Adk44: Created page with "I had some problems using the atlas modules, which seem to be not applicable to all machines (e.g. 64-bit P4s). I compiled my own lapack routines (available from [http://www...."

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Created page with "I had some problems using the atlas modules, which seem to be not applicable to all machines (e.g. 64-bit P4s). I compiled my own lapack routines (available from [http://www...."

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I had some problems using the atlas modules, which seem to be not applicable to all machines (e.g. 64-bit P4s). I compiled my own lapack routines (available from [http://www.netlib.org]. Their documentation is wrong in certain places, but it's kind of obvious what paths they refer to. As Catherine [http://www-theor.ch.cam.ac.uk/IT/software/atlas.html notes], it's not worth doing much tuning, so I just used the bog-standard f77 configuration. I installed it in ~/src/lib/lapack-3.1.1:

<pre>
jss43@keiko:~/src/lib> wget -O - http://www.netlib.org/lapack/lapack.tgz | tar xvzf - # Download and extract to lapack-3.1.1
jss43@keiko:~/src/lib> cd lapack-3.1.1
jss43@keiko:~/src/lib/lapack-3.1.1> cp make.inc.example make.inc # Use g77 configuration. Other examples exist in the INSTALL directory.
jss43@keiko:~/src/lib/lapack-3.1.1> make # A (cursory) glance at the docs implies this makes everything (including BLAS).
[reams of output]
g77: ../../blas_LINUX.a: No such file or directory # FIBBERS!
jss43@keiko:~/src/lib/lapack-3.1.1> cd BLAS/SRC && make && cd - # Fine, we'll make BLAS ourselves...
jss43@keiko:~/src/lib/lapack-3.1.1> make # ...and finish the job.
</pre>

The last make command takes a while to run, so it's worth having a [http://www.nicecupofteaandasitdown.com/ cup of tea] as you wait.
(You can avoid the error in the middle by editing the Makefile.)

The makefile also runs tests which passed. The libraries are blas_LINUX.a and lapack_LINUX.a, so we can link to them to give them more standard names:
<pre>
jss43@keiko:~/src/lib/lapack-3.1.1> ln -s lapack_LINUX.a liblapack.a
jss43@keiko:~/src/lib/lapack-3.1.1> ln -s blas_LINUX.a libblas.a
</pre>
These can now be used in compilation by using:
<pre> -L ~/src/lib/lapack-3.1.1 -llapack -lblas </pre>
in the link line. This is somewhat platform dependent though, so we can make it even easier to use by using [[enviroment modules]] to reduce the link line to:
-llapack -lblas

ADDENDUM:
Actually, not so straightfoward. I found using zdotc caused a segmentation fault. Some google-fu implied this might be due to how g77 and gfortran [http://developer.apple.com/hardwaredrivers/ve/errata.html return values from routines], and causes problems with 4 routines. Catherine, Greg: did you have this issue?

Anyway, I re-compiled using the INSTALL/make.inc.gfortran as the make.inc. I had to do ''make cleanall'', which is different from ''make clean''. zdotc no longer caused any issues.

[[User:cen1001|Catherine]] 09:49, 7 July 2008 (BST) I haven't encountered that, but we gave up supporting ATLAS other than by providing the precompiled binaries about the time gfortran succeeded g77 and I haven't tried building it since, so I expect I'd get the same thing.

Lapack compilation - Revision history

Adk44: Created page with "I had some problems using the atlas modules, which seem to be not applicable to all machines (e.g. 64-bit P4s). I compiled my own lapack routines (available from [http://www...."