/home/abui...con_rook.f(3)

✨ SSYCON_ROOK ✨

okay bestie, so this is the manual page for /home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/ssycon_rook.f — like, that whole entire path is the NAME, no cap. It's part of the LAPACK Library Functions Manual and honestly? iconic. 💅

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🌸 SYNOPSIS 🌸

Functions/Subroutines

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

SSYCON_ROOK 🫶 (yes that's the whole subtitle, she's mysterious like that)

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🦋 Function/Subroutine Documentation 🦋

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

SSYCON_ROOK ⭐

🎀 Purpose 🎀

!> !> SSYCON_ROOK estimates the reciprocal of the condition number (in the !> 1-norm) of a real symmetric matrix A using the factorization !> A = U*D*UT or A = L*D*LT computed by SSYTRF_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))). !>

So basically she's out here vibing with a real symmetric matrix A, working off the factorization A = U*D*U**T or A = L*D*L**T that SSYTRF_ROOK already handed over. She estimates norm(inv(A)) and then hits you with RCOND = 1 / (ANORM * norm(inv(A))). math slay 💖

🌈 Parameters 🌈

• UPLO — UPLO is CHARACTER*1. Tells you whether the factorization details are stored as an upper or lower triangular matrix, bestie:
  • = 'U': Upper triangular, form is A = U*D*U**T;
  • = 'L': Lower triangular, form is A = L*D*L**T.
• N — N is INTEGER. The order of the matrix A. N >= 0. (yes queen, zero is valid, she's inclusive ✨)
• A — A is REAL array, dimension (LDA,N). This is the block diagonal matrix D plus the multipliers used to obtain the factor U or L, exactly as computed by SSYTRF_ROOK. like she did NOT compute those herself, give credit where it's due 💅
• LDA — LDA is INTEGER. The leading dimension of the array A. LDA >= max(1,N). respect the bounds fr fr.
• IPIV — IPIV is INTEGER array, dimension (N). All the details of the interchanges and the block structure of D, as determined by SSYTRF_ROOK. yep, again, SSYTRF_ROOK did the work.
• ANORM — ANORM is REAL. The 1-norm of the original matrix A. she needs the original, not the factored one, okay?
• 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 REAL array, dimension (2*N). that's TWO times N, don't skimp.
• IWORK — IWORK is INTEGER array, dimension (N). integers only, no decimals allowed 🙈
• INFO — INFO is INTEGER:
  • = 0: successful exit
  • < 0: if INFO = -i, the i-th argument had an illegal value

lowkey important: if INFO comes back negative, like INFO = -i? that means the i-th argument had an illegal value. check your args bestie 😭

👑 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 !> !> !>

(shoutout to everyone who touched this file, we see you 🫶)

⭐ Definition ⭐

Definition at line 142 of file ssycon_rook.f. that's the exact spot, go look, iykyk.

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💖 Sign-off 💖

Generated automatically by Doxygen for LAPACK from the source code — like, the robots wrote the docs, we just made them cute. And this glorious page is from LAPACK Version 3.12.0, footer file /home/abui...con_rook.f(3). bye bestie, go estimate some condition numbers, periodt 💅✨🦋