cgbmv(3P) Sun Performance Library cgbmv(3P)NAMEcgbmv - perform one of the matrix-vector operations y := alpha*A*x +
beta*y, or y := alpha*A'*x + beta*y, or y := alpha*conjg( A' )*x +
beta*y
SYNOPSIS
SUBROUTINE CGBMV(TRANSA, M, N, KL, KU, ALPHA, A, LDA, X, INCX,
BETA, Y, INCY)
CHARACTER * 1 TRANSA
COMPLEX ALPHA, BETA
COMPLEX A(LDA,*), X(*), Y(*)
INTEGER M, N, KL, KU, LDA, INCX, INCY
SUBROUTINE CGBMV_64(TRANSA, M, N, KL, KU, ALPHA, A, LDA, X,
INCX, BETA, Y, INCY)
CHARACTER * 1 TRANSA
COMPLEX ALPHA, BETA
COMPLEX A(LDA,*), X(*), Y(*)
INTEGER*8 M, N, KL, KU, LDA, INCX, INCY
F95 INTERFACE
SUBROUTINE GBMV([TRANSA], [M], [N], KL, KU, ALPHA, A, [LDA], X,
[INCX], BETA, Y, [INCY])
CHARACTER(LEN=1) :: TRANSA
COMPLEX :: ALPHA, BETA
COMPLEX, DIMENSION(:) :: X, Y
COMPLEX, DIMENSION(:,:) :: A
INTEGER :: M, N, KL, KU, LDA, INCX, INCY
SUBROUTINE GBMV_64([TRANSA], [M], [N], KL, KU, ALPHA, A, [LDA],
X, [INCX], BETA, Y, [INCY])
CHARACTER(LEN=1) :: TRANSA
COMPLEX :: ALPHA, BETA
COMPLEX, DIMENSION(:) :: X, Y
COMPLEX, DIMENSION(:,:) :: A
INTEGER(8) :: M, N, KL, KU, LDA, INCX, INCY
C INTERFACE
#include <sunperf.h>
void cgbmv(char transa, int m, int n, int kl, int ku, complex *alpha,
complex *a, int lda, complex *x, int incx, complex *beta,
complex *y, int incy);
void cgbmv_64(char transa, long m, long n, long kl, long ku, complex
*alpha, complex *a, long lda, complex *x, long incx, complex
*beta, complex *y, long incy);
PURPOSEcgbmv performs one of the matrix-vector operations y := alpha*A*x +
beta*y, or y := alpha*A'*x + beta*y, or y := alpha*conjg( A' )*x +
beta*y where alpha and beta are scalars, x and y are vectors and A is
an m by n band matrix, with kl sub-diagonals and ku super-diagonals.
ARGUMENTS
TRANSA (input)
On entry, TRANSA specifies the operation to be performed as
follows:
TRANSA = 'N' or 'n' y := alpha*A*x + beta*y.
TRANSA = 'T' or 't' y := alpha*A'*x + beta*y.
TRANSA = 'C' or 'c' y := alpha*conjg( A' )*x + beta*y.
Unchanged on exit.
TRANSA is defaulted to 'N' for F95 INTERFACE.
M (input)
On entry, M specifies the number of rows of the matrix A. M
must be at least zero. Unchanged on exit.
N (input)
On entry, N specifies the number of columns of the matrix A.
N must be at least zero. Unchanged on exit.
KL (input)
On entry, KL specifies the number of sub-diagonals of the
matrix A. KL must satisfy 0 .le. KL. Unchanged on exit.
KU (input)
On entry, KU specifies the number of super-diagonals of the
matrix A. KU must satisfy 0 .le. KU. Unchanged on exit.
ALPHA (input)
On entry, ALPHA specifies the scalar alpha. Unchanged on
exit.
A (input)
Before entry, the leading ( kl + ku + 1 ) by n part of the
array A must contain the matrix of coefficients, supplied
column by column, with the leading diagonal of the matrix in
row ( ku + 1 ) of the array, the first super-diagonal start‐
ing at position 2 in row ku, the first sub-diagonal starting
at position 1 in row ( ku + 2 ), and so on. Elements in the
array A that do not correspond to elements in the band matrix
(such as the top left ku by ku triangle) are not referenced.
The following program segment will transfer a band matrix
from conventional full matrix storage to band storage:
DO 20, J = 1, N
K = KU + 1 - J
DO 10, I = MAX( 1, J - KU ), MIN( M, J + KL )
A( K + I, J ) = matrix( I, J )
10 CONTINUE
20 CONTINUE
Unchanged on exit.
LDA (input)
On entry, LDA specifies the first dimension of A as declared
in the calling (sub) program. LDA must be at least ( kl + ku
+ 1 ). Unchanged on exit.
X (input)
( 1 + ( n - 1 )*abs( INCX ) ) when TRANSA = 'N' or 'n' and at
least ( 1 + ( m - 1 )*abs( INCX ) ) otherwise. Before entry,
the incremented array X must contain the vector x. Unchanged
on exit.
INCX (input)
On entry, INCX specifies the increment for the elements of X.
INCX must not be zero. Unchanged on exit.
BETA (input)
On entry, BETA specifies the scalar beta. When BETA is sup‐
plied as zero then Y need not be set on input. Unchanged on
exit.
Y (input/output)
( 1 + ( m - 1 )*abs( INCY ) ) when TRANSA = 'N' or 'n' and at
least ( 1 + ( n - 1 )*abs( INCY ) ) otherwise. Before entry,
the incremented array Y must contain the vector y. On exit, Y
is overwritten by the updated vector y.
INCY (input)
On entry, INCY specifies the increment for the elements of Y.
INCY must not be zero. Unchanged on exit.
6 Mar 2009 cgbmv(3P)
