[Numpy-discussion] inplace dot products
Fri Feb 20 05:39:49 CST 2009
Olivier Grisel wrote:
> 2009/2/20 David Warde-Farley <firstname.lastname@example.org>:
>> Hi Olivier,
>> There was this idea posted on the Scipy-user list a while back:
>> but it doesn't look like he got anywhere with it, or even got a
>> I just tried it and I observe the same behaviour. A quick look at the
>> SciPy sources tells me there is something fishy.
>> ! c = gemm(alpha,a,b,beta=0,c=0,trans_a=0,trans_b=0,overwrite_c=0)
>> ! Calculate C <- alpha * op(A) * op(B) + beta * C
>> I don't read Fortran very well, but it seems to me as though the
>> Fortran prototype doesn't match the python prototype.
>> I'll poke around a little more, but in summary: there's no numpy-
>> sanctioned way to specify an output array for a dot(), AFAIK. This is
>> a bit of an annoyance, I agree, though I seem to remember Robert Kern
>> offering a fairly compelling argument why it's hard. I just don't know
>> what that argument is :)
> Alright, thanks for the reply.
> Is there a canonical way /sample code to gain low level access to blas / lapack
> atlas routines using ctypes from numpy / scipy code?
You can just use ctypes to access ATLAS, as you would do for any
library. Or do you mean something else ?
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