[Numpy-discussion] feasability study to migrate from numarray to numpy

Travis Oliphant oliphant.travis at ieee.org
Mon Sep 18 13:58:26 CDT 2006

mg wrote:
> Hi all,
> I am doing a feseability study to migrate our Python based FEM 
> applications from Numarray to Numpy.
> First, I tried to install Numpy from Python-2.4 on linux-x86, 
> linux-86-64bit. So, all work fine. Great! Moreover, I change easily the 
> BLAS linked libraries. I tried with ATLAS and GOTO. Great again!
> Second, I try to do the same think on windows-x86 without success. So my 
> first question is: is Numpy-1.0b5 has been tested and is supported on 
> Windows?
Yes, it should work.  Builds for windows were provided.   But, perhaps 
there are configuration issues for your system that we are not handling 

> Third, I tried to install Numpy from Python-2.5, which is our standard 
> Python, on linux-x86... and the compilation stopped during the 
> compilation of core/src/multiarraymodule.c. So my second question is: is 
> there a workaround or is the porting to Python2.5 is yet schedule?
There was a problem with Python 2.5 and NumPy 1.0 that is fixed in SVN.  
Look for NumPy 1.0rc1 to come out soon.
> My third question is: is the tool to migrate the numarray based Python 
> scripts (numpy.numarray.alter_code1) work fine? (I suppose yes...)
It needs more testing.  It would be great if you could help us find and 
fix bugs in it.   I don't have a lot of numarray code to test.
> We have created a lot of bindings in order to pilote our generic-C++ 
> framework with Python scripts. So, about the Numpy API, is it widely 
> different than the Numarray API? (We will order the Numpy Guide too.)
It is more similar to the Numeric C-API.  However, the numarray C-API is 
completely supported by including numpy/libnumarray.h so you should be 
able to convert your C code very easily.   Any problems encountered 
should be noted and we'll get them fixed.
> To not duplicate large numerical memory arrays, Numarray allows to 
> aliasing the memory of some bindings with arrays from Numarray, and we 
> have used this feature intensively. So, I wonder if it is currently 
> supported (or even scheduled)?
I'm pretty sure the answer is yes (because the Numarray C-API is 
supported), though I'm not exactly sure what you mean.  Do you mean that 
you have memory created in the C/C++ framework and then you have an 
array use that memory for it's data area?  If that is what you mean, 
then the answer is definitely yes.


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