[Numpy-discussion] deprecate numpy.matrix

Alan G Isaac alan.isaac at gmail.com
Mon Feb 10 17:31:52 EST 2014

On 2/10/2014 5:11 PM, Pauli Virtanen wrote:
> The existence of np.matrix messes up the general agreement on ndarray
> semantics in Python. The meaning of very basic code such as
> 	A * B
> 	A.sum(0)
> 	A[0]
> where A and B are NxN matrices of some sort now depends on the types
> of A and B. This makes writing duck typed code impossible when both
> semantics are in play.

I'm just missing the point here; sorry.
Why isn't the right approach to require that
any object that wants to work with scipy
can be called  by `asarray` to guarantee
the core semantics? (And the matrix
object passes this test.)  For some objects
we can agree that `asarray` will coerce them.
(E.g., lists.)

I just do not see why scipy should care about
the semantics an object uses for interacting
with other objects of the same type.

Alan Isaac

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