SRC/zlasyf_aa.f(3)

💅 SRC/zlasyf_aa.f 💅

okay bestie, welcome to the Library Functions Manual page for SRC/zlasyf_aa.f — that's the header/title vibe, and we're already iconic. This is a LAPACK subroutine page, so grab your iced coffee and let's get into it. ✨

💖 NAME 💖

SRC/zlasyf_aa.f — literally that. The NAME section is not doing extra credit today, and honestly? Respect. 🫶

✨ SYNOPSIS ✨

🧚 Functions/Subroutines 🧚

• subroutine zlasyf_aa (uplo, j1, m, nb, a, lda, ipiv, h, ldh, work) — the main character, aka ZLASYF_AA.

subroutine zlasyf_aa (uplo, j1, m, nb, a, lda, ipiv, h, ldh, work)
    ZLASYF_AA

🦋 Function/Subroutine Documentation 🦋

Here's the full signature, bestie — types and all:

subroutine zlasyf_aa (character uplo, integer j1, integer m, integer nb,
    complex*16, dimension( lda, * ) a, integer lda, integer, dimension( * )
    ipiv, complex*16, dimension( ldh, * ) h, integer ldh, complex*16,
    dimension( * ) work)
    ZLASYF_AA

🎀 Purpose 🎀

ok so the docs here start with DLATRF_AA — yes, that's what it says, bestie, not a typo I'm fixing — and it factorizes a panel of a complex symmetric matrix A using the Aasen's algorithm. The panel is a set of NB rows of A when UPLO is U, or a set of NB columns when UPLO is L. Periodt. 💅

To factorize the panel, Aasen's algorithm needs the last row, or column, of the previous panel. The first row, or column, of A is set to be the first row, or column, of an identity matrix, and that's what gets used to factorize the first panel. Cute. 🌸

The resulting J-th row of U, or J-th column of L, is stored in the (J-1)-th row, or column, of A — without the unit diagonals, bestie, don't forget. Meanwhile the diagonal and subdiagonal of A are overwritten by those of T. Slay. 🔥

💅 Parameters 💅

• UPLO — UPLO is CHARACTER*1
  • = 'U': Upper triangle of A is stored;
  • = 'L': Lower triangle of A is stored.
• J1 — J1 is INTEGER The location of the first row, or column, of the panel within the submatrix of A, passed to this routine, e.g., when called by ZSYTRF_AA, for the first panel, J1 is 1, while for the remaining panels, J1 is 2.
• M — M is INTEGER The dimension of the submatrix. M >= 0.
• NB — NB is INTEGER The dimension of the panel to be facotorized — yes, that's the spelling in the page, and I'm keeping it because details are sacred. 🫶
• A — A is COMPLEX*16 array, dimension (LDA,M) for the first panel, while dimension (LDA,M+1) for the remaining panels. On entry, A contains the last row, or column, of the previous panel, and the trailing submatrix of A to be factorized, except for the first panel, only the panel is passed. On exit, the leading panel is factorized.
• LDA — LDA is INTEGER The leading dimension of the array A. LDA >= max(1,M).
• IPIV — IPIV is INTEGER array, dimension (M) Details of the row and column interchanges: the row and column k were interchanged with the row and column IPIV(k).
• H — H is COMPLEX*16 workspace, dimension (LDH,NB)
• LDH — LDH is INTEGER The leading dimension of the workspace H. LDH >= max(1,M).
• WORK — WORK is COMPLEX*16 workspace, dimension (M)

👑 Author 👑

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

Definition at line 142 of file zlasyf_aa.f.

💀 Author 💀

Generated automatically by Doxygen for LAPACK from the source code.

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okay that's the page, bestie. The footer vibe is LAPACK, Version 3.12.0, and SRC/zlasyf_aa.f(3) — so you know exactly where this came from. bye bestie, go factorize something cute 💖✨