[Numpy-discussion] dot!=matrixmultiply bug when dotblas is present

Fernando Perez Fernando.Perez at colorado.edu
Fri Oct 1 11:51:00 CDT 2004

Alexander Schmolck schrieb:
> Fernando Perez <Fernando.Perez at colorado.edu> writes:
>>Hi all,
>>I found something today a bit unpleasant: if you install numeric without
>>any BLAS support, 'matrixmultiply is dot==True', so they are fully
>>interchangeable.  However, to my surprise, if you build numeric with the blas
>>optimizations, they are NOT identical.  
> Oops, my bad (I submitted the patch and while pretty much all the real coding
> was done by Richard Everson this is my oversight).

No prob.  It's been fixed in Numeric 23.5, so no more worries.

>>Pretty significant difference...
> Yup, someone should incorporate optional atlas dot support into numarray if it
> hasn't happened already (won't be me, IIRC it took some convincing to get this
> into Numeric and I won't be using numarray for anything real in the near
> future).

I'll leave that question to the numarray guys, I have no idea where it stands 
in terms of blas/atlas support.  I certainly hope it has it or that this 
optimization can be brought in, as it makes a huge difference for the large 
array case.



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