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zhbgvd (3p)

Name

zhbgvd - compute all the eigenvalues, and optionally, the eigenvectors of a complex generalized Hermitian-definite banded eigenproblem, of the form A*x=(lambda)*B*x

Synopsis

SUBROUTINE ZHBGVD(JOBZ, UPLO, N, KA, KB, AB, LDAB, BB, LDBB, W, Z,
LDZ, WORK, LWORK, RWORK, LRWORK, IWORK, LIWORK, INFO)

CHARACTER*1 JOBZ, UPLO
DOUBLE COMPLEX AB(LDAB,*), BB(LDBB,*), Z(LDZ,*), WORK(*)
INTEGER N, KA, KB, LDAB, LDBB, LDZ, LWORK, LRWORK, LIWORK, INFO
INTEGER IWORK(*)
DOUBLE PRECISION W(*), RWORK(*)

SUBROUTINE ZHBGVD_64(JOBZ, UPLO, N, KA, KB, AB, LDAB, BB, LDBB, W, Z,
LDZ, WORK, LWORK, RWORK, LRWORK, IWORK, LIWORK, INFO)

CHARACTER*1 JOBZ, UPLO
DOUBLE COMPLEX AB(LDAB,*), BB(LDBB,*), Z(LDZ,*), WORK(*)
INTEGER*8 N, KA, KB, LDAB, LDBB, LDZ, LWORK, LRWORK, LIWORK, INFO
INTEGER*8 IWORK(*)
DOUBLE PRECISION W(*), RWORK(*)




F95 INTERFACE
SUBROUTINE HBGVD(JOBZ, UPLO, N, KA, KB, AB, LDAB, BB, LDBB, W,
Z, LDZ, WORK, LWORK, RWORK, LRWORK, IWORK, LIWORK,
INFO)

CHARACTER(LEN=1) :: JOBZ, UPLO
COMPLEX(8), DIMENSION(:) :: WORK
COMPLEX(8), DIMENSION(:,:) :: AB, BB, Z
INTEGER :: N, KA, KB, LDAB, LDBB, LDZ, LWORK, LRWORK, LIWORK, INFO
INTEGER, DIMENSION(:) :: IWORK
REAL(8), DIMENSION(:) :: W, RWORK

SUBROUTINE HBGVD_64(JOBZ, UPLO, N, KA, KB, AB, LDAB, BB, LDBB,
W, Z, LDZ, WORK, LWORK, RWORK, LRWORK, IWORK, LIWORK,
INFO)

CHARACTER(LEN=1) :: JOBZ, UPLO
COMPLEX(8), DIMENSION(:) :: WORK
COMPLEX(8), DIMENSION(:,:) :: AB, BB, Z
INTEGER(8) :: N, KA, KB, LDAB, LDBB, LDZ, LWORK, LRWORK, LIWORK, INFO
INTEGER(8), DIMENSION(:) :: IWORK
REAL(8), DIMENSION(:) :: W, RWORK




C INTERFACE
#include <sunperf.h>

void  zhbgvd(char jobz, char uplo, int n, int ka, int kb, doublecomplex
*ab, int ldab, doublecomplex *bb, int ldbb, double  *w,  dou-
blecomplex *z, int ldz, int *info);

void  zhbgvd_64(char jobz, char uplo, long n, long ka, long kb, double-
complex *ab, long ldab, doublecomplex *bb, long ldbb,  double
*w, doublecomplex *z, long ldz, long *info);

Description

Oracle Solaris Studio Performance Library                           zhbgvd(3P)



NAME
       zhbgvd  - compute all the eigenvalues, and optionally, the eigenvectors
       of a complex generalized Hermitian-definite banded eigenproblem, of the
       form A*x=(lambda)*B*x


SYNOPSIS
       SUBROUTINE ZHBGVD(JOBZ, UPLO, N, KA, KB, AB, LDAB, BB, LDBB, W, Z,
             LDZ, WORK, LWORK, RWORK, LRWORK, IWORK, LIWORK, INFO)

       CHARACTER*1 JOBZ, UPLO
       DOUBLE COMPLEX AB(LDAB,*), BB(LDBB,*), Z(LDZ,*), WORK(*)
       INTEGER N, KA, KB, LDAB, LDBB, LDZ, LWORK, LRWORK, LIWORK, INFO
       INTEGER IWORK(*)
       DOUBLE PRECISION W(*), RWORK(*)

       SUBROUTINE ZHBGVD_64(JOBZ, UPLO, N, KA, KB, AB, LDAB, BB, LDBB, W, Z,
             LDZ, WORK, LWORK, RWORK, LRWORK, IWORK, LIWORK, INFO)

       CHARACTER*1 JOBZ, UPLO
       DOUBLE COMPLEX AB(LDAB,*), BB(LDBB,*), Z(LDZ,*), WORK(*)
       INTEGER*8 N, KA, KB, LDAB, LDBB, LDZ, LWORK, LRWORK, LIWORK, INFO
       INTEGER*8 IWORK(*)
       DOUBLE PRECISION W(*), RWORK(*)




   F95 INTERFACE
       SUBROUTINE HBGVD(JOBZ, UPLO, N, KA, KB, AB, LDAB, BB, LDBB, W,
              Z, LDZ, WORK, LWORK, RWORK, LRWORK, IWORK, LIWORK,
              INFO)

       CHARACTER(LEN=1) :: JOBZ, UPLO
       COMPLEX(8), DIMENSION(:) :: WORK
       COMPLEX(8), DIMENSION(:,:) :: AB, BB, Z
       INTEGER :: N, KA, KB, LDAB, LDBB, LDZ, LWORK, LRWORK, LIWORK, INFO
       INTEGER, DIMENSION(:) :: IWORK
       REAL(8), DIMENSION(:) :: W, RWORK

       SUBROUTINE HBGVD_64(JOBZ, UPLO, N, KA, KB, AB, LDAB, BB, LDBB,
              W, Z, LDZ, WORK, LWORK, RWORK, LRWORK, IWORK, LIWORK,
              INFO)

       CHARACTER(LEN=1) :: JOBZ, UPLO
       COMPLEX(8), DIMENSION(:) :: WORK
       COMPLEX(8), DIMENSION(:,:) :: AB, BB, Z
       INTEGER(8) :: N, KA, KB, LDAB, LDBB, LDZ, LWORK, LRWORK, LIWORK, INFO
       INTEGER(8), DIMENSION(:) :: IWORK
       REAL(8), DIMENSION(:) :: W, RWORK




   C INTERFACE
       #include <sunperf.h>

       void  zhbgvd(char jobz, char uplo, int n, int ka, int kb, doublecomplex
                 *ab, int ldab, doublecomplex *bb, int ldbb, double  *w,  dou-
                 blecomplex *z, int ldz, int *info);

       void  zhbgvd_64(char jobz, char uplo, long n, long ka, long kb, double-
                 complex *ab, long ldab, doublecomplex *bb, long ldbb,  double
                 *w, doublecomplex *z, long ldz, long *info);



PURPOSE
       zhbgvd  computes  all the eigenvalues, and optionally, the eigenvectors
       of a complex generalized Hermitian-definite banded eigenproblem, of the
       form  A*x=(lambda)*B*x.  Here  A  and B are assumed to be Hermitian and
       banded, and B is also positive definite.  If eigenvectors are  desired,
       it uses a divide and conquer algorithm.

       The  divide  and  conquer  algorithm  makes very mild assumptions about
       floating point arithmetic. It will work on machines with a guard  digit
       in add/subtract, or on those binary machines without guard digits which
       subtract like the Cray X-MP, Cray Y-MP, Cray C-90, or Cray-2. It  could
       conceivably  fail on hexadecimal or decimal machines without guard dig-
       its, but we know of none.


ARGUMENTS
       JOBZ (input)
                 = 'N':  Compute eigenvalues only;
                 = 'V':  Compute eigenvalues and eigenvectors.


       UPLO (input)
                 = 'U':  Upper triangles of A and B are stored;
                 = 'L':  Lower triangles of A and B are stored.


       N (input) The order of the matrices A and B.  N >= 0.


       KA (input)
                 The number of superdiagonals of the matrix A if UPLO  =  'U',
                 or the number of subdiagonals if UPLO = 'L'. KA >= 0.


       KB (input)
                 The  number  of superdiagonals of the matrix B if UPLO = 'U',
                 or the number of subdiagonals if UPLO = 'L'. KB >= 0.


       AB (input/output)
                 On entry, the upper or lower triangle of the  Hermitian  band
                 matrix A, stored in the first ka+1 rows of the array.  The j-
                 th column of A is stored in the j-th column of the  array  AB
                 as  follows:  if  UPLO  =  'U',  AB(ka+1+i-j,j)  = A(i,j) for
                 max(1,j-ka)<=i<=j; if UPLO = 'L', AB(1+i-j,j)    = A(i,j) for
                 j<=i<=min(n,j+ka).

                 On exit, the contents of AB are destroyed.


       LDAB (input)
                 The leading dimension of the array AB.  LDAB >= KA+1.


       BB (input/output)
                 On  entry,  the upper or lower triangle of the Hermitian band
                 matrix B, stored in the first kb+1 rows of the array.  The j-
                 th  column  of B is stored in the j-th column of the array BB
                 as follows: if  UPLO  =  'U',  BB(kb+1+i-j,j)  =  B(i,j)  for
                 max(1,j-kb)<=i<=j; if UPLO = 'L', BB(1+i-j,j)    = B(i,j) for
                 j<=i<=min(n,j+kb).

                 On exit, the factor S from the split Cholesky factorization B
                 = S**H*S, as returned by CPBSTF.


       LDBB (input)
                 The leading dimension of the array BB.  LDBB >= KB+1.


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


       Z (output)
                 If  JOBZ  = 'V', then if INFO = 0, Z contains the matrix Z of
                 eigenvectors, with the i-th column of Z holding the eigenvec-
                 tor  associated with W(i). The eigenvectors are normalized so
                 that Z**H*B*Z = 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 >= N.


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


       LWORK (input)
                 The  dimension   of   the   array   WORK.    If   N   <=   1,
                 LWORK  >= 1.  If JOBZ = 'N' and N > 1, LWORK >= N.  If JOBZ =
                 'V' and N > 1, LWORK >= 2*N**2.

                 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)
                 On exit, if INFO=0, RWORK(1) returns the optimal LRWORK.


       LRWORK (input)
                 The    dimension    of    array    RWORK.    If   N   <=   1,
                 LRWORK >= 1.  If JOBZ = 'N' and N > 1,  LRWORK  >=  2*N.   If
                 JOBZ = 'V' and N > 1, LRWORK >= 1 + 5*N + 2*N**2.

                 If  LRWORK  = -1, then a workspace query is assumed; the rou-
                 tine only calculates the optimal size  of  the  RWORK  array,
                 returns this value as the first entry of the RWORK array, and
                 no error message related to LRWORK is issued by XERBLA.


       IWORK (workspace/output)
                 On exit, if INFO=0, IWORK(1) returns the optimal LIWORK.


       LIWORK (input)
                 The dimension of array IWORK.  If JOBZ  =  'N'  or  N  <=  1,
                 LIWORK >= 1.  If JOBZ = 'V' and N > 1, LIWORK >= 3 + 5*N.

                 If  LIWORK  = -1, then a workspace query is assumed; the rou-
                 tine only calculates the optimal size  of  the  IWORK  array,
                 returns this value as the first entry of the IWORK array, and
                 no error message related to LIWORK is issued by XERBLA.


       INFO (output)
                 = 0:  successful exit
                 < 0:  if INFO = -i, the i-th argument had an illegal value
                 > 0:  if INFO = i, and i is:
                 <= N:  the algorithm failed to converge: i off-diagonal  ele-
                 ments of an intermediate tridiagonal form did not converge to
                 zero; > N:   if INFO = N + i, for 1 <= i <= N, then CPBSTF
                 returned INFO = i: B is not positive definite.   The  factor-
                 ization  of  B  could  not be completed and no eigenvalues or
                 eigenvectors were computed.

FURTHER DETAILS
       Based on contributions by
          Mark Fahey, Department of Mathematics, Univ. of Kentucky, USA




                                  7 Nov 2015                        zhbgvd(3P)