[Numpy-discussion] Scalar coercion
Travis Oliphant
oliphant at ee.byu.edu
Thu Mar 1 18:23:05 EST 2007
Robert Kern wrote:
>Travis Oliphant wrote:
>
>
>
>>So the question is: Do we keep the current behavior or change the
>>behavior to be more consistent with numarray. My current preference is
>>to change the behavior so it is more consistent with numarray (even
>>though it's actually not going to be trivial to do that).
>>
>>
>
>The current behavior is very obscure and almost never the behavior that one
>desires. Indeed, the first time it came up, you seemed to think it was a bug
>earlier in the thread before (presumably) you went into the code and
>rediscovered the justification.
>
>
What I discovered is that there wasn't really a justification at all,
except ease in coding using the current ufunc selection mechanism.
It's just that the code that makes the mixed scalar / array coercion do
the right thing in the case where both are the same type does not handle
the mixed type correctly.
There are really two places in the code where this is handled. One is
in the ufunc code where the "right" 1-d loop is determined and the
second is in the call PyArray_ConvertToCommonType.
The mechanisms used for determining the types of the outputs are coded
differently in each case.
So, I'm going to try and change this for the 1.0.2 release. It might
take me a little bit, so if anybody sees a way to do it, feel free to
chime in. I'm probably missing something obvious.
-Travis
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