On Mon, Mar 17, 2014 at 3:48 PM, Nathaniel Smith <n...@pobox.com> wrote: > On Sat, Mar 15, 2014 at 7:01 PM, Alexander Belopolsky <ndar...@mac.com> wrote:
>> One more question that I think should be answered by the PEP and may >> influence the associativity decision is what happens if in an A @ B @ C >> expression, each operand has its own type that defines __matmul__ and >> __rmatmul__? For example, A can be an ndarray, B a sympy expression and C a >> pyoperator. > > The general rule in Python is that in a binary operation A # B, then > first we try A.__special__, and if that doesn't exist or it returns > NotImplemented, then we try B.__rspecial__. (The exception is that if > B.__class__ is a proper subclass of A.__class__, then we do it in the > reverse order.) Assuming that all combinations are possible and give no error: A @ B @ C == A.__matmul__(B.__matmul__(C)) # right A @ B @ C == A.__matmul__(B).__matmul__(C) # left Did you want to specify which permutations of X.__matmul__(Y) return NotImplemented? -- Robert Kern _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
