SSYRK/DSYRK/CHERK/CSYRK/ZHERK/ZSYRK

Rank-k update

 

ldc

The leading dimension of array c as declared in the

 

 

calling program unit, with ldc ≥ max(n,1).

 

Output

c

The upper or lower triangle of the updated C matrix, as

 

 

specified by uplo, replaces the upper or lower triangle

 

 

of the input, respectively. The other triangle of c is

 

 

unchanged.

 

Notes These subprograms conform to specifications of the Level 3 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:

uplo ≠ ’L’ or ’l’ or ’U’ or ’u’

trans ≠ ’N’ or ’n’ or ’T’ or ’t’ or ’C’ or ’c’ n < 0

k < 0

lda too small ldc < max(m,1)

Also, some values of trans listed above are invalid in subprograms CHERK, CSYRK, ZHERK, and ZSYRK.

Actual character arguments in a subroutine call can be longer than the corresponding dummy arguments. Therefore, readability of the CALL statement may be improved, for example, by coding the uplo argument as ’LOWER’ for ’L’ or ’UPPER’ for ’U’. Refer to “Example 2.”

292HP MLIB User’s Guide