On 25 October 2012 22:54, David Warde-Farley <warde...@iro.umontreal.ca>wrote:
> On Wed, Oct 24, 2012 at 7:18 AM, George Nurser <gnur...@gmail.com> wrote: > > Hi, > > > > I was just looking at the einsum function. > > To me, it's a really elegant and clear way of doing array operations, > which > > is the core of what numpy is about. > > It removes the need to remember a range of functions, some of which I > find > > tricky (e.g. tile). > > > > Unfortunately the present implementation seems ~ 4-6x slower than dot or > > tensordot for decent size arrays. > > I suspect it is because the implementation does not use blas/lapack > calls. > > > > cheers, George Nurser. > > Hi George, > > IIRC (and I haven't dug into it heavily; not a physicist so I don't > encounter this notation often), einsum implements a superset of what > dot or tensordot (and the corresponding BLAS calls) can do. So, I > think that logic is needed to carve out the special cases in which an > einsum can be performed quickly with BLAS. > Hi David, Yes, that's my reading of the situation as well. > Pull requests in this vein would certainly be welcome, but requires > the attention of someone who really understands how einsum works/can > work. > ...and I guess how to interface w BLAS/LAPACK. cheers, George. > > David > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@scipy.org > http://mail.scipy.org/mailman/listinfo/numpy-discussion >
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