[Numpy-discussion] defmatrix.py

Charles R Harris charlesr.harris@gmail....
Mon Mar 26 18:07:52 CDT 2007


On 3/26/07, Travis Oliphant <oliphant@ee.byu.edu> wrote:
>
> Charles R Harris wrote:
>
> >
> >
> >     The rule 1-d is always a *row* vector only applies when converting
> >     to a
> >     matrix.
> >
> >     In this case, the dot operator does not "convert to a matrix" but
> >     uses
> >     rules for operating with mixed 2-d and 1-d arrays inherited from
> >     Numeric.
> >
> >     I'm very hesitant to change those rules.
> >
> >
> > I wasn't suggesting that, just noticing that the rule was 1-d vector
> > on right is treated as a column vector by dot, which is why an
> > exception was raised in the posted case. If it is traditional for
> > matrix routines always treat is as a row vector, so be it.
>
> O.K.  So, the problem is that when I defined matrix multiplication, I
> mistakenly believed that dot always interpreted 1-d arrays as row
> vectors which it is now clear it doesn't.
>
> I think this led to the issues.
>
> So, making dot always return arrays seems like the needed fix.


Sounds good. Do you want to leave the matrix  * operator as it now is?

Chuck
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