chpev (l) - Linux Manuals
chpev: computes all the eigenvalues and, optionally, eigenvectors of a complex Hermitian matrix in packed storage
Command to display chpev manual in Linux: $ man l chpev
NAME
CHPEV - computes all the eigenvalues and, optionally, eigenvectors of a complex Hermitian matrix in packed storage
SYNOPSIS
- SUBROUTINE CHPEV(
-
JOBZ, UPLO, N, AP, W, Z, LDZ, WORK, RWORK,
INFO )
-
CHARACTER
JOBZ, UPLO
-
INTEGER
INFO, LDZ, N
-
REAL
RWORK( * ), W( * )
-
COMPLEX
AP( * ), WORK( * ), Z( LDZ, * )
PURPOSE
CHPEV computes all the eigenvalues and, optionally, eigenvectors of a
complex Hermitian matrix in packed storage.
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.
- AP (input/output) COMPLEX array, dimension (N*(N+1)/2)
-
On entry, the upper or lower triangle of the Hermitian matrix
A, packed columnwise in a linear array. The j-th column of A
is stored in the array AP as follows:
if UPLO = aqUaq, AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j;
if UPLO = aqLaq, AP(i + (j-1)*(2*n-j)/2) = A(i,j) for j<=i<=n.
On exit, AP is overwritten by values generated during the
reduction to tridiagonal form. If UPLO = aqUaq, the diagonal
and first superdiagonal of the tridiagonal matrix T overwrite
the corresponding elements of A, and if UPLO = aqLaq, the
diagonal and first subdiagonal of T overwrite the
corresponding elements of A.
- W (output) REAL array, dimension (N)
-
If INFO = 0, the eigenvalues in ascending order.
- Z (output) COMPLEX array, dimension (LDZ, N)
-
If JOBZ = aqVaq, then if INFO = 0, Z contains the orthonormal
eigenvectors of the matrix A, with the i-th column of Z
holding the eigenvector associated with W(i).
If JOBZ = aqNaq, then Z is not referenced.
- LDZ (input) INTEGER
-
The leading dimension of the array Z. LDZ >= 1, and if
JOBZ = aqVaq, LDZ >= max(1,N).
- WORK (workspace) COMPLEX array, dimension (max(1, 2*N-1))
-
- RWORK (workspace) REAL array, dimension (max(1, 3*N-2))
-
- INFO (output) INTEGER
-
= 0: successful exit.
< 0: if INFO = -i, the i-th argument had an illegal value.
> 0: if INFO = i, the algorithm failed to converge; i
off-diagonal elements of an intermediate tridiagonal
form did not converge to zero.
Pages related to chpev
- chpev (3)
- chpevd (l) - computes all the eigenvalues and, optionally, eigenvectors of a complex Hermitian matrix A in packed storage
- chpevx (l) - computes selected eigenvalues and, optionally, eigenvectors of a complex Hermitian matrix A in packed storage
- chpcon (l) - estimates the reciprocal of the condition number of a complex Hermitian packed matrix A using the factorization A = U*D*U**H or A = L*D*L**H computed by CHPTRF
- chpgst (l) - reduces a complex Hermitian-definite generalized eigenproblem to standard form, using packed storage
- chpgv (l) - computes all the eigenvalues and, optionally, the eigenvectors of a complex generalized Hermitian-definite eigenproblem, of the form A*x=(lambda)*B*x, A*Bx=(lambda)*x, or B*A*x=(lambda)*x
- chpgvd (l) - computes all the eigenvalues and, optionally, the eigenvectors of a complex generalized Hermitian-definite eigenproblem, of the form A*x=(lambda)*B*x, A*Bx=(lambda)*x, or B*A*x=(lambda)*x
- chpgvx (l) - computes selected eigenvalues and, optionally, eigenvectors of a complex generalized Hermitian-definite eigenproblem, of the form A*x=(lambda)*B*x, A*Bx=(lambda)*x, or B*A*x=(lambda)*x
- chpmv (l) - performs the matrix-vector operation y := alpha*A*x + beta*y,