[Numpy-discussion] Proposal: Chaining np.dot with mdot helper function

[Stefan Otte]

Hey guys,

I wrote myself a little helper function `mdot` which chains np.dot for
multiple arrays. So I can write

    mdot(A, B, C, D, E)

instead of these

    A.dot(B).dot(C).dot(D).dot(E)
    np.dot(np.dot(np.dot(np.dot(A, B), C), D), E)

I know you can use `numpy.matrix` to get nicer formulas. However, most
numpy/scipy function return arrays instead of numpy.matrix. Therefore,
sometimes you actually use array multiplication when you think you use
matrix multiplication. `mdot` is a simple way to avoid using
numpy.matrix but to improve the readability.

What do you think? Is this useful and worthy to integrate in numpy?


I already created an issuer for this:
https://github.com/numpy/numpy/issues/4311

jaimefrio also suggested to do some reordering of the arrays to
minimize computation:
https://github.com/numpy/numpy/issues/4311#issuecomment-35295857


Best,
 Stefan