There is a useful connection between the Fisher Information Matrix I and SVD of the basis matrix B . Theory shows that, upon singular value decomposition of B , the matrix V contains the eigenvectors of T BB , while the diagonal elements of Σ are the square roots of the corresponding eigenvalues, so 2 Γ = Σ . According to Equation (2.3), I is proportional to the same product T BB . For the amplitude- only fitting problem, the eigenvalue decomposition of I is therefore related to the SVD of B as follows