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

392 HP MLIB User’s Guide
F_SSYR/F_DSYR/F_CSYR/F_ZSYR Symmetric rank-1 update
Name F_SSYR/F_DSYR/F_CSYR/F_ZSYR
Symmetric rank-1 update
Purpose F_xSYR performs the symmetric rank-1 update
where A is an n-by-n real symmetric matrix, α and β are real or complex
scalars, x is a real or complex n-vector, and x
T
is the transpose of x. The routine
returns immediately if n is less than or equal to zero.
This F_xSYR interface encompasses the legacy BLAS routine SSYR with added
functionality for complex symmetric matrices. Refer to
“SSYR/DSYR/CHER/ZHER” on page 275 for a description of the equivalent HP
MLIB legacy BLAS subprograms.
Matrix
Storage
Because either triangle of A can be obtained from the other, these subprograms
reference and apply the update to only one triangle of A. You can supply either
the upper or the lower triangle of A, in a two-dimensional array large enough to
hold the entire matrix, and the same triangle of the updated matrix is returned
in the array. The other triangle of the array is not referenced.
Usage VECLIB
INTEGER*4 INCX, LDA, N, UPLO
REAL*4 ALPHA, BETA
REAL*4 A( LDA, * ), X( * )
SUBROUTINE F_SSYR (UPLO, N, ALPHA, X, INCX, BETA, A, LDA)
INTEGER*4 INCX, LDA, N, UPLO
REAL*8 ALPHA, BETA
REAL*8 A( LDA, * ), X( * )
SUBROUTINE F_DSYR (UPLO, N, ALPHA, X, INCX, BETA, A, LDA)
INTEGER*4 INCX, LDA, N, UPLO
COMPLEX*8 ALPHA, BETA
COMPLEX*8 A( LDA, * ), X( * )
SUBROUTINE F_CSYR (UPLO, N, ALPHA, X, INCX, BETA, A, LDA)
INTEGER*4 INCX, LDA, N, UPLO
COMPLEX*16 ALPHA, BETA
COMPLEX*16 A( LDA, * ), X( * )
SUBROUTINE F_ZSYR (UPLO, N, ALPHA, X, INCX, BETA, A, LDA)
VECLIB8
A αxx
T
βA with A=A
T
+←