[Numpy-discussion] defmatrix.py

[Travis Oliphant]

Charles R Harris wrote:

>
>
> On 3/26/07, *Travis Oliphant* <oliphant at ee.byu.edu 
> <mailto:oliphant at ee.byu.edu>> wrote:
>
>     Charles R Harris wrote:
>
>     >
>     >
>     > On 3/26/07, *Nils Wagner* <nwagner at iam.uni-stuttgart.de
>     <mailto:nwagner at iam.uni-stuttgart.de>
>     > <mailto: nwagner at iam.uni-stuttgart.de
>     <mailto:nwagner at iam.uni-stuttgart.de>>> wrote:
>     >
>     >     Charles R Harris wrote:
>     >     >
>     >     >
>     >     > On 3/25/07, *Nils Wagner* <nwagner at iam.uni-stuttgart.de
>     <mailto:nwagner at iam.uni-stuttgart.de>
>     >     <mailto:nwagner at iam.uni-stuttgart.de
>     <mailto:nwagner at iam.uni-stuttgart.de>>
>     >     > <mailto: nwagner at iam.uni-stuttgart.de
>     <mailto:nwagner at iam.uni-stuttgart.de>
>     >     <mailto:nwagner at iam.uni-stuttgart.de
>     <mailto:nwagner at iam.uni-stuttgart.de>>>> wrote:
>     >     >
>     >     >     Hi,
>     >     >
>     >     >
>     >
>     >  <snip>
>     >
>     > Ok, things should be working now. In order to get rid of the scipy
>     > problems I just needed to rm the scipy package in site-packages and
>     > then reinstall.
>     >
>     > I still need to figure out a real fix down in the dot routine
>     because
>
>
>     No, don't fix the dot routine.  Remember the dot routine should accept
>     mixed 2-d arrays and 1-d arrays because it is more general than matrix
>     multiplication.
>
>
> Sure, but it can't return a row vector when multiplying a 1-d vector. 
> It just ain't mathematically possible no matter how the 1-d vector is 
> interpreted. It needs to return either a column vector or a 1-d vector.

Ah.. I see what your point is. 

How to fix that.   The problem is choosing the Python type of the output 
array.  It's being selected as matrix right now because of the 
precedence of the matrix subtype, but it should be chosen as array in 
this instance.    Perhaps we should make dot always choose the array as 
the output type??

-Travis