[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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