Re: R-alpha: Fortran (linpack and eispack are dead!)

Peter Dalgaard BSA (pd@kubism.ku.dk)
Fri, 5 Jul 1996 22:07:12 +0200


Date: Fri, 5 Jul 1996 22:07:12 +0200
Message-Id: <199607052007.WAA14602@bush.kubism.ku.dk>
From: Peter Dalgaard BSA <pd@kubism.ku.dk>
To: Luke Tierney <luke@stat.umn.edu>
In-Reply-To: Luke Tierney's message of Mon, 1 Jul 1996 12:40:45 -0500 (CDT)
Subject: Re: R-alpha: Fortran (linpack and eispack are dead!)
 <9607011740.AA07439@nokomis.stat.umn.edu>

In article <9607011740.AA07439@nokomis.stat.umn.edu> Luke Tierney <luke@stat.umn.edu> writes:


   [...] but I would try to resist the
   temptation to muck with what f2c does. It's hard to resist since the
   quality of the array access code f2c produces is so lousy. Maybe
   commercial converters do better -- I haven't tried. on the other hand,
   I also haven't checked whether it matters, i.e. whether the C compilers
   are good enough to optimize out the apparent inefficiencies f2c
   introduces.

I know exactly what you mean.  However, one reassuring thing is to
remember that f2c actually IS a fortran compiler, that has been hacked
to produce C code instead of equivalent assembler code (VAX code if my
memory is not playing tricks on me again). So at least to some extent,
all we are seeing is why good optimization is more important to
Fortraners than C-ers. 

At any rate, IF one wants to hand-optimize, one should probably just
concentrate on the BLAS routines. Linpack is built to have nearly
every important inner-loop construction coded as BLAS calls.


-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard@biostat.ku.dk)             FAX: (+45) 35327907
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
r-testers mailing list -- To (un)subscribe, send
subscribe	or	unsubscribe
(in the "body", not the subject !)  To: r-testers-request@stat.math.ethz.ch
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-