[Numpy-discussion] generalized_inverse

Victoria G. Laidler laidler at stsci.edu
Fri Jul 14 11:16:58 CDT 2006


Jonathan Taylor wrote:

> pseudoinverse
>
> it's the same name matlab uses:
>
> http://www.mathworks.com/access/helpdesk/help/techdoc/ref/pinv.html

Thanks for the explanation.

I'm puzzled by the naming choice, however. Standard best practice in 
writing software is to give understandable names, to improve readability 
and code maintenance. Obscure abbreviations like "pinv" pretty much went 
out with the FORTRAN 9-character limit for variable names. It's very 
unusual to see them in new software nowadays, and it always looks 
unprofessional to me.

I understand that for interactive use, short names are more convenient; 
but shouldn't they be available aliases to the more general names? Since 
numpy is primarily a software library, I wouldn't expect it to sacrifice 
a standard best-practice in order to make things more convenient for 
interactive use.

If the concern is for for matlab compatibility, maybe a synonym module 
numpy.as_matlab could define all the synonyms, that matlab users could 
then use? That would make more sense to me than inflicting obscure 
matlab names on the rest of the user community.

Vicki Laidler



>
> Victoria G. Laidler wrote:
>
>> Sven Schreiber wrote:
>>
>>  
>>
>>> Jon Peirce schrieb:
>>>
>>>
>>>   
>>>
>>>> There used to be a function generalized_inverse in the numpy.linalg 
>>>> module (certainly in 0.9.2).
>>>>
>>>> In numpy0.9.8 it seems to have been moved to the numpy.linalg.old 
>>>> subpackage. Does that mean it's being dropped? Did it have to move? 
>>>> Now i have to add code to my package to try both locations because 
>>>> my users might have any version... :-(
>>>>
>>>>
>>>>  
>>>>     
>>>
>>> Maybe I don't understand, but what's wrong with numpy.linalg.pinv?
>>>
>>>
>>>   
>>
>> Er, what's a pinv? It doesn't sound anything like a generalized_inverse.
>>
>> Vicki Laidler
>>
>>
>>
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>





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