[Numpy-discussion] Preliminary thoughts on implementing __matmul__

[cjw]

On 07/08/2014 5:40 AM, Sebastian Berg wrote:
> On Mi, 2014-08-06 at 14:05 -0700, Chris Barker wrote:
>> On Wed, Aug 6, 2014 at 8:32 AM, Charles R Harris
>> <charlesr.harris at gmail.com> wrote:
>>          Should also mention that we don't have the ability to operate
>>          on stacked vectors because they can't be identified by
>>          dimension info. One workaround is to add dummy dimensions
>>          where needed, another is to add two flags, row and col, and
>>          set them appropriately.
>>
>>
>> I've thought for ages that if you want to naturally do linear algebra,
>> you need to capture the concept of a row and column vector as distinct
>> from each-other and from (1,n) and (n,1) shape arrays. So:
It's a pity that these ideas weren't incorporatated into the Numarray 
implementation.

The treatment of the scalar was also questionable.

There's time to fix these things.
>>
> As a first thought I am against flags. We have dot, and vdot, which
> ideally would at some point do stacked matrix-matrix and stacked
> vector-vector (albeit vdot does complex conjugation). vector-matrix and
> matrix-vector would require the user to use (1, n) or (n, 1) matrices.
> If someone can convince me that this is a big deal, flags might be the
> only option, though...
That's a basic question:  Is dot a big deal?  Unfortunately, this wasn't 
examined carefully enough last Spring.
>
> - Sebastian
Colin W.
>
>> +1
>>
>>
>> -Chris
>>   
>>
>>
>> -- 
>>
>> Christopher Barker, Ph.D.
>> Oceanographer
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