This matrix is not simply a combination of nine unrelated values, but rather a set of components which must satisfy both the properties that the matrix is symmetric (V ij = V ji ) and that the trace is 0 (V 11 + V 22 + V 33 = 0). Therefore, while every EFG tensor can be written as a (3 × 3) matrix, not every (3×3) matrix is a valid tensor. In other words, any (3×3) matrix that we might predict from ML methods, which does not have these properties, violates the basic underlying physical properties of the system.