On Wed, Jun 26, 2019 at 10:24 PM Marten van Kerkwijk < m.h.vankerkwijk@gmail.com> wrote:
The main motivation for the @ PEP was actually to be able to get rid of
objects like np.matrix and scipy.sparse matrices that redefine the meaning of the * operator. Quote: "This PEP proposes the minimum effective change to Python syntax that will allow us to drain this swamp [meaning np.matrix & co]."
Notably, the @ PEP was written by Nathaniel, who was opposed to a copying .H.
I should note that my comment invoking the history of @ was about the regular transpose, .mT. The executive summary of the PEP includes the following relevant sentence: """ Currently, most numerical Python code uses * for elementwise multiplication, and function/method syntax for matrix multiplication; however, this leads to ugly and unreadable code in common circumstances. """
Exactly the same holds for matrix transpose, and indeed for many matrix expressions the gain in readability is lost without a clean option to do the transpose.
Yes, but that's not at all equivalent. The point for @ was that you cannot just create your own operator in Python. Therefore there really is no alternative to a builtin operator. For methods however, there's nothing stopping you from building a well-designed matrix class. You can then add all the new properties that you want. Ralf