WZgeev WZgeev2 WZhbev WZhbev2 WZheev WZheev2

WZheev() Function WZheev ( Jobz As  String, Uplo As  String, N As  Long, A As  Variant  ) Eigenvalues and eigenvectors of a Hermitian matrix (complex number representation in Excel format) Purpose WZheev computes all eigenvalues and, optionally, eigenvectors of a Hermitian matrix A. To represent complex numbers in Excel cells, complex number format in Excel (e.g. 2.5+1i) is used. Worksheet function Complex can be used to input complex numbers into cells. 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 Hermitian matrix A. Reference LAPACK Example Compute all eigenvalues and eigenvectors of the Hermitian matrix A, where ( 0.20 -0.11+0.93i 0.81-0.37i ) A = ( -0.11-0.93i -0.32 -0.80+0.92i ) ( 0.81+0.37i -0.80-0.92i -0.29 )