Efficient matrix indexing in Numpy

Question

I have a matrix A of size 256 X 16, and a second matrix B of size 8 X 8, where every element of B is an integer in the range [0, 15]. If A was just a row vector (i.e. of size 1X16) then C = A[B] would output an 8X8 matrix where Cij = A[bij]. Is there any efficient way I could do the same if A is 256X16 using numpy (or anything else)? I mean that I want an output matrix C of size 256 X 8 X 8 (i.e., B is indexing every row of A). Thanks!

yatu · Accepted Answer · 2020-04-08 09:00:38Z

1

Ok, I think that I solved it:

C = A[:, B]

edited Apr 8, 2020 at 9:00

yatu

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answered Apr 8, 2020 at 8:59

MRm

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