BLAS/SRC/ztrsv.f(3)

📦
version 3.12.1 · 4 versions
, in arch rolling

💜 BLAS/SRC/ztrsv.f — like, the whole manual, bestie

okay so this is the man page for BLAS/SRC/ztrsv.f (that's the file it lives in, iykyk) and honestly? it's giving "small routine, big main character energy." pull up a chair 🎀

✨ SYNOPSIS ✨

Functions/Subroutines

  • subroutine ztrsv (uplo, trans, diag, n, a, lda, x, incx) — literally just ZTRSV, that's the whole vibe

🦋 Function/Subroutine Documentation 🦋

subroutine ztrsv (character uplo, character trans, character diag, integer n, complex*16, dimension(lda,*) a, integer lda, complex*16, dimension(*) x, integer incx)

ZTRSV — bestie, that's the name, that's the function 💅

🌸 Purpose:

!>
!> ZTRSV  solves one of the systems of equations
!>
!>    A*x = b,   or   A**T*x = b,   or   A**H*x = b,
!>
!> where b and x are n element vectors and A is an n by n unit, or
!> non-unit, upper or lower triangular matrix.
!>
!> No test for singularity or near-singularity is included in this
!> routine. Such tests must be performed before calling this routine.
!>

so like, ztrsv solves one of these systems of equations:

A*x = b,   or   A**T*x = b,   or   A**H*x = b,

where b and x are n element vectors and A is an n by n unit, or non-unit, upper or lower triangular matrix. slay 💖

⚠️ okay this is the important part, do NOT skip it: no test for singularity or near-singularity is included in this routine. such tests must be performed before calling this routine. fr fr, it will not vibe check your matrix for you 😭

💫 Parameters

  • UPLO — UPLO is CHARACTER*1. on entry, UPLO specifies whether the matrix is an upper or lower triangular matrix, as follows:
UPLO = 'U' or 'u'   A is an upper triangular matrix.

UPLO = 'L' or 'l'   A is a lower triangular matrix.
  • TRANS — TRANS is CHARACTER*1. on entry, TRANS specifies the equations to be solved, as follows:
TRANS = 'N' or 'n'   A*x = b.

TRANS = 'T' or 't'   A**T*x = b.

TRANS = 'C' or 'c'   A**H*x = b.
  • DIAG — DIAG is CHARACTER*1. on entry, DIAG specifies whether or not A is unit triangular, as follows:
DIAG = 'U' or 'u'   A is assumed to be unit triangular.

DIAG = 'N' or 'n'   A is not assumed to be unit
                    triangular.
  • N — N is INTEGER. on entry, N specifies the order of the matrix A. N must be at least zero.
  • A — A is COMPLEX*16 array, dimension ( LDA, N ). before entry with UPLO = 'U' or 'u', the leading n by n upper triangular part of the array A must contain the upper triangular matrix and the strictly lower triangular part of A is not referenced. before entry with UPLO = 'L' or 'l', the leading n by n lower triangular part of the array A must contain the lower triangular matrix and the strictly upper triangular part of A is not referenced. note that when DIAG = 'U' or 'u', the diagonal elements of A are not referenced either, but are assumed to be unity. 🫶
  • LDA — LDA is INTEGER. on entry, LDA specifies the first dimension of A as declared in the calling (sub) program. LDA must be at least max( 1, n ).
  • X — X is COMPLEX*16 array, dimension at least ( 1 + ( n - 1 )*abs( INCX ) ). before entry, the incremented array X must contain the n element right-hand side vector b. on exit, X is overwritten with the solution vector x. 🦋 (glow-up: b goes in, x comes out, iconic)
  • INCX — INCX is INTEGER. on entry, INCX specifies the increment for the elements of X. INCX must not be zero. 💀 like, seriously, not zero.

👑 Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

🌈 Further Details:

!>
!>  Level 2 Blas routine.
!>
!>  -- Written on 22-October-1986.
!>     Jack Dongarra, Argonne National Lab.
!>     Jeremy Du Croz, Nag Central Office.
!>     Sven Hammarling, Nag Central Office.
!>     Richard Hanson, Sandia National Labs.
!>

it's a Level 2 Blas routine ⭐ — written on 22-October-1986 by Jack Dongarra (Argonne National Lab), Jeremy Du Croz (Nag Central Office), Sven Hammarling (Nag Central Office) and Richard Hanson (Sandia National Labs). literal legends, no cap 🔥

Definition at line 148 of file ztrsv.f.

🍓 Author

Generated automatically by Doxygen for LAPACK from the source code. (yes bestie, the man page has two Author sections, and we keep both, we don't erase herstory 💅)

kisses and triangular matrices, mwah 💋 — this little love letter is from LAPACK, Version 3.12.0, dated BLAS/SRC/ztrsv.f(3), and that's the whole page, periodt 🎀✨

📦 where this page comes from