[SciPy-user] BLAS and srotgm

Robert Kern robert.kern@gmail....
Tue Sep 11 13:02:50 CDT 2007

Donna wrote:
>> Dear SciPy Users :
>> I just got SciPy installed, finally.  (Many thanks to the user who posted 
>> a while ago that the "-shared" flag was needed to build _fftpack.so).
>> But now, when I try to import the blas module, I get the following error :
>> ----------------------------------------------------------------------------
>> Python 2.5 (r25:51908, Sep 10 2007, 00:42:23)
>> [GCC 3.4.0] on linux2
>> Type "help", "copyright", "credits" or "license" for more information.
>>>>> import scipy.linalg.blas
>> Traceback (most recent call last):
>>    File "<stdin>", line 1, in <module>
>>    File
> "/usr/local/Python-2.5-with_tk/lib/python2.5/site-packages/scipy/linalg/
> __init__.py",
>> line 8, in <module>
>>      from basic import *
>>    File
> "/usr/local/Python-2.5-with_tk/lib/python2.5/site-packages/scipy/linalg/
> basic.py", 
>> line 227, in <module>
>>      import decomp
>>    File
> "/usr/local/Python-2.5-with_tk/lib/python2.5/site-packages/scipy/linalg/
> decomp.py", 
>> line 21, in <module>
>>      from blas import get_blas_funcs
>>    File
> "/usr/local/Python-2.5-with_tk/lib/python2.5/site-packages/scipy/linalg/
> blas.py", 
>> line 14, in <module>
>>      from scipy.linalg import fblas
>> ImportError: 
>> /usr/local/Python-2.5-with_tk/lib/python2.5/site-packages/scipy/linalg/
> fblas.so: 
>> undefined symbol: srotmg_
>> ----------------------------------------------------------------------------
> I think I fixed this problem.  In fact, despite my best efforts to make sure
> the scipy build found the latest libblas file, it had in fact found an old one. 
> Maybe the "-lblas" was in the wrong place in the g77 command that built
> fblas.so?  In the end, re-issuing just that command, slightly modifed so 
> there could be no mistake as to which libblas is was to find, seemed to fix
> my fblas.so.  So now  I can import blas.  
> I had thought that all I needed to do was edit site.cfg to indicate where
> the blas libraries were.  But somehow, it still looked elsewhere..
> I hope this helps anyone else who is a newbie at this and who runs into the 
> same problem. 

Can you give us the contents of your site.cfg, the locations of all of the
libblas's on your system, the output from your build, and the g77 command that
worked? That might help us to explain the problem at least, if not fix it.

Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
 that is made terrible by our own mad attempt to interpret it as though it had
 an underlying truth."
  -- Umberto Eco

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