Should numpy.sqrt(-1) return 1j rather than nan?
Travis Oliphant
oliphant at ee.byu.edu
Wed Oct 11 17:19:58 CDT 2006
Fernando Perez wrote:
>On 10/11/06, Travis Oliphant <oliphant at ee.byu.edu> wrote:
>
>
>
>>pearu at cens.ioc.ee wrote:
>>
>>
>>>Could sqrt(-1) made to return 1j again?
>>>
>>>
>>>
>>Not in NumPy. But, in scipy it could.
>>
>>
>
>Without taking sides on which way to go, I'd like to -1 the idea of a
>difference in behavior between numpy and scipy.
>
>IMHO, scipy should be within reason a strict superset of numpy.
>
>
This was not the relationship of scipy to Numeric.
For me, it's the fact that scipy *used* to have the behavior that
scipy.sqrt(-1) return 1j
and now doesn't that is the kicker.
On the other hand requiring all calls to numpy.sqrt to go through an
"argument-checking" wrapper is a bad idea as it will slow down other uses.
So, I committed a change to scipy to bring it back into compatibility
with 0.3.2
>Gratuitious differences in behavior like this one are going to drive
>us all mad.
>
>There are people who import scipy for everything, others distinguish
>between numpy and scipy, others use numpy alone and at some point in
>their life's code they do
>
>import numpy as N -> import scipy as N
>
>because they start needing stuff not in plain numpy. Having different
>APIs and behaviors appear there is, I think, a Seriously Bad Idea
>(TM).
>
>
I think the SBI is mixing numpy and scipy gratuitously (which I admit I
have done in the past). I'm trying to repent....
-Travis
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