How to replicate a matrix into a cube in Armadillo or RcppArmadillo

Question

I have a matrix (say A) of dimension (k1, k2). I want to replicate it N times and save it into a 3D array or cube called B. As a result, the dimension of B will be (k1, k2, N).

In R, I did the following to do that:

B <- replicate(N, A)

I wonder if there is a function in Armadillo that can do that. Or, is looping the only way?

Thank you!

you should probably initialize the cube then fill it – Onyambu Jul 02 '21 at 15:32 — Onyambu, Jul 02 '21 at 15:32

score 3 · Answer 1 · answered Jul 05 '21 at 22:35

3

You could avoid using a loop with the each_slice() method, but the cube must still be initialized beforehand:

arma::cube B(k1, k2, N);
B.each_slice() = A;

which has the advantage of conciseness.

answered Jul 05 '21 at 22:35

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How to replicate a matrix into a cube in Armadillo or RcppArmadillo

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