[Numpy-discussion] Have a problem: what is attribute 'compress'

Todd Miller jmiller at stsci.edu
Thu Dec 19 05:54:03 EST 2002

Sebastian Haase wrote:

>Somehow I have a problem with numarray. Please take a look at this:
Hi Sebastian,

I've don't recall seeing anything like this,  nor can I reproduce it 
now.   If you've been following numarray for a while now,  I can say 
that it is important to remove the old version of numarray before 
installing the new version.   I recommend deleting your current 
installation and reinstalling numarray.

compress() is a ufunc,  much like add() or put().  It is defined in 
ndarray.py,  right after the import of the modules ufunc and _ufunc.   
_ufunc in particular is a problematic module,  because it has followed 
the atypical development path of moving from C-code to Python code. 
 Because of this, and the fact that a .so or .dll overrides a .py, 
 older installations interfere with newer ones.  The atypical path was 
required because the original _ufuncmodule.c was so large that it could 
not be compiled on some systems;  as a result,  I split _ufuncmodule.c 
into pieces by data type and now use _ufunc.py to glue the pieces together.

Good luck!    Please let me know if reinstalling doesn't clear up the 


>>>>import numarray as na
>>>>na.array([0, 0])
>array([0, 0])
>>>>na.array([0.0, 0.0])
>Traceback (most recent call last):
>  File "<input>", line 1, in ?
>  File "C:\Python22\Lib\site-packages\numarray\numarray.py", line 581, in
>  File "C:\Python22\Lib\site-packages\numarray\arrayprint.py", line 163, in
>    separator, array_output)
>  File "C:\Python22\Lib\site-packages\numarray\arrayprint.py", line 125, in
>    format, item_length = _floatFormat(data, precision, suppress_small)
>  File "C:\Python22\Lib\site-packages\numarray\arrayprint.py", line 246, in
>    non_zero = numarray.abs(numarray.compress(numarray.not_equal(data, 0),
>AttributeError: 'module' object has no attribute 'compress'
>The same workes fine with Numeric. But I would prefer numarray because I'm
>writing C++-extensions and I need "unsigned shorts".
>What is this error about?
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