BLAS/SRC/ctrsv.f(3)

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version 3.12.1 · 4 versions
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✨ NAME ✨

okay so this page is BLAS/SRC/ctrsv.f — the manual name folded up top is BLAS/SRC/ctrsv.f(3) — and it’s all about the CTRSV routine. bestie, we’re in BLAS land 💅

🌸 SYNOPSIS 🌸

🫶 Functions/Subroutines 🫶

subroutine ctrsv (uplo, trans, diag, n, a, lda, x, incx)
    CTRSV

🎀 Function/Subroutine Documentation 🎀

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

💖 Purpose 💖

CTRSV solves one of these systems of equations, no cap:

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. fr fr, do not skip that vibe check 😭

🌈 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 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 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.

🔥 INCX

INCX is INTEGER.

On entry, INCX specifies the increment for the elements of X. INCX must not be 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.

Definition at line 148 of file ctrsv.f.

✨ Author ✨

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bye bestie 💖 — this page is LAPACK Version 3.12.0, from BLAS/SRC/ctrsv.f(3) 🎀

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