chbmv(3P) Sun Performance Library chbmv(3P)NAMEchbmv - perform the matrix-vector operation y := alpha*A*x + beta*y
SYNOPSIS
SUBROUTINE CHBMV(UPLO, N, K, ALPHA, A, LDA, X, INCX, BETA, Y,
INCY)
CHARACTER * 1 UPLO
COMPLEX ALPHA, BETA
COMPLEX A(LDA,*), X(*), Y(*)
INTEGER N, K, LDA, INCX, INCY
SUBROUTINE CHBMV_64(UPLO, N, K, ALPHA, A, LDA, X, INCX, BETA, Y,
INCY)
CHARACTER * 1 UPLO
COMPLEX ALPHA, BETA
COMPLEX A(LDA,*), X(*), Y(*)
INTEGER*8 N, K, LDA, INCX, INCY
F95 INTERFACE
SUBROUTINE HBMV(UPLO, [N], K, ALPHA, A, [LDA], X, [INCX], BETA,
Y, [INCY])
CHARACTER(LEN=1) :: UPLO
COMPLEX :: ALPHA, BETA
COMPLEX, DIMENSION(:) :: X, Y
COMPLEX, DIMENSION(:,:) :: A
INTEGER :: N, K, LDA, INCX, INCY
SUBROUTINE HBMV_64(UPLO, [N], K, ALPHA, A, [LDA], X, [INCX],
BETA, Y, [INCY])
CHARACTER(LEN=1) :: UPLO
COMPLEX :: ALPHA, BETA
COMPLEX, DIMENSION(:) :: X, Y
COMPLEX, DIMENSION(:,:) :: A
INTEGER(8) :: N, K, LDA, INCX, INCY
C INTERFACE
#include <sunperf.h>
void chbmv(char uplo, int n, int k, complex *alpha, complex *a, int
lda, complex *x, int incx, complex *beta, complex *y, int
incy);
void chbmv_64(char uplo, long n, long k, complex *alpha, complex *a,
long lda, complex *x, long incx, complex *beta, complex *y,
long incy);
PURPOSEchbmv performs the matrix-vector operation y := alpha*A*x + beta*y
where alpha and beta are scalars, x and y are n element vectors and A
is an n by n hermitian band matrix, with k super-diagonals.
ARGUMENTS
UPLO (input)
On entry, UPLO specifies whether the upper or lower triangu‐
lar part of the band matrix A is being supplied as follows:
UPLO = 'U' or 'u' The upper triangular part of A is being
supplied.
UPLO = 'L' or 'l' The lower triangular part of A is being
supplied.
Unchanged on exit.
N (input)
On entry, N specifies the order of the matrix A. N >= 0.
Unchanged on exit.
K (input)
On entry, K specifies the number of super-diagonals of the
matrix A. K must satisfy 0 .le. K. Unchanged on exit.
ALPHA (input)
On entry, ALPHA specifies the scalar alpha. Unchanged on
exit.
A (input)
Before entry with UPLO = 'U' or 'u', the leading ( k + 1 ) by
n part of the array A must contain the upper triangular band
part of the hermitian matrix, supplied column by column, with
the leading diagonal of the matrix in row ( k + 1 ) of the
array, the first super-diagonal starting at position 2 in row
k, and so on. The top left k by k triangle of the array A is
not referenced. The following program segment will transfer
the upper triangular part of a hermitian band matrix from
conventional full matrix storage to band storage:
DO 20, J = 1, N
M = K + 1 - J
DO 10, I = MAX( 1, J - K ), J
A( M + I, J ) = matrix( I, J )
10 CONTINUE
20 CONTINUE
Before entry with UPLO = 'L' or 'l', the leading ( k + 1 ) by
n part of the array A must contain the lower triangular band
part of the hermitian matrix, supplied column by column, with
the leading diagonal of the matrix in row 1 of the array, the
first sub-diagonal starting at position 1 in row 2, and so
on. The bottom right k by k triangle of the array A is not
referenced. The following program segment will transfer the
lower triangular part of a hermitian band matrix from conven‐
tional full matrix storage to band storage:
DO 20, J = 1, N
M = 1 - J
DO 10, I = J, MIN( N, J + K )
A( M + I, J ) = matrix( I, J )
10 CONTINUE
20 CONTINUE
Note that the imaginary parts of the diagonal elements need
not be set and are assumed to be zero. Unchanged on exit.
LDA (input)
On entry, LDA specifies the first dimension of A as declared
in the calling (sub) program. LDA >= ( k + 1 ). Unchanged on
exit.
X (input)
( 1 + ( n - 1 )*abs( INCX ) ). 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. Unchanged on exit.
Y (input/output)
( 1 + ( n - 1 )*abs( INCY ) ). 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 chbmv(3P)
