chpev

NAME

chpev - compute all the eigenvalues and, optionally, eigenvectors of a complex Hermitian matrix in packed storage

SYNOPSIS 

  SUBROUTINE CHPEV( JOBZ, UPLO, N, A, W, Z, LDZ, WORK, WORK2, INFO)
  CHARACTER * 1 JOBZ, UPLO
  COMPLEX A(*), Z(LDZ,*), WORK(*)
  INTEGER N, LDZ, INFO
  REAL W(*), WORK2(*)
 
  SUBROUTINE CHPEV_64( JOBZ, UPLO, N, A, W, Z, LDZ, WORK, WORK2, INFO)
  CHARACTER * 1 JOBZ, UPLO
  COMPLEX A(*), Z(LDZ,*), WORK(*)
  INTEGER*8 N, LDZ, INFO
  REAL W(*), WORK2(*)

F95 INTERFACE 

  SUBROUTINE HPEV( JOBZ, UPLO, [N], A, W, Z, [LDZ], [WORK], [WORK2], 
 *       [INFO])
  CHARACTER(LEN=1) :: JOBZ, UPLO
  COMPLEX, DIMENSION(:) :: A, WORK
  COMPLEX, DIMENSION(:,:) :: Z
  INTEGER :: N, LDZ, INFO
  REAL, DIMENSION(:) :: W, WORK2
 
  SUBROUTINE HPEV_64( JOBZ, UPLO, [N], A, W, Z, [LDZ], [WORK], [WORK2], 
 *       [INFO])
  CHARACTER(LEN=1) :: JOBZ, UPLO
  COMPLEX, DIMENSION(:) :: A, WORK
  COMPLEX, DIMENSION(:,:) :: Z
  INTEGER(8) :: N, LDZ, INFO
  REAL, DIMENSION(:) :: W, WORK2

C INTERFACE

#include <sunperf.h>

void chpev(char jobz, char uplo, int n, complex *a, float *w, complex *z, int ldz, int *info);

void chpev_64(char jobz, char uplo, long n, complex *a, float *w, complex *z, long ldz, long *info);

PURPOSE

chpev computes all the eigenvalues and, optionally, eigenvectors of a complex Hermitian matrix in packed storage.

ARGUMENTS

* JOBZ (input)
* UPLO (input)

* N (input)
The order of the matrix A. N >= 0.

* A (input/output)
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 A as follows: if UPLO = 'U', A(i + (j-1)*j/2) = A(i,j) for 1<=i<=j; if UPLO = 'L', A(i + (j-1)*(2*n-j)/2) = A(i,j) for j<=i<=n.

On exit, A is overwritten by values generated during the reduction to tridiagonal form. If UPLO = 'U', the diagonal and first superdiagonal of the tridiagonal matrix T overwrite the corresponding elements of A, and if UPLO = 'L', the diagonal and first subdiagonal of T overwrite the corresponding elements of A.

* W (output)
If INFO = 0, the eigenvalues in ascending order.

* Z (input)
If JOBZ = 'V', 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 = 'N', then Z is not referenced.

* LDZ (input)
The leading dimension of the array Z. LDZ >= 1, and if JOBZ = 'V', LDZ >= max(1,N).

* WORK (workspace)
dimension(MAX(1,2*N-1))

* WORK2 (workspace)
* INFO (output)