[Numpy-discussion] Build questions, atlas, lapack... (original) (raw)

Fernando Perez fperez.net at gmail.com
Thu Jun 8 22:25:59 EDT 2006

On 6/8/06, Simon Burton <simon at arrowtheory.com> wrote:

On Thu, 8 Jun 2006 16:48:27 -0600 "Fernando Perez" <fperez.net at gmail.com> wrote:

> > In summary, I don't really know if this is actually finding what it > wants or not, given the two messages. I just went through this on debian sarge which is similar. I put this in site.cgf: [atlas] librarydirs = /usr/lib/atlas/ atlaslibs = lapack, blas Then I needed to set LDLIBRARYPATH to point to /usr/lib/atlas/sse2.

[...]

But to really test this is working I ran python under gdb and set a break point on cblasdgemm. Then a call to numpy.dot should break inside the sse2/liblapack.so.3.0.

(also it's a lot faster with the sse2 dgemm) $ env LDLIBRARYPATH=/usr/lib/atlas/sse2 gdb python2.4

OK, thanks a LOT for that gdb trick: it provides a very nice way to understand what's actually going on. self.note("really, learn better use of gdb")

Using that, though, it would then seem as if the build DID successfully find everything without any further action on my part:

longs[dist]> gdb python GNU gdb 6.4-debian ...

(gdb) break cblas_dgemm Function "cblas_dgemm" not defined. Make breakpoint pending on future shared library load? (y or [n]) y

Breakpoint 1 (cblas_dgemm) pending. (gdb) run Starting program: /usr/bin/python

...

Python 2.4.3 (#2, Apr 27 2006, 14:43:58) [GCC 4.0.3 (Ubuntu 4.0.3-1ubuntu5)] on linux2 Type "help", "copyright", "credits" or "license" for more information. (no debugging symbols found)

import numpy Breakpoint 2 at 0x40429860 Pending breakpoint "cblas_dgemm" resolved a=numpy.empty((1024,1024),'d') b=numpy.empty((1024,1024),'d') numpy.dot(a,b) [Switching to Thread 1075428416 (LWP 3919)]

Breakpoint 2, 0x40429860 in cblas_dgemm () from /usr/lib/sse2/libcblas.so.3

Note that on my system, LD_LIBRARY_PATH does NOT contain that dir:

longs[dist]> env | grep LD_LIB LD_LIBRARY_PATH=/usr/local/lf9560/lib:/usr/local/intel/mkl/8.0.2/lib/32:/usr/local/intel/compiler90/lib:/home/fperez/usr/lib:/home/fperez/usr/local/lib:

and I built everything with a plain

setup.py install --prefix=~/tmp/local

without /any/ tweaks to site.cfg, no LD_LIBRARY_PATH modifications or anything else. I just installed atlas-sse2* and lapack3*, but NOT refblas3*.

Basically it seems that the build process does the right thing out of the box, and the warning is spurious. Since I was being extra-careful in this build, I didn't want to let any warning of that kind go unchecked.

It might still be worth fixing that warning to prevent others from going on a similar wild goose chase, but I'm not comfortable touching that code (I don't know if anyone besides Pearu is).

Thanks for the help!

Cheers,

f

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