[Numpy-discussion] defmatrix.py

Colin J. Williams cjw@sympatico...
Tue Mar 27 13:10:57 CDT 2007


Charles R Harris wrote:
> 
> 
> On 3/26/07, *Travis Oliphant* <oliphant@ee.byu.edu 
> <mailto: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?

I hope so.  numarray used the row convention.

Colin W.
> 
> Chuck
> 
> 
> 
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