HP MLIB User's Guide Vol. 1 7th Ed.

Chapter 3 Basic Matrix Operations 395
Symmetric rank-2 update F_SSYR2/F_DSYR2/F_CSYR2/F_ZSYR2
INTEGER*4 INCX, INCY, LDA, N, UPLO
COMPLEX*16 ALPHA, BETA
COMPLEX*16 A( LDA, * ), X( * ), Y( * )
SUBROUTINE F_ZSYR2 (UPLO, N, ALPHA, X, INCX, Y, INCY, BETA, A,
LDA)
VECLIB8
INTEGER*8 INCX, INCY, LDA, N, UPLO
REAL*4 ALPHA, BETA
REAL*4 A( LDA, * ), X( * ), Y( * )
SUBROUTINE F_SSYR2 (UPLO, N, ALPHA, X, INCX, Y, INCY, BETA, A,
LDA)
INTEGER*8 INCX, INCY, LDA, N, UPLO
REAL*8 ALPHA, BETA
REAL*8 A( LDA, * ), X( * ), Y( * )
SUBROUTINE F_DSYR2 (UPLO, N, ALPHA, X, INCX, Y, INCY, BETA, A,
LDA)
INTEGER*8 INCX, INCY, LDA, N, UPLO
COMPLEX*8 ALPHA, BETA
COMPLEX*8 A( LDA, * ), X( * ), Y( * )
SUBROUTINE F_CSYR2 (UPLO, N, ALPHA, X, INCX, Y, INCY, BETA, A,
LDA)
INTEGER*8 INCX, INCY, LDA, N, UPLO
COMPLEX*16 ALPHA, BETA
COMPLEX*16 A( LDA, * ), X( * ), Y( * )
SUBROUTINE F_ZSYR2 (UPLO, N, ALPHA, X, INCX, Y, INCY, BETA, A,
LDA)
Input UPLO Specifies whether a triangular matrix is upper or lower
triangular. Use either BLAS_UPPER or BLAS_LOWER.
N Number of elements of vector x.
ALPHA The scalar ALPHA.
X REAL or COMPLEX array, minimum length
(N - 1) x |incx| + 1.
INCX Increment for the array x. A vector x having component
x
i
, i = 1,..., n, is stored in an array X() with increment
argument incx. If incx > 0 then x
i
is stored in
X (1 + (i - 1) x incx). If incx < 0 then x
i
is stored in
X (1 + (N - i) x |incx|). incx = 0 is an illegal value.