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

316 HP MLIB User’s Guide
STPSV/DTPSV/CTPSV/ZTPSV Solve triangular system
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’.
diag Specifies whether the matrix is unit triangular, that is,
a
ii
= 1, or not:
’N’ or ’n’ The diagonal of A is stored in the
array
’U’ or ’u’ The diagonal of A consists of unstored
ones
When diag is supplied as ’U’ or ’u’, the diagonal
elements are not referenced.
n Number of rows and columns in matrix A, n ≥ 0. If
n = 0, the subprograms do not reference ap or x.
ap Array of length lenap = n×(n+1)/2 containing the
n-by-n triangular matrix A, stored by columns in the
packed form described above. Space must be left for the
diagonal elements of A even when diag is supplied as
’U’ or ’u’.
x Array of length lenx = (n−1)×|incx|+1 containing the
right-hand-side n-vector x.
incx Increment for the array x, incx ≠ 0:
incx > 0 x is stored forward in array x; that is,
x
i
is stored in x((i−1)×incx+1)
incx < 0 x is stored backward in array x; that
is, x
i
is stored in x((i−n)×incx+1)
Use incx = 1 if the vector x is stored contiguously in
array x, that is, if x
i
is stored in x(i). Refer to “BLAS
Indexing Conventions” in the introduction to
Chapter 2.
Output x The solution vector of the triangular system replaces
the input.
x ← A
-*
x
A
*–