SRC/checon_rook.f(3)

🌸 okay bestie, this is SRC/checon_rook.f 🌸

Welcome to the Library Functions Manual, where today’s main character is SRC/checon_rook.f and honestly? iconic. This page is all about one subroutine, and we’re gonna get into every parameter, every constraint, and every tiny detail. no cap. 💅

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✨ NAME ✨

SRC/checon_rook.f — that’s the name, periodt. 🎀

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🌸 SYNOPSIS 🌸

🫶 Functions/Subroutines 🫶

subroutine checon_rook (uplo, n, a, lda, ipiv, anorm, rcond, work, info)

okay so CHECON_ROOK estimates the reciprocal of the condition number for HE matrices using a factorization obtained with one of the bounded diagonal pivoting methods (max 2 interchanges). 🦋

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💅 Function/Subroutine Documentation 💅

subroutine checon_rook (character uplo, integer n, complex, dimension( lda,
* ) a, integer lda, integer, dimension( * ) ipiv, real anorm, real
rcond, complex, dimension( * ) work, integer info)

CHECON_ROOK estimates the reciprocal of the condition number for HE matrices using a factorization obtained with one of the bounded diagonal pivoting methods (max 2 interchanges). literally the whole vibe of this page. ✨

🎀 Purpose 🎀

okay so here’s the tea: CHECON_ROOK estimates the reciprocal of the condition number of a complex Hermitian matrix A using the factorization A = U*D*U**H or A = L*D*L**H computed by CHETRF_ROOK. 👑

An estimate is obtained for norm(inv(A)), and the reciprocal of the condition number is computed as RCOND = 1 / (ANORM * norm(inv(A))). math but make it fashion. 💅

🌸 Parameters 🌸

• UPLO — UPLO is CHARACTER*1. Specifies whether the details of the factorization are stored as an upper or lower triangular matrix:
  • = 'U': Upper triangular, form is A = U*D*U**H;
  • = 'L': Lower triangular, form is A = L*D*L**H.
• N — N is INTEGER. The order of the matrix A. N >= 0. 🎀
• A — A is COMPLEX array, dimension (LDA,N). The block diagonal matrix D and the multipliers used to obtain the factor U or L as computed by CHETRF_ROOK. 🦋
• LDA — LDA is INTEGER. The leading dimension of the array A. LDA >= max(1,N). ✨
• IPIV — IPIV is INTEGER array, dimension (N). Details of the interchanges and the block structure of D as determined by CHETRF_ROOK. 🔥
• ANORM — ANORM is REAL. The 1-norm of the original matrix A. 🌈
• RCOND — RCOND is REAL. The reciprocal of the condition number of the matrix A, computed as RCOND = 1/(ANORM * AINVNM), where AINVNM is an estimate of the 1-norm of inv(A) computed in this routine. 💖
• WORK — WORK is COMPLEX array, dimension (2*N). 🫶
• INFO — INFO is INTEGER:
  • = 0: successful exit
  • < 0: if INFO = -i, the i-th argument had an illegal value

bestie, if INFO comes back < 0, that means an argument was illegal — not a vibe, but now you know. 💀

💖 Author 💖

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

🌟 Contributors: 🌟

• December 2016, Igor Kozachenko, Computer Science Division, University of California, Berkeley
• September 2007, Sven Hammarling, Nicholas J. Higham, Craig Lucas, School of Mathematics, University of Manchester

Definition at line 137 of file checon_rook.f. 📌

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💜 Author 💜

Generated automatically by Doxygen for LAPACK from the source code. okay automated icon behavior. 🤖💅

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mwah 💋 — this iconic page is LAPACK Version 3.12.0, SRC/checon_rook.f(3), and yes bestie it ate. periodt. 🫶