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

Chapter 3 Basic Matrix Operations 417
Triangular solve F_STRSV/F_DTRSV/F_CTRSV/F_ZTRSV
Name F_STRSV/F_DTRSV/F_CTRSV/F_ZTRSV
Triangular solve
Purpose F_xTRSV solves one of the following equations:
where x is a vector and the matrix T is a unit, non-unit, upper, or lower
triangular matrix. T
−T
is the inverse of the transpose of T, and is the
inverse of the conjugate transpose of T.
Refer to “STRSV/DTRSV/CTRSV/ZTRSV” on page 332 for a description of the
equivalent HP MLIB legacy BLAS subprograms.
Matrix
Storage
For these subprograms, you supply A in a two-dimensional array large enough
to hold a square matrix. The other triangle of the array is not referenced. If A
has an unstored unit diagonal (see input argument DIAG), then the diagonal
elements of the array also are not referenced.
Usage VECLIB
INTEGER*4 DIAG, INCX, N, TRANS, UPLO
REAL*4 ALPHA, A( LDA, * ), X( * )
SUBROUTINE F_STRSV (UPLO, TRANS, DIAG, N, ALPHA, A, LDA, X,
INCX)
INTEGER*4 DIAG, INCX, N, TRANS, UPLO
REAL*8 ALPHA, A( LDA, * ), X( * )
SUBROUTINE F_DTRSV (UPLO, TRANS, DIAG, N, ALPHA, A, LDA, X,
INCX)
INTEGER*4 DIAG, INCX, N, TRANS, UPLO
COMPLEX*8 ALPHA, A( LDA, * ), X( * )
SUBROUTINE F_CTRSV (UPLO, TRANS, DIAG, N, ALPHA, A, LDA, X,
INCX)
INTEGER*4 DIAG, INCX, N, TRANS, UPLO
COMPLEX*16 ALPHA, A( LDA, * ), X( * )
SUBROUTINE F_ZTRSV (UPLO, TRANS, DIAG, N, ALPHA, A, LDA, X,
INCX)
VECLIB8
x αT
1–
x←
x αT
T–
x←
x αT
*–
x←
T
*–