[Numpy-discussion] optimizing ndarray.__setitem__
Christoph Groth
cwg at falma.de
Wed May 4 09:19:20 EDT 2011
Dear numpy experts,
I have noticed that with Numpy 1.5.1 the operation
m[::2] += 1.0
takes twice as long as
t = m[::2]
t += 1.0
where "m" is some large matrix. This is of course because the first
snippet is equivalent to
t = m[::2]
t += 1.0
m[::2] = t
I wonder whether it would not be a good idea to optimize
ndarray.__setitem__ to not execute an assignment of a slice onto itself.
Is there any good reason why this is not being done already?
best,
Christoph
More information about the NumPy-Discussion
mailing list