[Rd] R Lapack – why a subset?

[Peter Dalgaard]

I'm not too happy with this either, but I believe the reason is that there would be a significant extra maintenance burden consisting of things that is not being used by R itself. In particular, complex math routines are little used and have historically caused a number of issues with correct argument and return-value passing. 

Notice that it is a bit of a can of worms involving matching up C and Fortran compilers, OS versions, routines being and not being present in current LAPACK, which may differ from the system-supplied one, etc.

-pd

> On 26 Mar 2018, at 07:49 , Baptiste Auguie <baptiste.auguie at gmail.com> wrote:
> 
> Hi,
> 
> Why doesn't R include a full Lapack but only a subset?
> 
> My cda package (now archived) relying on RcppArmadillo has broken multiple
> times on CRAN over the past few years following updates in the underlying
> Armadillo library, Every time it follows the same pattern: Armadillo adds a
> function to solve a specialised linear system more efficiently, and the
> corresponding Lapack routine is not included in the R Lapack subset used on
> CRAN, causing breakage. The workaround so far has been an unhappy
> compromise with Armadillo developers, adding a "crippled lapack" flag in
> the RcppArmadillo configure script, that triggers the use of alternative
> (suboptimal) routines and passes CRAN checks. Most RcppArmadillo-dependent
> packages don't see the problem; mine seems to be the only one using complex
> linear algebra. Two years ago a large number of Lapack routines were added*
> to R, and this nicely solved the issue for a while. Unfortunately the same
> problem resurfaced last year, with another missing Lapack routine, and my
> package is now archived (though it works fine with an external Lapack).
> More generally, this workaround is not satisfying for various reasons, and
> so I want to ask: why does R ship only a subset of Lapack in the first
> place?
> 
> Best regards,
> 
> baptiste
> 
> * Relevant commit at
> https://github.com/wch/r-source/commit/98acd96f22eb795a933879c0d3f740e802855473
> 
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> 
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-- 
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
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