[Numpy-discussion] Detect subclass of ndarray

Travis Oliphant oliphant@ee.byu....
Sat Mar 24 15:02:59 CDT 2007


Alan G Isaac wrote:
> On Sat, 24 Mar 2007, Charles R Harris apparently wrote: 
>   
>> Yes, that is what I am thinking. Given that there are only the two 
>> possibilities, row or column, choose the only one that is compatible with 
>> the multiplying matrix. The result will not always be a column vector, for 
>> instance, mat([[1]])*ones(3) will be a 1x3 row vector. 
>>     
>
>
>
> Ack!  The simple rule `post multiply means its a column vector`
> would be horrible enough: A*ones(n)*B becomes utterly obscure.
> Now even that simple rule is to be violated??
>
> Down this path lies madness.
> Please, just raise an exception.
>   

My opinion is that a 1-d array in matrix-multiplication should always be 
interpreted as a row vector.  Is this not what is currently done?   If 
not, then it is a bug in my mind.

-Travis



More information about the Numpy-discussion mailing list