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

330 HP MLIB User’s Guide
STRSM/DTRSM/CTRSM/ZTRSM Solve triangular systems
a Array whose upper or lower triangle, as specified by
uplo, contains the upper- or lower-triangular matrix A,
whose size is indicated by side:
’L’ or ’l’ A is m-by-m
’R’ or ’r’ A is n-by-n
The other triangle of a is not referenced. Not used as
input if alpha = 0.
lda The leading dimension of array a as declared in the
calling program unit, with lda ≥ max (the number of
rows of A,1).
b Array containing the m-by-n matrix B. Not used as
input if alpha = 0.
ldb The leading dimension of array b as declared in the
calling program unit, with ldb ≥ max(m,1).
Output b The indicated matrix solution replaces the input.
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:
side ≠ ’L’ or ’l’ or ’R’ or ’r’
uplo ≠ ’L’ or ’l’ or ’U’ or ’u’
transa ≠ ’N’ or ’n’ or ’T’ or ’t’ or ’C’ or ’c’
diag ≠ ’N’ or ’n’ or ’U’ or ’u’
m < 0
n < 0
lda too small
ldb < max(m,1)
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 transa argument as
’NORMAL’ or ’NONTRANS’ for ’N’, ’TRANSPOSE’ for ’T’, or ’CTRANS’ for ’C’.
Refer to “Example 2.”