[Numpy-discussion] [OT] Starving CPUs article featured in IEEE's ComputingNow portal
Pauli Virtanen
pav at iki.fi
Mon Mar 22 15:42:55 EDT 2010
la, 2010-03-20 kello 17:36 -0400, Anne Archibald kirjoitti:
> I was in on that discussion. My recollection of the conclusion was
> that on the one hand they're useful, carefully applied, while on the
> other hand they're very difficult to reliably detect (since you don't
> want to forbid operations on non-overlapping slices of the same
> array).
I think one alternative brought up was
copy if unsure whether the slices overlap
which would make
A[whatever] = A[whatever2]
be always identical in functionality to
A[whatever] = A[whatever2].copy()
which is how things should work. This would permit optimizing simple
cases (at least 1D), and avoids running into NP-completeness (for numpy,
the exponential growth is however limited by NPY_MAXDIMS which is 64,
IIRC).
This would be a change in semantics, but in a very obscure corner that
hopefully nobody relies on.
--
Pauli Virtanen
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