Array and __rmul__ operator in Python Numpy

Question

In a project, I created a class, and I needed an operation between this new class and a real matrix, so I overloaded the __rmul__ function like this

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Answer 1

I could not explain the underlying problem as precise as Bakuriu, but there might be another solution.

You can force numpy to use your evaluation method by defining __array_priority__. As explained here in the numpy docs.

In your case you had to change your class definition to:

MAGIC_NUMBER = 15.0
# for the necessary lowest values of MAGIC_NUMBER look into the numpy docs
class foo(object):
    __array_priority__ = MAGIC_NUMBER
    aarg = 0

    def __init__(self):
        self.aarg = 1


    def __rmul__(self,A):
        print(A)
        return 0

    def __mul__(self,A):
        print(A)
        return 0