ZGETF2(3)

💖 ZGETF2(3) — unblocked LU factorization, bestie edition ✨

okay so this page lives in the Library Functions Manual, and it's the ZGETF2(3) page. The whole vibe: LU factorization of a general m-by-n matrix with partial pivoting and row interchanges, unblocked algorithm edition. It's giving right-looking Level 2 BLAS energy 💅

🎀 NAME 🎀

The NAME here is literally the source file path, fr:

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/zgetf2.f

✨ SYNOPSIS ✨

Functions/Subroutines

subroutine ZGETF2 (m, n, a, lda, ipiv, info)

ZGETF2 computes the LU factorization of a general m-by-n matrix using partial pivoting with row interchanges (unblocked algorithm).

🌈 Function/Subroutine Documentation 🌈

🌸 subroutine ZGETF2 🌸

subroutine ZGETF2 (integer m, integer n, complex*16, dimension( lda, * ) a,
    integer lda, integer, dimension( * ) ipiv, integer info)

ZGETF2 computes the LU factorization of a general m-by-n matrix using partial pivoting with row interchanges (unblocked algorithm).

💜 Purpose 💜

The purpose is literally this: ZGETF2 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.

🍓 Parameters 🍓

• M — M is INTEGER and it's the number of rows of the matrix A. M >= 0.
• N — N is INTEGER and it's the number of columns of the matrix A. N >= 0.
• A — A is COMPLEX*16 array, dimension (LDA,N). On entry, it's the m by n matrix to be factored. On exit, it holds the factors L and U from the factorization A = P*L*U; the unit diagonal elements of L are not stored.
• LDA — LDA is INTEGER and it's the leading dimension of the array A. LDA >= max(1,M).
• IPIV — IPIV is INTEGER array, dimension (min(M,N)). These are the pivot indices; for 1 <= i <= min(M,N), row i of the matrix was interchanged with row IPIV(i).
• INFO — INFO is INTEGER and it's giving exit-status realness:
  • = 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.

bestie if INFO > 0, that U is exactly singular and division by zero will occur if it's used to solve a system of equations 😭 that's not a drill.

👑 Author 👑

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

Definition at line 107 of file zgetf2.f.

🫶 Author 🫶

Generated automatically by Doxygen for LAPACK from the source code.

---

xoxo, that's the whole page 💅 the footer energy is LAPACK Version 3.12.0 and /home/abui...RC/zgetf2.f(3) — slay ✨🫶