[Numpy-discussion] Numarray-0.2 issues with GCC and SPARC

Todd Miller jmiller at stsci.edu
Thu Feb 28 16:01:03 EST 2002


I'm Todd Miller and I work at STSCI on Numarray.  Two people have 
reported problems with compiling Numarray-0.11 or 0.2 with GCC on SPARC. 
 There are two problems:

1. Compiling the _ufuncmodule.c using gcc-2.95 on a SPARC (with the 
default switches) uses tons of virtual memory and typically fails.  

a. This can be avoided by adding the compilation flags:
    EXTRA_COMPILE_ARGS=["-O0", "-Wno-return-type"]
to your setup.py when compiling *numarray*.  

b. Alternately, you can wait for numarray-0.3 which will partition the 
ufuncmodule into smaller compilation units.   We suspect these will 
avoid the problem naturally and permit the use of optimization.

c. Lastly, if you have Sun cc, you might want to try using it instead of 
gcc.  This is what we do at STSCI.  You need to recompile Python itself 
if you want to do this and your python was already compiled with gcc.

2. Python compiled with gcc generates misaligned storage within buffer 
objects.  Numarray-0.2 is dependent on the problematic variant of the 
buffer object so if you want to use Float64 or Complex128 on a SPARC you 
may experience core dumps.  

a. I have a non-portable patch which worked for me with gcc-2.95 on 
SPARC.   I can e-mail this to anyone interested.  Apply this patch and 
recompile *python*.

b. You might be able to fix this with gcc compilation switches for Python:
try -munaligned-doubles and recompile *python*.

c. Numarray-0.3 will address this issue by providing its own minimal 
memory object which features correctly aligned storage.  This solution 
will not require recompiling python, but won't be available until 

d. Python compiled with Sun cc using the default switches doesn't 
manifest this bug.  If you have Sun cc,  you may want to recompile 
*python* using that.

In general,  I think the "better part of valor" is probably to wait 3 
weeks for numarray-0.3 when both issues should be addressed.  If you 
want to try numarray-0.2 now with GCC on a SPARC,  I hope some of these 
ideas work for you.


Todd Miller 			jmiller at stsci.edu
STSCI / SSG			(410) 338 4576

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