zgbbrd(3P) Sun Performance Library zgbbrd(3P)NAMEzgbbrd - reduce a complex general m-by-n band matrix A to real upper
bidiagonal form B by a unitary transformation
SYNOPSIS
SUBROUTINE ZGBBRD(VECT, M, N, NCC, KL, KU, AB, LDAB, D, E, Q, LDQ,
PT, LDPT, C, LDC, WORK, RWORK, INFO)
CHARACTER * 1 VECT
DOUBLE COMPLEX AB(LDAB,*), Q(LDQ,*), PT(LDPT,*), C(LDC,*), WORK(*)
INTEGER M, N, NCC, KL, KU, LDAB, LDQ, LDPT, LDC, INFO
DOUBLE PRECISION D(*), E(*), RWORK(*)
SUBROUTINE ZGBBRD_64(VECT, M, N, NCC, KL, KU, AB, LDAB, D, E, Q, LDQ,
PT, LDPT, C, LDC, WORK, RWORK, INFO)
CHARACTER * 1 VECT
DOUBLE COMPLEX AB(LDAB,*), Q(LDQ,*), PT(LDPT,*), C(LDC,*), WORK(*)
INTEGER*8 M, N, NCC, KL, KU, LDAB, LDQ, LDPT, LDC, INFO
DOUBLE PRECISION D(*), E(*), RWORK(*)
F95 INTERFACE
SUBROUTINE GBBRD(VECT, M, [N], [NCC], KL, KU, AB, [LDAB], D, E, Q,
[LDQ], PT, [LDPT], C, [LDC], [WORK], [RWORK], [INFO])
CHARACTER(LEN=1) :: VECT
COMPLEX(8), DIMENSION(:) :: WORK
COMPLEX(8), DIMENSION(:,:) :: AB, Q, PT, C
INTEGER :: M, N, NCC, KL, KU, LDAB, LDQ, LDPT, LDC, INFO
REAL(8), DIMENSION(:) :: D, E, RWORK
SUBROUTINE GBBRD_64(VECT, M, [N], [NCC], KL, KU, AB, [LDAB], D, E,
Q, [LDQ], PT, [LDPT], C, [LDC], [WORK], [RWORK], [INFO])
CHARACTER(LEN=1) :: VECT
COMPLEX(8), DIMENSION(:) :: WORK
COMPLEX(8), DIMENSION(:,:) :: AB, Q, PT, C
INTEGER(8) :: M, N, NCC, KL, KU, LDAB, LDQ, LDPT, LDC, INFO
REAL(8), DIMENSION(:) :: D, E, RWORK
C INTERFACE
#include <sunperf.h>
void zgbbrd(char vect, int m, int n, int ncc, int kl, int ku, double‐
complex *ab, int ldab, double *d, double *e, doublecomplex
*q, int ldq, doublecomplex *pt, int ldpt, doublecomplex *c,
int ldc, int *info);
void zgbbrd_64(char vect, long m, long n, long ncc, long kl, long ku,
doublecomplex *ab, long ldab, double *d, double *e, double‐
complex *q, long ldq, doublecomplex *pt, long ldpt, double‐
complex *c, long ldc, long *info);
PURPOSEzgbbrd reduces a complex general m-by-n band matrix A to real upper
bidiagonal form B by a unitary transformation: Q' * A * P = B.
The routine computes B, and optionally forms Q or P', or computes Q'*C
for a given matrix C.
ARGUMENTS
VECT (input)
Specifies whether or not the matrices Q and P' are to be
formed. = 'N': do not form Q or P';
= 'Q': form Q only;
= 'P': form P' only;
= 'B': form both.
M (input) The number of rows of the matrix A. M >= 0.
N (input) The number of columns of the matrix A. N >= 0.
NCC (input)
The number of columns of the matrix C. NCC >= 0.
KL (input)
The number of subdiagonals of the matrix A. KL >= 0.
KU (input)
The number of superdiagonals of the matrix A. KU >= 0.
AB (input/output)
On entry, the m-by-n band matrix A, stored in rows 1 to
KL+KU+1. The j-th column of A is stored in the j-th column of
the array AB as follows: AB(ku+1+i-j,j) = A(i,j) for max(1,j-
ku)<=i<=min(m,j+kl). On exit, A is overwritten by values
generated during the reduction.
LDAB (input)
The leading dimension of the array A. LDAB >= KL+KU+1.
D (output)
The diagonal elements of the bidiagonal matrix B.
E (output)
The superdiagonal elements of the bidiagonal matrix B.
Q (output)
If VECT = 'Q' or 'B', the m-by-m unitary matrix Q. If VECT =
'N' or 'P', the array Q is not referenced.
LDQ (input)
The leading dimension of the array Q. LDQ >= max(1,M) if
VECT = 'Q' or 'B'; LDQ >= 1 otherwise.
PT (output)
If VECT = 'P' or 'B', the n-by-n unitary matrix P'. If VECT
= 'N' or 'Q', the array PT is not referenced.
LDPT (input)
The leading dimension of the array PT. LDPT >= max(1,N) if
VECT = 'P' or 'B'; LDPT >= 1 otherwise.
C (input/output)
On entry, an m-by-ncc matrix C. On exit, C is overwritten by
Q'*C. C is not referenced if NCC = 0.
LDC (input)
The leading dimension of the array C. LDC >= max(1,M) if NCC
> 0; LDC >= 1 if NCC = 0.
WORK (workspace)
dimension(MAX(M,N))
RWORK (workspace)
dimension(MAX(M,N))
INFO (output)
= 0: successful exit.
< 0: if INFO = -i, the i-th argument had an illegal value.
6 Mar 2009 zgbbrd(3P)
