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

Chapter 3 Basic Matrix Operations 333
Solve triangular system STRSV/DTRSV/CTRSV/ZTRSV
CHARACTER*1 uplo, trans, diag
INTEGER*4 n, lda, incx
COMPLEX*16 a(lda, n), x(lenx)
CALL ZTRSV(uplo, trans, diag, n, a, lda, x, incx)
VECLIB8:
CHARACTER*1 uplo, trans, diag
INTEGER*8 n, lda, incx
REAL*4 a(lda, n), x(lenx)
CALL STRSV(uplo, trans, diag, n, a, lda, x, incx)
CHARACTER*1 uplo, trans, diag
INTEGER*8 n, lda, incx
REAL*8 a(lda, n), x(lenx)
CALL DTRSV(uplo, trans, diag, n, a, lda, x, incx)
CHARACTER*1 uplo, trans, diag
INTEGER*8 n, lda, incx
COMPLEX*8 a(lda, n), x(lenx)
CALL CTRSV(uplo, trans, diag, n, a, lda, x, incx)
CHARACTER*1 uplo, trans, diag
INTEGER*8 n, lda, incx
COMPLEX*16 a(lda, n), x(lenx)
CALL ZTRSV(uplo, trans, diag, n, a, lda, x, incx)
Input uplo Upper/lower triangular option for A:
’L’ or ’l’ Solve lower-triangular system
(forward elimination)
’U’ or ’u’ Solve upper-triangular system (back
substitution)
The other triangle of the array a is not referenced.
trans Transposition option for A:
’N’ or ’n’ Compute x ← A
−1
x
’T’ or ’t’ Compute x ← A
−T
x
’C’ or ’c’ Compute
where A
−T
is the inverse of the transpose of A, and
is the inverse of the conjugate transpose. In the real
subprograms, ’C’ and ’c’ have the same meaning as ’T’
and ’t’.
xA
*–
x←
A
*–