SGER/DGER/CGERC/CGERU/ZGERC/ZGERU

Rank-1 update

Notes These subprograms conform to specifications of the Level 2 BLAS.

If an error in the arguments is detected, the subprograms call error handler XERBLA, which writes an error message onto the standard error file and terminates execution. The standard version of XERBLA (refer to the end of this chapter) can be replaced with a user-supplied version to change the error procedure. Error conditions are

m < 0 n < 0

lda < max(m,1) incx = 0

incy = 0

Example 1 Apply a REAL*4 rank-1 update xyT to A, where A is a 6-by-9 real matrix stored in an array A whose dimensions are 10-by-10, x is a real vector 6 elements long stored in an array X of dimension 10, and y is a real vector 9 elements long stored in an array Y, also of dimension 10.

INTEGER*4

M,N,LDA,INCX,INCY

REAL*4

ALPHA,A(10,10),X(10),Y(10)

M =

6

 

N =

9

 

ALPHA = 1.0

LDA = 10

INCX = 1

INCY = 1

CALL SGER (M,N,ALPHA,X,INCX,Y,INCY,A,LDA)

Example 2 Apply a COMPLEX*8 conjugated rank-1 update −2xy* to A, where A is a 6-by-9 complex matrix stored in an array A whose dimensions are 10 by 10, x is a complex vector 6 elements long stored in an array X of dimension 10, and y is a complex vector 9 elements long stored in an array Y, also of dimension 10.

INTEGER*4 M,N,LDA

COMPLEX*8 A(10,10),X(10),Y(10)

M = 6

N = 9

LDA = 10

CALL CGERC (M,N,(-2.0E0,0.0E0),X,1,Y,1,A,LDA)

240HP MLIB User’s Guide