[SciPy-user] BLAS and srotgm

Robert Kern robert.kern@gmail....
Wed Oct 10 10:10:53 CDT 2007


Donna Calhoun wrote:
>>> I removed the library flags to libc, and libutil and the build picked up the
>>> correct blas library.> 
>> I'm curious as to why you had -L/usr/lib in there. Did it come from Python's
>> build or do you have an LDFLAGS environment variable sitting around that's
>> interfering?
> 
> (sorry for the long delay in a reply) 
> 
> Yes, I had added /usr/lib to my LDFLAGS environment variable.  Before I 
> figured out that I needed the "-shared" flag, I was getting lots of undefined
> references to things from posix libraries, etc.   So I added references to c
> libs.  But then I came across a post that hinted at the "-shared" flag, and that
> solved all the undefined references problems.  
> 
> If in fact, the "-shared" flag is required, is there a mention of this 
> somewhere in the install instructions?  It took me two days to figure 
> out what the problem was.
> 
> I was installing version 0.5.2.1.  I have since gone on to install 0.6.0 on
> another machine, and it seems as though this version didn't need the flag
> (although I don't remmber exactly whether I may have in fact had it set).   Did
> anything change from the last version to this one?  For some reason, I didn't
> need this flag with numpy. 

The problem is that you set LDFLAGS, which *overrides* the linking arguments for
FORTRAN extension modules, even the flags that are added by Python itself like
-shared. If you leave it unset, things should be fine. Using site.cfg is the
appropriate way to add the usual -L and -l flags.

-- 
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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