WDgeev WDsbev WDstev WDsyev

WDsyev() Function WDsyev ( Jobz As  String, Uplo As  String, N As  Long, A As  Variant  ) Eigenvalues and eigenvectors of a symmetric matrix Purpose WDsyev computes all eigenvalues and, optionally, eigenvectors of a real symmetric matrix A. Returns N+1 x 1 (if Jobz = "N"), N+1 x N+1 (if Jobz = "V" and Info = 0) Column 1 Columns 2 to N+1 Rows 1 to N Eigenvalues in ascending order Eigenvectors (if Jobz = "V" and Info = 0) Row N+1 Return code 0 Return code = 0: Successful exit = i > 0): The i off-diagonal elements of an intermediate tridiagonal form did not converge to zero. Parameters [in] Jobz = "N": Compute eigenvalues only. = "V": Compute eigenvalues and eigenvectors. [in] Uplo = "U": Upper triangle of A is stored. = "L": Lower triangle of A is stored. [in] N Order of the matrix A. (N >= 1) [in] A (N x N) N x N symmetric matrix A. Reference LAPACK Example Compute all eigenvalues and eigenvectors of the symmetric matrix A, where ( 2.2 -0.11 -0.32 ) A = ( -0.11 2.93 0.81 ) ( -0.32 0.81 2.37 )