cheev (l)  Linux Manuals
cheev: computes all eigenvalues and, optionally, eigenvectors of a complex Hermitian matrix A
Command to display cheev
manual in Linux: $ man l cheev
NAME
CHEEV  computes all eigenvalues and, optionally, eigenvectors of a complex Hermitian matrix A
SYNOPSIS
 SUBROUTINE CHEEV(

JOBZ, UPLO, N, A, LDA, W, WORK, LWORK, RWORK,
INFO )

CHARACTER
JOBZ, UPLO

INTEGER
INFO, LDA, LWORK, N

REAL
RWORK( * ), W( * )

COMPLEX
A( LDA, * ), WORK( * )
PURPOSE
CHEEV computes all eigenvalues and, optionally, eigenvectors of a
complex Hermitian matrix A.
ARGUMENTS
 JOBZ (input) CHARACTER*1

= aqNaq: Compute eigenvalues only;
= aqVaq: Compute eigenvalues and eigenvectors.
 UPLO (input) CHARACTER*1

= aqUaq: Upper triangle of A is stored;
= aqLaq: Lower triangle of A is stored.
 N (input) INTEGER

The order of the matrix A. N >= 0.
 A (input/output) COMPLEX array, dimension (LDA, N)

On entry, the Hermitian matrix A. If UPLO = aqUaq, the
leading NbyN upper triangular part of A contains the
upper triangular part of the matrix A. If UPLO = aqLaq,
the leading NbyN lower triangular part of A contains
the lower triangular part of the matrix A.
On exit, if JOBZ = aqVaq, then if INFO = 0, A contains the
orthonormal eigenvectors of the matrix A.
If JOBZ = aqNaq, then on exit the lower triangle (if UPLO=aqLaq)
or the upper triangle (if UPLO=aqUaq) of A, including the
diagonal, is destroyed.
 LDA (input) INTEGER

The leading dimension of the array A. LDA >= max(1,N).
 W (output) REAL array, dimension (N)

If INFO = 0, the eigenvalues in ascending order.
 WORK (workspace/output) COMPLEX array, dimension (MAX(1,LWORK))

On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
 LWORK (input) INTEGER

The length of the array WORK. LWORK >= max(1,2*N1).
For optimal efficiency, LWORK >= (NB+1)*N,
where NB is the blocksize for CHETRD returned by ILAENV.
If LWORK = 1, then a workspace query is assumed; the routine
only calculates the optimal size of the WORK array, returns
this value as the first entry of the WORK array, and no error
message related to LWORK is issued by XERBLA.
 RWORK (workspace) REAL array, dimension (max(1, 3*N2))

 INFO (output) INTEGER

= 0: successful exit
< 0: if INFO = i, the ith argument had an illegal value
> 0: if INFO = i, the algorithm failed to converge; i
offdiagonal elements of an intermediate tridiagonal
form did not converge to zero.
Pages related to cheev
 cheev (3)
 cheevd (l)  computes all eigenvalues and, optionally, eigenvectors of a complex Hermitian matrix A
 cheevr (l)  computes selected eigenvalues and, optionally, eigenvectors of a complex Hermitian matrix A
 cheevx (l)  computes selected eigenvalues and, optionally, eigenvectors of a complex Hermitian matrix A
 cheequb (l)  computes row and column scalings intended to equilibrate a symmetric matrix A and reduce its condition number (with respect to the twonorm)
 checon (l)  estimates the reciprocal of the condition number of a complex Hermitian matrix A using the factorization A = U*D*U**H or A = L*D*L**H computed by CHETRF
 chegs2 (l)  reduces a complex Hermitiandefinite generalized eigenproblem to standard form
 chegst (l)  reduces a complex Hermitiandefinite generalized eigenproblem to standard form
 chegv (l)  computes all the eigenvalues, and optionally, the eigenvectors of a complex generalized Hermitiandefinite eigenproblem, of the form A*x=(lambda)*B*x, A*Bx=(lambda)*x, or B*A*x=(lambda)*x