ZGESC2(3)

💅 ZGESC2(3) — like, the zgesc2.f manual page, bestie

okay so this one lives at /home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/zgesc2.f — it's a Library Functions Manual situation, and it's from LAPACK, and it's about solving linear systems like a total icon. Let's get into it 🫶

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✨ SYNOPSIS ✨

Functions/Subroutines

subroutine ZGESC2 (n, a, lda, rhs, ipiv, jpiv, scale)

ZGESC2 solves a system of linear equations using the LU factorization with complete pivoting computed by sgetc2.

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🧚 Function/Subroutine Documentation 🧚

subroutine ZGESC2 (integer n, complex*16, dimension( lda, * ) a, integer
    lda, complex*16, dimension( * ) rhs, integer, dimension( * ) ipiv,
    integer, dimension( * ) jpiv, double precision scale)

ZGESC2 solves a system of linear equations using the LU factorization with complete pivoting computed by sgetc2. (yes that's the exact same sentence twice, it's giving "the subroutine contains the subroutine," but we keep it, it's canon 💀)

🎯 Purpose:

!>
!> ZGESC2 solves a system of linear equations
!>
!>           A * X = scale* RHS
!>
!> with a general N-by-N matrix A using the LU factorization with
!> complete pivoting computed by ZGETC2.
!>
!>

so yeah — you hand it the LU factorization that ZGETC2 already did for you, and it hands you back the solution. teamwork, bestie 🌈

🌸 Parameters 🌸

• N — N is INTEGER. the number of columns of the matrix A. that's it, that's the vibe ✨
• A — A is COMPLEX*16 array, dimension (LDA, N). on entry, this is the LU part of the factorization of the n-by-n matrix A computed by ZGETC2: A = P * L * U * Q. so don't bring a fresh matrix, bring the leftover crumbs from ZGETC2, she already did the work 👑
• LDA — LDA is INTEGER. the leading dimension of the array A. and the rule is LDA >= max(1, N). no cap, respect the bound 🙈
• RHS — RHS is COMPLEX*16 array, dimension N. on entry, the right hand side vector b. on exit, the solution vector X. glow-up of the century, honestly — it literally becomes a different vector in place 🔥
• IPIV — IPIV is INTEGER array, dimension (N). the pivot indices; for 1 <= i <= N, row i of the matrix has been interchanged with row IPIV(i). receipts of where every row went 🎀
• JPIV — JPIV is INTEGER array, dimension (N). the pivot indices; for 1 <= j <= N, column j of the matrix has been interchanged with column JPIV(j). same energy but for the columns, slay 🦋
• SCALE — SCALE is DOUBLE PRECISION. on exit, SCALE contains the scale factor. SCALE is chosen 0 <= SCALE <= 1 to prevent overflow in the solution. teeny tiny number, huge responsibility 💜

💖 Author 💖

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

🧑‍🤝‍🧑 Contributors: 🧑‍🤝‍🧑

Bo Kagstrom and Peter Poromaa, Department of Computing Science, Umea University, S-901 87 Umea, Sweden.

the way that address is fully spelled out, we love a complete citation 🍓

⭐ Definition at line 114 of file zgesc2.f. ⭐

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🎀 Author (again, yes) 🎀

Generated automatically by Doxygen for LAPACK from the source code.

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ngl bestie, if you're reading this to fix your own linear system: ZGETC2 first, then ZGESC2, in that order. that's the whole plot 💅

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mwah 💋 that's a wrap, bestie — this gorgeous little page is LAPACK, Version 3.12.0, and it's dated right there in the footer path /home/abui...RC/zgesc2.f(3). see you in the group chat 🫶✨