Contents
sgbmv - perform one of the matrix-vector operations y :=
alpha*A*x + beta*y or y := alpha*A'*x + beta*y
SUBROUTINE SGBMV(TRANSA, M, N, KL, KU, ALPHA, A, LDA, X, INCX,
BETA, Y, INCY)
CHARACTER * 1 TRANSA
INTEGER M, N, KL, KU, LDA, INCX, INCY
REAL ALPHA, BETA
REAL A(LDA,*), X(*), Y(*)
SUBROUTINE SGBMV_64(TRANSA, M, N, KL, KU, ALPHA, A, LDA, X,
INCX, BETA, Y, INCY)
CHARACTER * 1 TRANSA
INTEGER*8 M, N, KL, KU, LDA, INCX, INCY
REAL ALPHA, BETA
REAL A(LDA,*), X(*), Y(*)
F95 INTERFACE
SUBROUTINE GBMV([TRANSA], [M], [N], KL, KU, ALPHA, A, [LDA], X,
[INCX], BETA, Y, [INCY])
CHARACTER(LEN=1) :: TRANSA
INTEGER :: M, N, KL, KU, LDA, INCX, INCY
REAL :: ALPHA, BETA
REAL, DIMENSION(:) :: X, Y
REAL, DIMENSION(:,:) :: A
SUBROUTINE GBMV_64([TRANSA], [M], [N], KL, KU, ALPHA, A, [LDA],
X, [INCX], BETA, Y, [INCY])
CHARACTER(LEN=1) :: TRANSA
INTEGER(8) :: M, N, KL, KU, LDA, INCX, INCY
REAL :: ALPHA, BETA
REAL, DIMENSION(:) :: X, Y
REAL, DIMENSION(:,:) :: A
C INTERFACE
#include <sunperf.h>
void sgbmv(char transa, int m, int n, int kl, int ku, float
alpha, float *a, int lda, float *x, int incx,
float beta, float *y, int incy);
void sgbmv_64(char transa, long m, long n, long kl, long ku,
float alpha, float *a, long lda, float *x, long
incx, float beta, float *y, long incy);
sgbmv performs one of the matrix-vector operations y :=
alpha*A*x + beta*y or y := alpha*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.
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*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 >= 0. Unchanged on exit.
N (input)
On entry, N specifies the number of columns of the
matrix A. N >= 0. Unchanged on exit.
KL (input)
On entry, KL specifies the number of sub-diagonals
of the matrix A. KL >= 0. Unchanged on exit.
KU (input)
On entry, KU specifies the number of super-
diagonals of the matrix A. KU >= 0. 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 starting 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 refer-
enced. 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 >= (
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 <> 0. Unchanged on exit.
BETA (input)
On entry, BETA specifies the scalar beta. When
BETA is supplied 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 overwrit-
ten by the updated vector y.
INCY (input)
On entry, INCY specifies the increment for the
elements of Y. INCY <> 0. Unchanged on exit.