[Numpy-discussion] .T Transpose shortcut for arrays again

Robert Kern robert.kern at gmail.com
Thu Jul 6 13:54:29 CDT 2006


Travis Oliphant wrote:
> Bill Baxter wrote:
>> So in short my proposal is to:
>> --  make a.T a property of array that returns a.swapaxes(-2,-1),
>> --  make a.H a property of array that returns 
>> a.conjugate().swapaxes(-2,-1)
>> and maybe
>> --  make a.M a property of array that returns numpy.asmatrix(a)
> 
> I've tentatively implemented all of these suggestions as well as adding 
> the .A attribute to the ndarray as well (so that all sub-classes and 
> array scalars can get back a view as an ndarray). 
> 
> I did this to make it easier to do matrix-like calculations with or 
> with-out matrices.   Matrix-calculation flexibility is still a sore-spot 
> for many and I think these syntatical-sugar attributes will help long term.
> 
> If there are no strong objections, then the recent  MATH attribute 
> checkin will stay.  If there are major objections, then we can back them 
> out without too much trouble as well.

Like Sasha, I'm mildly opposed to .T (as a synonym for .transpose()) and much 
more opposed to the rest (including .T being a synonym for .swapaxes(-2, -1)). 
It's not often that a proposal carries with it its own slippery-slope argument 
against itself.

I don't think that just because arrays are often used for linear algebra that 
linear algebra assumptions should be built in to the core array type.

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
  that is made terrible by our own mad attempt to interpret it as though it had
  an underlying truth."
   -- Umberto Eco





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