sspmv
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(*)
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
#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 element 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 symmetric 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 ) respectively, 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.