Question: when are singular values and eigenvalues the same?
Answer: Thus, if X is N×N real symmetric matrix with non-negative eigenvalues, then eigenvalues and singular values coincide, but it is not generally the case! Given a matrix A, if the eigenvalues of AHA are λi≥0, then √λi are the singular values of A. If t is an eigenvalue of A, then |t| is a singular value of A.