hpevd#

chpevd

Functions

void chpevd(
    const char*          jobz,
    const char*          uplo,
    const INT            n,
          c64*  restrict AP,
          f32*  restrict W,
          c64*  restrict Z,
    const INT            ldz,
          c64*  restrict work,
    const INT            lwork,
          f32*  restrict rwork,
    const INT            lrwork,
          INT*  restrict iwork,
    const INT            liwork,
          INT*           info
);

void chpevd(const char *jobz, const char *uplo, const INT n, c64 *restrict AP, f32 *restrict W, c64 *restrict Z, const INT ldz, c64 *restrict work, const INT lwork, f32 *restrict rwork, const INT lrwork, INT *restrict iwork, const INT liwork, INT *info)#

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

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

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

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

inout

AP

COMPLEX*16 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 = ‘U’, AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j; if UPLO = ‘L’, 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.

out

W

DOUBLE PRECISION array, dimension (N). If INFO = 0, the eigenvalues in ascending order.

out

Z

COMPLEX*16 array, dimension (LDZ, N). 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.

in

ldz

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

out

work

COMPLEX*16 array, dimension (MAX(1,LWORK)). On exit, if INFO = 0, WORK(1) returns the required LWORK.

in

lwork

The dimension of array WORK. If N <= 1, LWORK must be at least 1. If JOBZ = ‘N’ and N > 1, LWORK must be at least N. If JOBZ = ‘V’ and N > 1, LWORK must be at least 2*N. If LWORK = -1, then a workspace query is assumed.

out

rwork

DOUBLE PRECISION array, dimension (MAX(1,LRWORK)). On exit, if INFO = 0, RWORK(1) returns the required LRWORK.

in

lrwork

The dimension of array RWORK. If N <= 1, LRWORK must be at least 1. If JOBZ = ‘N’ and N > 1, LRWORK must be at least N. If JOBZ = ‘V’ and N > 1, LRWORK must be at least 1 + 5*N + 2*N**2. If LRWORK = -1, then a workspace query is assumed.

out

iwork

INTEGER array, dimension (MAX(1,LIWORK)). On exit, if INFO = 0, IWORK(1) returns the required LIWORK.

in

liwork

The dimension of array IWORK. If JOBZ = ‘N’ or N <= 1, LIWORK must be at least 1. If JOBZ = ‘V’ and N > 1, LIWORK must be at least 3 + 5*N. If LIWORK = -1, then a workspace query is assumed.

out

info

= 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.

zhpevd