On 2/9/2014 5:55 PM, alex wrote: > I'm working on the same kinds of problems in scipy development > (functions involving sparse matrices and abstract linear operators)
And how is numpy's matrix object getting in your way? Your initial post simply treated the desirability of deprecation as a given and did not lay out reasons. A strong reason would be e.g. if the matrix object is creating a serious maintenance headache. Eliminating this should be a big enough gain to offset any lost interest in numpy from users of Matlab, GAUSS, IDL etc. from the disappearance of a user-friendly notation. I accept that a numpy matrix has some warts. In the past, I've proposed changes to address these. E.g., https://www.mail-archive.com/numpy-discussion@scipy.org/msg06780.html However these went nowhere, so effectively the status quo was defended. I can live with that. A bit of the notational advantage of the `matrix` object was undercut by the addition of the `dot` method to arrays. If `matrix` is deprecated, I would hope that a matrix-power method would be added. (One that works correctly with boolean arrays and has a short name.) I ideally an inverse method would be added as well (with a short name). I think adding the hermitian transpose as `.H()` already has some support, but I forget its current status. Right now, to give a simple example, students can write a simple projection matrix as `X * (X.T * X).I * X.T` instead of `X.dot(la.inv(X.T.dot(X))).dot(X.T)`. The advantage is obvious and even bigger with more complex expressions. If we were to get `.I` for matrix inverse of an array (which I expect to be vociferously resisted) it would be `X.dot(X.T.dot(X).I).dot(X.T)` which at the moment I'm inclined to see as acceptable for teaching. (Not sure.) Just to forestall the usual "just start them with arrays, eventually they'll be grateful" reply, I would want to hear that suggestion only from someone who has used it successfully with undergraduates in the social sciences. Alan Isaac _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
