STRCON(3)

🦋 STRCON(3) — like, the condition number girly for triangular matrices 💅

okay so bestie, welcome to the Library Functions Manual entry for STRCON ✨ this whole thing lives at /home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/strcon.f and honestly? she's iconic. let's get into it 🎀

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✨ SYNOPSIS ✨

🌸 Functions/Subroutines

subroutine STRCON (norm, uplo, diag, n, a, lda, rcond, work, iwork,
    info)

STRCON — yes that's her name, that's the whole vibe 💖

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💜 Function/Subroutine Documentation 💜

subroutine STRCON (character norm, character uplo, character diag, integer
    n, real, dimension( lda, * ) a, integer lda, real rcond, real,
    dimension( * ) work, integer, dimension( * ) iwork, integer info)

STRCON 🫶 (yes, again — she contains multitudes)

🧚 Purpose:

!> STRCON estimates the reciprocal of the condition number of a !> triangular matrix A, in either the 1-norm or the infinity-norm. !> !> The norm of A is computed and an estimate is obtained for !> norm(inv(A)), then the reciprocal of the condition number is !> computed as !> RCOND = 1 / ( norm(A) * norm(inv(A)) ). !>

so basically: she vibes out the norm of A, gets an estimate for norm(inv(A)), and then serves you the reciprocal condition number like the main character she is 👑

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🌈 Parameters

⭐ NORM

!> NORM is CHARACTER*1 !> Specifies whether the 1-norm condition number or the !> infinity-norm condition number is required: !> = '1' or 'O': 1-norm; !> = 'I': Infinity-norm. !>

pick your fighter: '1' or 'O' for the 1-norm, 'I' for the infinity-norm. that's the whole menu, no cap 💅

⭐ UPLO

!> UPLO is CHARACTER*1 !> = 'U': A is upper triangular; !> = 'L': A is lower triangular. !>

upper or lower, bestie — 'U' or 'L', choose wisely 🦋

⭐ DIAG

!> DIAG is CHARACTER*1 !> = 'N': A is non-unit triangular; !> = 'U': A is unit triangular. !>

'N' means non-unit, 'U' means unit. tiny letters, big consequences 🎀

⭐ N

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

the order of the matrix A, and yeah N >= 0 fr fr — negative N is not it 🙈

⭐ A

!> A is REAL array, dimension (LDA,N) !> 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. !>

so this is THE matrix 💖 she's a REAL array, dimension (LDA,N). if UPLO = 'U', the leading N-by-N upper triangular part holds the upper triangular matrix and the strictly lower triangular part is not referenced (like, ignored entirely, she doesn't even look at it 🙈). if UPLO = 'L', it's flipped: leading N-by-N lower triangular part is the matrix, strictly upper triangular part is not referenced. and if DIAG = 'U', the diagonal elements are also not referenced and are assumed to be 1 — so those diagonal girlies are off the clock 🎀

⭐ LDA

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

the leading dimension of the array A, and it's gotta satisfy LDA >= max(1,N) — no exceptions bestie ⭐

⭐ RCOND

!> RCOND is REAL !> The reciprocal of the condition number of the matrix A, !> computed as RCOND = 1/(norm(A) * norm(inv(A))). !>

the star of the show 🌟 she's REAL, and she's the reciprocal of the condition number of A, computed as RCOND = 1/(norm(A) * norm(inv(A))). obsessed.

⭐ WORK

!> WORK is REAL array, dimension (3*N) !>

REAL array, dimension (3*N) — three whole N's of workspace, she needs room to think 💭

⭐ IWORK

!> IWORK is INTEGER array, dimension (N) !>

INTEGER array, dimension (N) — the integer bestie 🫶

⭐ INFO

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

• = 0 — successful exit, we love a happy ending 🌸
• < 0 — uh oh, if INFO = -i, the i-th argument had an illegal value 💀

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👑 Author

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

look at the whole squad, legends only 🔥

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💫 Definition at line 135 of file strcon.f.

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🍓 Author (again, yes really)

Generated automatically by Doxygen for LAPACK from the source code.

like, she wrote herself. queen behavior 👑

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okay that's the whole page bestie, you ate 💅✨ and just so we're official: LAPACK, Version 3.12.0, dated /home/abui...RC/strcon.f(3) — mwah, mwah, bye 🫶💖🎀