Re: [Rd] Problems with Lapack's eigen() on 64-bit

From: Roger D. Peng <rpeng_at_jhsph.edu>
Date: Tue 27 Jul 2004 - 23:52:20 EST

On our AMD dual Opteron system running SuSE SLES 8 with

gcc version 3.2.2 (SuSE Linux)

and with R built with `./configure --without-blas' I get

 > eigen(cbind(1, 3:1, 1:3))
$values
[1] 5.000000e+00 1.000000e+00 -4.440892e-16

$vectors

           [,1] [,2] [,3]

[1,] 0.5773503 -0.8451543 -0.9428090
[2,] 0.5773503 -0.1690309  0.2357023
[3,] 0.5773503  0.5070926  0.2357023

-roger

Martin Maechler wrote:
> I'm only now realizing that we have severe problems with R on our
> AMD 'Opteron' and 'Athlon64' clients running Redhat Enterprise
> with all 64-bit libraries (AFAICS).
>

> The Lapack problem happens for R-patched and R-devel both on

> the Opteron and the Athlon64.
>

>
Here are platform details:
>

> o "gcc -v" and "g77 -v" both end with the line

> gcc version 3.2.3 20030502 (Red Hat Linux 3.2.3-34)
>

> o I've used ...../configure --without-blas
>

> 1) Opteron ("deb7", a dual-processor compute server):
>
> - uname -a :

> Linux deb7 2.4.21-9.0.3.ELsmp #1 SMP Tue Apr 20 19:44:29 ED
T 2004 x86_64 x86_64 x86_64 GNU/Linux
>
- /proc/cpuinfo contains (among much more)
> vendor_id : AuthenticAMD

>
cpu family : 15
>
model : 5
> model name : AMD Opteron(tm) Processor 248
>

> 2) Athlon64 (a simple "new generation" client - to become my desktop soon):
>
> - uname -a :

> Linux setup-12 2.4.21-15.0.2.EL #1 Wed Jun 16 22:41:44 EDT

> 2004 x86_64 x86_64 x86_64 GNU/Linux
>
> - /proc/cpuinfo contains

> vendor_id : AuthenticAMD

>
cpu family : 15
> model : 14
> model name : AMD Athlon(tm) 64 Processor 2800+
>
> ----------------
>
> Now the Lapack problem, easily seen from the base eigen()
> example:
>

> > eigen(cbind(1, 3:1, 1:3))
> $values
> [1] 5.7015621 1.0000000 -0.7015621
>
> $vectors

> [,1] [,2] [,3]
> [1,] 0.4877939 -0.7181217 -0.9576161
> [2,] 0.6172751 -0.3893848 0.2036804
> [3,] 0.6172751 0.5767849 0.2036804
>

> which is simply plainly wrong and
> eigen(cbind(1, 3:1, 1:3), EISPACK=TRUE)
> gives the correct eigen values c(5, 1, 0) and corresponding
> eigenvectors.
>
> IIRC, we've already dealt with a Lapack problem, and that
> workaround (built into R-devel's Makefiles) has been to use
> -ffloat-store for the compilation of src/modules/lapack/dlamc.f
>
> ----------
>
> Thank you for hints / suggestions.
>
> Others with 64-bit platforms might also try to see what
>
eigen(cbind(1, 3:1, 1:3))
> gives there.
>
> Martin Maechler
>
> ______________________________________________
> R-devel@stat.math.ethz.ch mailing list

> https://www.stat.math.ethz.ch/mailman/listinfo/r-devel
>



R-devel@stat.math.ethz.ch mailing list >
https://www.stat.math.ethz.ch/mailman/listinfo/r-devel Received on Tue Jul 27 23:57:12 2004

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