[SciPy-user] Mathematica Element-wise Multiplication

Johann Cohen-Tanugi cohen@slac.stanford....
Mon Dec 17 01:49:38 CST 2007

Matthieu Brucher wrote:
> 2007/12/17, Johann Cohen-Tanugi <cohen@slac.stanford.edu 
> <mailto:cohen@slac.stanford.edu>>:
>     thanks for these precisions, David. Reading it, I still come to think
>     that it is a potential source of confusion to let a "row array" have a
>     transpose or T method, that essentially does nothing.
> In object oriented code, this can happen often, but it is not a 
> problem. It does what you want : inverse the axis, even if there is 
> only one axis.
hmmm...... okay... What I wanted was to transpose a 1D array into a 
vector, or vice-versa, with the linear algebra behavior in mind. I 
understand that numpy does not follow this, but I cannot believe that 
this behavior *is* what everybody wants! Tom's initial email was 
symptomatic, and Stefan's response, with the proposal to use the T 
method even more so!

Assuming that this natural linear algebra could be retrieved when, and 
*only* when, the array is 1D, I do not see how such an implementation 
could break codes that depend on it, because I don't see why someone 
would call 'a.T' just to have 'a' again.... But it is probably my lack 
of imagination.
Anyway, enough of this. I am sure the developers know better than me...


>     I guess there is a
>     reason behind this situation, but given the fact that it is there,
>     I am
>     wondering whether T or transpose of a row array could in fact return
>     what it is expected to, aka the 2d column array. Is there any
>     reason not
>     to have this functionality?
> More code in a simple function (thus slower) ? Breaking some code that 
> depend on it ? Not doing what the documentation says ?
> I think the method should not be changed, it does exactly what it says 
> it does. Changing its behaviour because of Matlab is not a good 
> solution, Python is not Matlab.
> Matthieu
> -- 
> French PhD student
> Website : http://matthieu-brucher.developpez.com/
> Blogs : http://matt.eifelle.com <http://matt.eifelle.com> and 
> http://blog.developpez.com/?blog=92
> LinkedIn : http://www.linkedin.com/in/matthieubrucher
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