I tried to figure it out myself but I just don’t get the summation right. I have an (n ,d^2,m) Tensor A and an (n ,d  , m )  tensor B. I want the following summation result C  (with size  (n ,d  , m)  )
C[i,j,k] = A[i,:,k]B[i,:,k][j]
where the last product is meant as a matrix multiplication (the second dimension has to split into 2 of size d). How do I achieve this?