SGETF2(3)

🌸 SGETF2(3) — the girlies' guide to sgetf2.f 💅

okay so this one lives at /home/abui...RC/sgetf2.f(3) and it's from the Library Functions Manual, and the actual source file is /home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/sgetf2.f. bestie, we're in the LAPACK source tree and it's giving iconic Fortran. ✨

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🎀 NAME 🎀

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/sgetf2.f

like yes, that's the whole name. she's a whole path. main character energy fr.

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🦋 SYNOPSIS 🦋

Functions/Subroutines

subroutine SGETF2 (m, n, a, lda, ipiv, info)

SGETF2 computes the LU factorization of a general m-by-n matrix using partial pivoting with row interchanges (unblocked algorithm). no cap. 🔥

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👑 Function/Subroutine Documentation 👑

subroutine SGETF2 (integer m, integer n, real, dimension( lda, * ) a,
    integer lda, integer, dimension( * ) ipiv, integer info)

SGETF2 computes the LU factorization of a general m-by-n matrix using partial pivoting with row interchanges (unblocked algorithm). same queen, different section header 🫶

💖 Purpose 💖

!> !> SGETF2 computes an LU factorization of a general m-by-n matrix A !> using partial pivoting with row interchanges. !> !> The factorization has the form !> A = P * L * U !> where P is a permutation matrix, L is lower triangular with unit !> diagonal elements (lower trapezoidal if m > n), and U is upper !> triangular (upper trapezoidal if m < n). !> !> This is the right-looking Level 2 BLAS version of the algorithm. !>

so basically A = P * L * U and she's out here doing the right-looking Level 2 BLAS version of the algorithm. lowkey a legend 🧚

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✨ Parameters ✨

M

!> M is INTEGER !> The number of rows of the matrix A. M >= 0. !>

rows, bestie. how many. and M >= 0 is non-negotiable 💀

N

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

columns. also N >= 0. we respect the bounds in this house 🎀

A

!> A is REAL array, dimension (LDA,N) !> On entry, the m by n matrix to be factored. !> On exit, the factors L and U from the factorization !> A = P*L*U; the unit diagonal elements of L are not stored. !>

she goes in as your m by n matrix and comes out as the factors L and U from A = P*L*U. heads up tho — the unit diagonal elements of L are not stored. not me looking for them 😭

LDA

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

leading dimension of the array A, and it's gotta be LDA >= max(1,M). periodt.

IPIV

!> IPIV is INTEGER array, dimension (min(M,N)) !> The pivot indices; for 1 <= i <= min(M,N), row i of the !> matrix was interchanged with row IPIV(i). !>

pivot indices, dimension (min(M,N)). for 1 <= i <= min(M,N), row i of the matrix was interchanged with row IPIV(i). tracking? slay 💅

INFO

!> INFO is INTEGER !> = 0: successful exit !> < 0: if INFO = -k, the k-th argument had an illegal value !> > 0: if INFO = k, U(k,k) is exactly zero. The factorization !> has been completed, but the factor U is exactly !> singular, and division by zero will occur if it is used !> to solve a system of equations. !>

the vibe check variable, honestly:

• = 0: successful exit 🎉
• < 0: if INFO = -k, the k-th argument had an illegal value 🙈
• > 0: if INFO = k, U(k,k) is exactly zero. The factorization has been completed, but the factor U is exactly singular, and division by zero will occur if it is used to solve a system of equations. division by zero. i'm screaming 💀

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🌈 Author 🌈

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

the whole squad contributed. respect 🫶

Definition at line 107 of file sgetf2.f.

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⭐ Author ⭐

Generated automatically by Doxygen for LAPACK from the source code. (yes, a bot wrote the docs. she still ate. 🤖✨)

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ngl this is the unblocked algorithm, so keep that in mind if you were expecting something fancier — the page says unblocked and we believe her. 🦋

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kisses, bestie 💜 this page was brought to you by LAPACK, Version 3.12.0, living at /home/abui...RC/sgetf2.f(3) — go forth and factor responsibly 🍓