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

Chapter 3 Basic Matrix Operations 283
Rank-2 update SSYR2/DSYR2/CHER2/ZHER2
Example 2 Apply a COMPLEX*8 Hermitian rank-2 update to A, where A is a
9-by-9 complex Hermitian matrix whose lower triangle is stored in the lower
triangle of an array A whose dimensions are 10-by-10, α is a complex scalar, x is
a complex vector 9 elements long stored in an array X of dimension 10, and y is
a complex vector 9 elements long stored in an array Y of dimension 10.
INTEGER*4 N,LDA
COMPLEX*8 ALPHA,A(10,10),X(10),Y(10)
N = 9
LDA = 10
CALL CHER2 (’LOWER’,N,ALPHA,X,1,Y,1,A,LDA)
αxy*+αyx*