How to apply arithmetic with shifted/rolled indices

[David Hummel]

Hi - I am new to EJML and am trying to efficiently apply operations on two dense matrices where the indices of operation might be like f(A(i,j),B(i+1,j)).  Either through rolling the i index back to 0 or using a second operation on the two side columns, I would need to complete the operation.

How would one recommend doing this performantly?

Thanks!