SRC/csycon_rook.f(3)

💅 SRC/csycon_rook.f — the rook one, condition-number edition

So bestie, this page is from the LAPACK Library Functions Manual, and it's literally all about csycon_rook 🎀. Buckle up.

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✨ NAME ✨

SRC/csycon_rook.f — that's the file, that's the vibe, that's the whole name section, periodt.

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🌸 SYNOPSIS 🌸

Functions/Subroutines

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

And what does it do? That's right: CSYCON_ROOK 🫶

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🦋 Function/Subroutine Documentation 🦋

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

CSYCON_ROOK — say it with me 👑

🧚 Purpose

!> !> CSYCON_ROOK estimates the reciprocal of the condition number (in the !> 1-norm) of a complex symmetric matrix A using the factorization !> A = U*D*U**T or A = L*D*L**T computed by CSYTRF_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))). !>

Translation bestie: it peeks at the factorization that CSYTRF_ROOK already did, estimates norm(inv(A)), and hands you back RCOND = 1 / (ANORM * norm(inv(A))) 💖

💀 Parameters

• UPLO — a CHARACTER*1, no cap. Tells us whether the factorization details are stored as an upper or lower triangular matrix:

!> 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**T; !> = 'L': Lower triangular, form is A = L*D*L**T. !>

• N — INTEGER, the order of the matrix A 💫 Constraint: N >= 0.

!> N is INTEGER !> The order of the matrix A. N >= 0. !>

• A — COMPLEX array, dimension (LDA,N). It's the block diagonal matrix D plus the multipliers used to get the factor U or L, exactly as computed by CSYTRF_ROOK 🌈

!> 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 CSYTRF_ROOK. !>

• LDA — INTEGER, the leading dimension of the array A. Constraint: LDA >= max(1,N) 🍓

!> LDA is INTEGER !> The leading dimension of the array A. LDA >= max(1,N). !>

• IPIV — INTEGER array, dimension (N). The tea on the interchanges and the block structure of D, as determined by CSYTRF_ROOK 🙈

!> IPIV is INTEGER array, dimension (N) !> Details of the interchanges and the block structure of D !> as determined by CSYTRF_ROOK. !>

• ANORM — REAL. The 1-norm of the original matrix A ⭐

!> ANORM is REAL !> The 1-norm of the original matrix A. !>

• RCOND — 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 right here in this very routine 💅

!> 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 — COMPLEX array, dimension (2*N) 🔥

!> WORK is COMPLEX array, dimension (2*N) !>

• INFO — INTEGER, the status check bestie:

!> INFO is INTEGER !> = 0: successful exit !> < 0: if INFO = -i, the i-th argument had an illegal value !>

👑 Author

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

🎀 Contributors

!> !> April 2012, Igor Kozachenko, !> Computer Science Division, !> University of California, Berkeley !> !> September 2007, Sven Hammarling, Nicholas J. Higham, Craig Lucas, !> School of Mathematics, !> University of Manchester !> !>

Shoutout to the whole squad honestly 🫶

Definition at line 137 of file csycon_rook.f.

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💖 Author

Generated automatically by Doxygen for LAPACK from the source code. (Not a human, just a robot doing its little thing 🤖✨)

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LAPACK — Version 3.12.0 🌟 that's the source and version, babes, and this page is SRC/csycon_rook.f(3). Go forth and estimate those condition numbers responsibly 😭💜