[Numpy-discussion] matrix-related bug in 1.0b1

Sven Schreiber svetosch at gmx.net
Mon Jul 24 06:49:59 CDT 2006


Thanks for helping out on matrix stuff, Bill!

Bill Baxter schrieb:

> On 7/22/06, Sven Schreiber <svetosch at gmx.net> wrote:
>>
>> Note the array slicing works correct, but the equivalent thing with the
>> matrix does not.
> 
> Looks like it happened in rev 2698 of defmatrix.py, matrix.__getitem__
> method:
> 
>                if isscalar(index[1]):
>                    if isscalar(index[0]):
>                        retscal = True
>                    elif out.shape[0] == 1:
>                        sh = out.shape
>                        out.shape = (sh[1], sh[0])
>            ==> elif isinstance(index[1], (slice, types.EllipsisType)):
>            ==>     if out.shape[0] == 1 and not isscalar(index[0]):
> 
> It behaves like array if you remove the 'not' in the last line.
> But maybe that breaks some other cases?
> Maybe you can try making that change in your numpy/core/defmatrix.py
> (around line 140) and see if anything else breaks for you.
> 

Hm, I don't know -- if you don't mind I'd like to get a second opinion
before I mess around there. It's funny though that the changeset has the
title "fixing up matrix slicing" or something like that...


>>
>> Why is the direct access to matlib impossible?
> 
> Maybe the thinking is that since it's a compatibily module, if you
> want it you should explicity import it.  Like you have to do with
> oldnumeric.
> 

If that is the reason I can't really follow the logic, but I don't
really mind the status quo, either.

-sven




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