[Numpy-discussion] bincount limitations

Skipper Seabold jsseabold@gmail....
Thu Jun 2 12:08:32 CDT 2011

On Wed, Jun 1, 2011 at 10:10 PM, Alan G Isaac <alan.isaac@gmail.com> wrote:
>> On Thu, Jun 2, 2011 at 1:49 AM, Mark Miller<markperrymiller@gmail.com>  wrote:
>>> Not quite. Bincount is fine if you have a set of approximately
>>> sequential numbers. But if you don't....
> On 6/1/2011 9:35 PM, David Cournapeau wrote:
>> Even worse, it fails miserably if you sequential numbers but with a high shift.
>> np.bincount([100000001, 100000002]) # will take a lof of memory
>> Doing bincount with dict is faster in those cases.
> Since this discussion has turned shortcomings of bincount,
> may I ask why np.bincount([]) is not an empty array?
> Even more puzzling, why is np.bincount([],minlength=6)
> not a 6-array of zeros?

Just looks like it wasn't coded that way, but it's low-hanging fruit.
Any objections to adding this behavior? This commit should take care
of it. Tests pass. Comments welcome, as I'm just getting my feet wet



More information about the NumPy-Discussion mailing list