heevd_2stage#

Functions

void cheevd_2stage(
    const char* jobz,
    const char* uplo,
    const INT   n,
          c64*  A,
    const INT   lda,
          f32*  W,
          c64*  work,
    const INT   lwork,
          f32*  rwork,
    const INT   lrwork,
          INT*  iwork,
    const INT   liwork,
          INT*  info
);
void cheevd_2stage(const char *jobz, const char *uplo, const INT n, c64 *A, const INT lda, f32 *W, c64 *work, const INT lwork, f32 *rwork, const INT lrwork, INT *iwork, const INT liwork, INT *info)#

CHEEVD_2STAGE computes all eigenvalues and, optionally, eigenvectors of a complex Hermitian matrix A using the 2stage technique for the reduction to tridiagonal.

If eigenvectors are desired, it uses a divide and conquer algorithm.

Parameters

in
jobz

= ‘N’: Compute eigenvalues only; = ‘V’: Compute eigenvalues and eigenvectors. Not available in this release.

in
uplo

= ‘U’: Upper triangle of A is stored; = ‘L’: Lower triangle of A is stored.

in
n

The order of the matrix A. N >= 0.

inout
A

Complex*16 array, dimension (lda, n). On entry, the Hermitian matrix A. On exit, if JOBZ = ‘V’, then if INFO = 0, A contains the orthonormal eigenvectors of the matrix A.

in
lda

The leading dimension of the array A. lda >= max(1,n).

out
W

Single precision array, dimension (n). If INFO = 0, the eigenvalues in ascending order.

out
work

Complex*16 array, dimension (max(1,lwork)). On exit, if INFO = 0, work[0] returns the optimal lwork.

in
lwork

The dimension of the array work.

out
rwork

Single precision array, dimension (lrwork). On exit, if INFO = 0, rwork[0] returns the optimal lrwork.

in
lrwork

The dimension of the array rwork.

out
iwork

Integer array, dimension (max(1,liwork)). On exit, if INFO = 0, iwork[0] returns the optimal liwork.

in
liwork

The dimension of the array iwork.

out
info

= 0: successful exit < 0: if info = -i, the i-th argument had an illegal value > 0: if info = i and JOBZ = ‘N’, then the algorithm failed to converge; i off-diagonal elements of an intermediate tridiagonal form did not converge to zero; if info = i and JOBZ = ‘V’, then the algorithm failed to compute an eigenvalue while working on the submatrix lying in rows and columns INFO/(N+1) through mod(INFO,N+1).

Functions

void zheevd_2stage(
    const char* jobz,
    const char* uplo,
    const INT   n,
          c128* A,
    const INT   lda,
          f64*  W,
          c128* work,
    const INT   lwork,
          f64*  rwork,
    const INT   lrwork,
          INT*  iwork,
    const INT   liwork,
          INT*  info
);
void zheevd_2stage(const char *jobz, const char *uplo, const INT n, c128 *A, const INT lda, f64 *W, c128 *work, const INT lwork, f64 *rwork, const INT lrwork, INT *iwork, const INT liwork, INT *info)#

ZHEEVD_2STAGE computes all eigenvalues and, optionally, eigenvectors of a complex Hermitian matrix A using the 2stage technique for the reduction to tridiagonal.

If eigenvectors are desired, it uses a divide and conquer algorithm.

Parameters

in
jobz

= ‘N’: Compute eigenvalues only; = ‘V’: Compute eigenvalues and eigenvectors. Not available in this release.

in
uplo

= ‘U’: Upper triangle of A is stored; = ‘L’: Lower triangle of A is stored.

in
n

The order of the matrix A. N >= 0.

inout
A

Complex*16 array, dimension (lda, n). On entry, the Hermitian matrix A. On exit, if JOBZ = ‘V’, then if INFO = 0, A contains the orthonormal eigenvectors of the matrix A.

in
lda

The leading dimension of the array A. lda >= max(1,n).

out
W

Double precision array, dimension (n). If INFO = 0, the eigenvalues in ascending order.

out
work

Complex*16 array, dimension (max(1,lwork)). On exit, if INFO = 0, work[0] returns the optimal lwork.

in
lwork

The dimension of the array work.

out
rwork

Double precision array, dimension (lrwork). On exit, if INFO = 0, rwork[0] returns the optimal lrwork.

in
lrwork

The dimension of the array rwork.

out
iwork

Integer array, dimension (max(1,liwork)). On exit, if INFO = 0, iwork[0] returns the optimal liwork.

in
liwork

The dimension of the array iwork.

out
info

= 0: successful exit < 0: if info = -i, the i-th argument had an illegal value > 0: if info = i and JOBZ = ‘N’, then the algorithm failed to converge; i off-diagonal elements of an intermediate tridiagonal form did not converge to zero; if info = i and JOBZ = ‘V’, then the algorithm failed to compute an eigenvalue while working on the submatrix lying in rows and columns INFO/(N+1) through mod(INFO,N+1).