From pd.mes at cbs.dk  Mon Mar 26 16:24:32 2018
From: pd.mes at cbs.dk (Peter Dalgaard)
Date: Mon, 26 Mar 2018 14:24:32 +0000
Subject: [Rd] =?windows-1252?q?R_Lapack_=96_why_a_subset=3F?=
In-Reply-To: <CANLFJPp0nvu1MQPQa6Qw0D+Tqb7Z228FZWZQKDtWf8Vr_snX1A@mail.gmail.com>
References: <CANLFJPp0nvu1MQPQa6Qw0D+Tqb7Z228FZWZQKDtWf8Vr_snX1A@mail.gmail.com>
Message-ID: <EBD08220-AD8A-49E6-90BE-90BEAE053AD6@cbs.dk>

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
> 
> 	[[alternative HTML version deleted]]
> 
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-- 
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Office: A 4.23
Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com



[Rd] =?windows-1252?q?R_Lapack_=96_why_a_subset=3F?=
Peter Dalgaard