Our analysis makes use of the following definition of matrix similarity: (2) Here tr(M) denotes the trace of the matrix M. tr(M 1 T M 1 ) computes the Frobenius norm ||M 1 || 2 , and tr(M 1 T M 2 ) is the Frobenius inner product.
cos(M 1 , M 2 ) computes the cosine similarity between the vectorized versions of matrices M 1 and M 2 .