SRC/dgetf2.f(3)

💅 SRC/dgetf2.f(3) — Library Functions Manual 💅

okay bestie, welcome to the SRC/dgetf2.f(3) page, straight out of the Library Functions Manual — this is the one about the unblocked LU factorization girlie and she is iconic 🫶

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🌸 NAME 🌸

SRC/dgetf2.f — no cap, that's the whole name section, she's lowkey mysterious like that ✨

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✨ SYNOPSIS ✨

🎀 Functions/Subroutines 🎀

• subroutine dgetf2 (m, n, a, lda, ipiv, info) — DGETF2 computes the LU factorization of a general m-by-n matrix using partial pivoting with row interchanges (unblocked algorithm). main character energy fr fr 👑

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💖 Function/Subroutine Documentation 💖

🦋 The signature, verbatim, don't @ me 🦋

subroutine dgetf2 (integer m, integer n, double precision, dimension( lda, *
) a, integer lda, integer, dimension( * ) ipiv, integer info)

DGETF2 computes the LU factorization of a general m-by-n matrix using partial pivoting with row interchanges (unblocked algorithm). that's the whole vibe, but let's get into the lore 💅

🌟 Purpose 🌟

so the tea is: DGETF2 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). like, geometry queen 📐✨

this is the right-looking Level 2 BLAS version of the algorithm. periodt 💀

🍓 Parameters 🍓

• M — M is INTEGER. the number of rows of the matrix A. M >= 0. absolutely no negative rows allowed bestie 🙈
• N — N is INTEGER. the number of columns of the matrix A. N >= 0. same energy 💜
• A — A is DOUBLE PRECISION 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 gets a whole glow-up in place, we love a transformation arc 🌈
• LDA — LDA is INTEGER. the leading dimension of the array A. LDA >= max(1,M). respect the leading dimension or catch these hands 💅
• 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). the receipts of every row swap, iykyk 🧾
• INFO — INFO is INTEGER:
  • = 0: successful exit 🎉 slay
  • < 0: if INFO = -k, the k-th argument had an illegal value 😭 somebody passed nonsense
  • > 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. 🚨 this is the part where you panic a little — the factor U is exactly singular, and dividing by it is gonna be a whole mess 🫠

👑 Author 👑

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

the academic royalty behind it all, we stan 🎀

Definition at line 107 of file dgetf2.f. — yes she has a canonical address, line 107, remember it 📍

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💀 Author 💀

this page was Generated automatically by Doxygen for LAPACK from the source code. so like, a robot wrote it but we gave it flavor 🤖💖

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okay that's the whole page babe, go forth and factorize responsibly ✨ and yeah — this masterpiece of a manual is LAPACK Version 3.12.0, so shoutout to version 3.12.0 for making all this possible 🫶🎀💜