Hopefully something in the tensor module could help you here (I'll
defer that to someone more knowledgeable). Otherwise you'd need
something like MatrixFunction (which isn't implemented yet,
https://github.com/sympy/sympy/issues/5855), i.e., to represent the
matrices as functions of i and j.
Aaron
Greetings,
I am using sympy for the first time, and attempting to do matrix
multiplication like the following
sum_{l,m} U[i,l] G[l,m] D[j,m]
I want to do regular matrix multiplication, but only on one of the two
indices for the objects U and D, in my case for a known G (I want to put
numerica
