several weeks),
> you would have noted that the code has *changed* from what you
> give below...
> 

> and the current R development version uses  
> .Internal(.) instead of .Call()  and the C code behind the
> .Internal() nicely deals with integer 'y' as well.
> 

I did look at that code but did not drill down. Stupid.

> In short, this is already fixed in R, since ~ September,
> but it won't probably be fixed in "R 2.15.2 patched" ...
> 

Apologies for the noise.

Berend



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