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Re: Undefined symbols when compiled with umfpack using external BLAS

 

LUK ShunTim wrote:
Hello fellow dolfins,

I compiled dolfin 0.6.4 (successfully) using the umfpack package supplied by
debian/sid which does not come with its own BLAS. When testing pydolfin with
"python -i meshdemo.py", it gives this traceback:

<quote>
Traceback (most recent call last):
  File "meshdemo.py", line 1, in ?
    from dolfin import *
  File "/home/test/dolfin/lib/python2.4/site-packages/dolfin/__init__.py", line
3, in ?
    from dolfin import *
  File "/home/test/dolfin/lib/python2.4/site-packages/dolfin/dolfin.py", line 7,
in ?
    import _dolfin
ImportError: /usr/lib/libumfpack.so.1: undefined symbol: dscal_
</quote>

It appears dscal from BLAS routines which is required by umfpack was some how
not linked/imported. I did have ATLAS installed.

The same problem occurred when compiling the c++ examples but it can be worked
around by adding the required flags "-L/usr/lib/atlas/sse2 -lblas" to link
explicitly against ALTAS.

I beg your pardon if this is not really a dolfin problem (I don't know whether
dolfin should do the import or not) but I would be grateful for your help.


I've seen this problem before. Something has changed in the way the Debian libufsparse packages are built.

With Ubunutu 6.10, the package libumfpack4 works fine, but libufsparse needs -lblas. I don't like this as it means DOLFIN has to test for BLAS, and add options for non-standard BLAS installations (yet another dependency). I might add a test for BLAS in the future.

If you grab the "SuiteSparse" (which includes UMFPACK) and build it yourself, it creates static libraries by default, so you won't have to tell DOLFIN where the BLAS libraries are.

Garth




Regards,
ST
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