SRC/ctrtri.f(3)

🎀 SRC/ctrtri.f(3) — Library Functions Manual 🎀

okay bestie, welcome to the ctrtri page from the Library Functions Manual. It’s giving Level 3 BLAS realness, and I’m gonna walk you through every single parameter like the devoted Unix bestie I am. 💖

💖 NAME 💖

SRC/ctrtri.f — yes, that’s the page name, and it’s all about the CTRTRI subroutine. No cap, that’s the whole NAME section. ✨

✨ SYNOPSIS ✨

🌸 Functions/Subroutines 🌸

       subroutine ctrtri (uplo, diag, n, a, lda, info)
           CTRTRI

🦋 Function/Subroutine Documentation 🦋

   subroutine ctrtri (character uplo, character diag, integer n, complex,
       dimension( lda, * ) a, integer lda, integer info)

CTRTRI — that’s the star of the show, bestie. 👑

🔥 Purpose 🔥

CTRTRI computes the inverse of a complex upper or lower triangular matrix A.

This is the Level 3 BLAS version of the algorithm.

🎀 Parameters 🎀

• UPLO — UPLO is CHARACTER*1. It tells us which triangle of A we’re working with: = 'U': A is upper triangular; = 'L': A is lower triangular.
• DIAG — DIAG is CHARACTER*1. It says whether the diagonal is unit or not: = 'N': A is non-unit triangular; = 'U': A is unit triangular.
• N — N is INTEGER. It’s the order of the matrix A. And the rule is N >= 0.
• A — A is COMPLEX array, dimension (LDA,N). On entry, it’s the triangular matrix A. If UPLO = 'U', the leading N-by-N upper triangular part of the array A contains the upper triangular matrix, and the strictly lower triangular part of A is not referenced. If UPLO = 'L', the leading N-by-N lower triangular part of the array A contains the lower triangular matrix, and the strictly upper triangular part of A is not referenced. If DIAG = 'U', the diagonal elements of A are also not referenced and are assumed to be 1. On exit, A holds the (triangular) inverse of the original matrix, in the same storage format. Same storage format on exit — iconic. 💅
• LDA — LDA is INTEGER. It’s the leading dimension of the array A. The rule is LDA >= max(1,N).
• INFO — INFO is INTEGER. Exit status tea: = 0: successful exit; < 0: if INFO = -i, the i-th argument had an illegal value; > 0: if INFO = i, A(i,i) is exactly zero. In that case the triangular matrix is singular and its inverse can not be computed. So yeah, singular means no inverse, bestie — not a vibe. 💀

🌈 Author 🌈

• Univ. of Tennessee
• Univ. of California Berkeley
• Univ. of Colorado Denver
• NAG Ltd.

Definition at line 108 of file ctrtri.f.

👑 Author 👑

Generated automatically by Doxygen for LAPACK from the source code.

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That’s the whole page, bestie! 💖 Footer check: LAPACK Version 3.12.0, page SRC/ctrtri.f(3) — and there’s no date listed on this footer, so I’m not inventing one. 🎀 Periodt. 🫶