Re: Building octave 3.8.2 from source on Ubuntu 14.04 for using multiple cores

[lukshuntim]

On Friday, September 05, 2014 03:02 AM, Sunil Shah wrote:
> Hi ST,
>
> Sorry for the incomplete post.

Please use bottom post. It's easier to follow.

> Following up on the link on R you sent:
>
> Using octave 3.8.1 binary package on 14.04 I can switch to atlas and lapack.
>
> /usr/lib/atlas-base/atlas/libblas.so.3
>
> /usr/lib/atlas-base/atlas/liblapack.so.3
>
>
> However, it does not enable octave to use multiple cores for standard
> dense matrix test on lu(randn(5e3))
>
> It is faster than stock blas and atlas.
>
>
> Curiously, unlike the link on R, I can not use
> /usr/lib/openblas-base/libblas.so.3 with
> /usr/lib/atlas-base/atlas/liblapack.so.3
>
>
> I get this error message
>
> /usr/bin/octave-cli: symbol lookup error: /usr/lib/liblapack.so.3:
> undefined symbol: ATL_idamax

You seemed to be mixing the lapack provided by atlas with the blas 
provided by openblas.

Please see the Debian wiki page that I mentioned earlier. It has a 
section on selecting the appropriate lapack package. The link is 
repeated here:

https://wiki.debian.org/DebianScience/LinearAlgebraLibraries

How to run octave faster in the cloud would certainly be interesting to 
people like me who has no such experience.

If your are running octave locally on an x86 machine, I'd suggest you 
remove all atlas related stuff and install openblas. Just read the 
README.Debian that comes with it as suggested in the Debian wiki and 
follow the instructions of re-building openblas locally. Most likely 
your cpu will be detected correctly.

Regards,
ST
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