[Numpy-discussion] New functions.
Wed Jun 1 11:29:50 CDT 2011
yes, and its probably slower to boot. A quick benchmark on my computer shows that:
a = np.zeros([4000,4000],'f4')+500
takes 0.02 secs
takes 0.1 secs
takes 0.06 secs
so casting the whole array is almost 40% faster than setting the accumulator type!, I would imagine having the type-casting being done on the fly during the mean computation would be even faster.
On Jun 1, 2011, at 9:11 AM, Bruce Southey wrote:
> On 06/01/2011 11:01 AM, Robert Kern wrote:
>> On Wed, Jun 1, 2011 at 10:44, Craig Yoshioka<email@example.com> wrote:
>>> would anyone object to fixing the numpy mean and stdv functions, so that they always used a 64-bit value to track sums, or so that they used a running calculation. That way
>>> would not equal 511.493408?
>> Yes, I object. You can set the accumulator dtype explicitly if you
>> need it: np.mean(arr, dtype=np.float64)
> Sure but fails to address that the output dtype of mean in this case is
> np.float64 which one would naively assume is also np.float64:
> Thus, we have:
> Tickets 465 and 518
> Various threads as well such as:
> NumPy-Discussion mailing list
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