CGETC2(3)

🎀 cgetc2.f(3) — Library Functions Manual 🎀

Header tea bestie: the title/path stamp is /home/abui...RC/cgetc2.f(3), and yes the manual name is Library Functions Manual. This page is giving LAPACK, level 1 BLAS, complete pivoting, main character energy 💅✨.

🎀 NAME 🎀

The NAME section is literally this path, no cap:

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/cgetc2.f

✨ SYNOPSIS ✨

🌈 Functions/Subroutines 🌈

subroutine CGETC2 (n, a, lda, ipiv, jpiv, info)

CGETC2 computes the LU factorization with complete pivoting of the general n-by-n matrix. That's the whole synopsis, and it ate 💖.

💖 Function/Subroutine Documentation 💖

subroutine CGETC2 (integer n, complex, dimension( lda, * ) a, integer lda,
    integer, dimension( * ) ipiv, integer, dimension( * ) jpiv, integer
    info)

CGETC2 computes the LU factorization with complete pivoting of the general n-by-n matrix.

🌸 Purpose 🌸

Okay so CGETC2 computes an LU factorization, using complete pivoting, of the n-by-n matrix A. The factorization has the form A = P * L * U * Q, where P and Q are permutation matrices, L is lower triangular with unit diagonal elements and U is upper triangular. Periodt.

This is a level 1 BLAS version of the algorithm. Lowkey iconic, highkey old-school 🧚.

🧚 Parameters 🧚

• N — N is INTEGER. The order of the matrix A. N >= 0.
• A — A is COMPLEX array, dimension (LDA, N). On entry, the n-by-n matrix to be factored. On exit, the factors L and U from the factorization A = P*L*U*Q; the unit diagonal elements of L are not stored. If U(k, k) appears to be less than SMIN, U(k, k) is given the value of SMIN, giving a nonsingular perturbed system.
• LDA — LDA is INTEGER. The leading dimension of the array A. LDA >= max(1, N).
• 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).
• 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).
• INFO — INFO is INTEGER.
  • = 0: successful exit.
  • > 0: if INFO = k, U(k, k) is likely to produce overflow if one tries to solve for x in Ax = b. So U is perturbed to avoid the overflow.

bestie, that INFO > 0 case is not a drill: it means overflow was likely and the code perturbed U to dodge it. do not ignore it 💀.

👑 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. slay, thank you for your service 🎀.

⭐ Definition at line ⭐

Definition at line 110 of file cgetc2.f.

💅 Author (Doxygen's little signature) 💅

Generated automatically by Doxygen for LAPACK from the source code.

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Okay bestie that's the whole page 🫶 — it's from LAPACK Version 3.12.0, with footer path /home/abui...RC/cgetc2.f(3). The original footer has no date slot filled in, so no fake date from me; consider this your cute sign-off 💖✨.