[Numpy-discussion] users point of view and ufuncs

Sebastian Haase haase at msg.ucsf.edu
Fri Aug 25 10:34:25 CDT 2006


Sasha wrote:
> On 8/25/06, Charles R Harris <charlesr.harris at gmail.com> wrote:
>> Matrix rank has nothing to do with numpy rank. Numpy rank is simply the
>> number of indices required to address an element of an ndarray. I always
>> thought a better name for the Numpy rank would be dimensionality, but like
>> everything else one gets used to the numpy jargon, it only needs to be
>> defined someplace for what it is.
> 
> That's my point exactly.  The rank(2) definition was added by
> Sebastian Haase who advocates the use of the term "ndims" instead of
> "rank".  I've discussed the use of "dimentionality' in the preamble.
> Note that ndims stands for the number of dimensions, not
> dimensionality.
> 
> I don't want to remove rank(2) without hearing from Sebastian first
> and I appreciate his effort to improve the glossary. Maybe we shold
> add a "matrix rank" entry instead.


My phasing is certainly suboptimal (I only remember the German wording - 
and even that only faintly - "linear independent" !?)

But I put it in, remembering the discussion in "numpy" on *why*
array.rank (numarray) was changed to array.ndim (numpy)
I just thought this page might be a good place to 'discourage usage
of badly-defined terms' or at least give the argument for "ndim".

[ OK: it's not "badly" defined: but there are two separate camps on 
*what* it should mean --- ndim is clear.]

BTW: Does the "matrix" class have m.rank attribute !?

Cheers,
Sebastian.




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