Contents
cgbbrd - reduce a complex general m-by-n band matrix A to
real upper bidiagonal form B by a unitary transformation
SUBROUTINE CGBBRD(VECT, M, N, NCC, KL, KU, AB, LDAB, D, E, Q, LDQ,
PT, LDPT, C, LDC, WORK, RWORK, INFO)
CHARACTER * 1 VECT
COMPLEX AB(LDAB,*), Q(LDQ,*), PT(LDPT,*), C(LDC,*), WORK(*)
INTEGER M, N, NCC, KL, KU, LDAB, LDQ, LDPT, LDC, INFO
REAL D(*), E(*), RWORK(*)
SUBROUTINE CGBBRD_64(VECT, M, N, NCC, KL, KU, AB, LDAB, D, E, Q, LDQ,
PT, LDPT, C, LDC, WORK, RWORK, INFO)
CHARACTER * 1 VECT
COMPLEX AB(LDAB,*), Q(LDQ,*), PT(LDPT,*), C(LDC,*), WORK(*)
INTEGER*8 M, N, NCC, KL, KU, LDAB, LDQ, LDPT, LDC, INFO
REAL 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, DIMENSION(:) :: WORK
COMPLEX, DIMENSION(:,:) :: AB, Q, PT, C
INTEGER :: M, N, NCC, KL, KU, LDAB, LDQ, LDPT, LDC, INFO
REAL, 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, DIMENSION(:) :: WORK
COMPLEX, DIMENSION(:,:) :: AB, Q, PT, C
INTEGER(8) :: M, N, NCC, KL, KU, LDAB, LDQ, LDPT, LDC, INFO
REAL, DIMENSION(:) :: D, E, RWORK
C INTERFACE
#include <sunperf.h>
void cgbbrd(char vect, int m, int n, int ncc, int kl, int
ku, complex *ab, int ldab, float *d, float *e,
complex *q, int ldq, complex *pt, int ldpt, com-
plex *c, int ldc, int *info);
void cgbbrd_64(char vect, long m, long n, long ncc, long kl,
long ku, complex *ab, long ldab, float *d, float
*e, complex *q, long ldq, complex *pt, long ldpt,
complex *c, long ldc, long *info);
cgbbrd 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.
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 refer-
enced.
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 other-
wise.
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 ille-
gal value.