zhbev zhbevd zhbevx zheev zheevd zheevr zheevx zhpev zhpevd zhpevx

zheev() void zheev ( char  jobz, char  uplo, int  n, int  lda, doublecomplex  a[], double  w[], doublecomplex  work[], int  lwork, double  rwork[], int *  info  ) (Simple driver) Eigenvalues and eigenvectors of a Hermitian matrix Purpose This routine computes all eigenvalues and, optionally, eigenvectors of a Hermitian matrix A. Eigenvalues and eigenvectors are computed by QL or QR method. 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 >= 0) (If n = 0, returns without computation) [in] lda The leading dimension of the array a[][]. (lda >= max(1,n)) [in,out] a[][] Array a[la][lda] (la >= n) [in] The Hermitian matrix A. If uplo = 'U', the leading n x n upper triangular part of a[][] contains the upper triangular part of the matrix A. If uplo = 'L', the leading n x n lower triangular part of a[][] contains the lower triangular part of the matrix A. [out] jobz = 'V': If info = 0, a[][] contains the orthonormal eigenvectors of the matrix A.   jobz = 'N': The lower triangle (if uplo = 'L') or the upper triangle (if uplo = 'U') of a[][], including the diagonal, is destroyed. [in] n x n Hermitian matrix A. The upper or lower triangular part is to be stored in accordance with uplo. [out] jobz = 'V': If info = 0, a[][] contains the orthonormal eigenvectors of the matrix A.   jobz = 'N': The lower triangle (if uplo = 'L') or the upper triangle (if uplo = 'U') of a[][], including the diagonal, is destroyed. Parameters [out] w[] Array w[lw] (lw >= n) If info = 0, the eigenvalues in ascending order. [out] work[] Array work[lwork] Work array. On exit, if info = 0, work[0] returns the optimal lwork. [in] lwork The size of work[] (lwork >= max(1, 2*n-1)) For optimal efficiency, lwork >= (nb + 1)*n, where nb is the optimal blocksize. If lwork = -1, then a workspace query is assumed. The routine only calculates the optimal size of the work[] array, and returns the value in work[0]. [out] rwork[] Array rwork[lrwork] (lrwork >= max(1, 3*n-2)) Work array. [out] info = 0: Successful exit = -1: The argument jobz had an illegal value (jobz != 'V' nor 'N') = -2: The argument uplo had an illegal value (uplo != 'U' nor 'L') = -3: The argument n had an illegal value (n < 0) = -4: The argument lda had an illegal value (lda < max(1, n)) = -8: The argument lwork had an illegal value (lwork too small) = i > 0: The algorithm failed to converge; i off-diagonal elements of an intermediate tridiagonal form did not converge to zero Reference LAPACK