Contents
sspmv - perform the matrix-vector operation y := alpha*A*x
+ beta*y
SUBROUTINE SSPMV(UPLO, N, ALPHA, A, X, INCX, BETA, Y, INCY)
CHARACTER * 1 UPLO
INTEGER N, INCX, INCY
REAL ALPHA, BETA
REAL A(*), X(*), Y(*)
SUBROUTINE SSPMV_64(UPLO, N, ALPHA, A, X, INCX, BETA, Y, INCY)
CHARACTER * 1 UPLO
INTEGER*8 N, INCX, INCY
REAL ALPHA, BETA
REAL A(*), X(*), Y(*)
F95 INTERFACE
SUBROUTINE SPMV(UPLO, N, ALPHA, A, X, [INCX], BETA, Y, [INCY])
CHARACTER(LEN=1) :: UPLO
INTEGER :: N, INCX, INCY
REAL :: ALPHA, BETA
REAL, DIMENSION(:) :: A, X, Y
SUBROUTINE SPMV_64(UPLO, N, ALPHA, A, X, [INCX], BETA, Y, [INCY])
CHARACTER(LEN=1) :: UPLO
INTEGER(8) :: N, INCX, INCY
REAL :: ALPHA, BETA
REAL, DIMENSION(:) :: A, X, Y
C INTERFACE
#include <sunperf.h>
void sspmv(char uplo, int n, float alpha, float *a, float
*x, int incx, float beta, float *y, int incy);
void sspmv_64(char uplo, long n, float alpha, float *a,
float *x, long incx, float beta, float *y, long
incy);
sspmv performs the matrix-vector operation y := alpha*A*x +
beta*y, where alpha and beta are scalars, x and y are n ele-
ment vectors and A is an n by n symmetric matrix, supplied
in packed form.
UPLO (input)
On entry, UPLO specifies whether the upper or
lower triangular part of the matrix A is supplied
in the packed array A as follows:
UPLO = 'U' or 'u' The upper triangular part of A
is supplied in A.
UPLO = 'L' or 'l' The lower triangular part of A
is supplied in A.
Unchanged on exit.
N (input)
On entry, N specifies the order of the matrix A.
N >= 0. Unchanged on exit.
ALPHA (input)
On entry, ALPHA specifies the scalar alpha.
Unchanged on exit.
A (input)
( ( n*( n + 1 ) )/2 ). Before entry with UPLO =
'U' or 'u', the array A must contain the upper
triangular part of the symmetric matrix packed
sequentially, column by column, so that A( 1 )
contains a( 1, 1 ), A( 2 ) and A( 3 ) contain a(
1, 2 ) and a( 2, 2 ) respectively, and so on.
Before entry with UPLO = 'L' or 'l', the array A
must contain the lower triangular part of the sym-
metric matrix packed sequentially, column by
column, so that A( 1 ) contains a( 1, 1 ), A( 2 )
and A( 3 ) contain a( 2, 1 ) and a( 3, 1 ) respec-
tively, and so on. Unchanged on exit.
X (input)
( 1 + ( n - 1 )*abs( INCX ) ). Before entry, the
incremented array X must contain the n element
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 + ( n - 1 )*abs( INCY ) ). Before entry, the
incremented array Y must contain the n element
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 <> 0. Unchanged on exit.