SRC/dlaqz1.f(3)

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version 3.12.1 · 6 versions
, in arch rolling

🎀 SRC/dlaqz1.f(3) 🎀

okay so welcome to the Library Functions Manual, bestie — this page is all about the SRC/dlaqz1.f file and the dlaqz1 subroutine. it’s giving QZ algorithm bulge starter energy, and honestly? iconic. 💅✨

✨ NAME ✨

SRC/dlaqz1.f

💖 SYNOPSIS 💖

🧚 Functions/Subroutines 🧚

  • subroutine dlaqz1 (a, lda, b, ldb, sr1, sr2, si, beta1, beta2, v) — DLAQZ1

🌸 Function/Subroutine Documentation 🌸

🫶 Function signature 🫶

subroutine dlaqz1 (double precision, dimension( lda, * ), intent(in) a, integer, intent(in) lda, double precision, dimension( ldb, * ), intent(in) b, integer, intent(in) ldb, double precision, intent(in) sr1, double precision, intent(in) sr2, double precision, intent(in) si, double precision, intent(in) beta1, double precision, intent(in) beta2, double precision, dimension( * ), intent(out) v)

DLAQZ1

🎯 Purpose 🎯

Given a 3-by-3 matrix pencil (A,B), DLAQZ1 sets v to a scalar multiple of the first column of the product:

(*)  K = (A - (beta2*sr2 - i*si)*B)*B^(-1)*(beta1*A - (sr2 + i*si2)*B)*B^(-1).

fr fr, it is assumed that either

1) sr1 = sr2
or
2) si = 0.

this is useful for starting double implicit shift bulges in the QZ algorithm. no cap. 💫

🧸 Parameters 🧸

  • A — A is DOUBLE PRECISION array, dimension (LDA,N). the 3-by-3 matrix A in (*).
  • LDA — LDA is INTEGER. the leading dimension of A as declared in the calling procedure.
  • B — B is DOUBLE PRECISION array, dimension (LDB,N). the 3-by-3 matrix B in (*).
  • LDB — LDB is INTEGER. the leading dimension of B as declared in the calling procedure.
  • SR1 — SR1 is DOUBLE PRECISION.
  • SR2 — SR2 is DOUBLE PRECISION.
  • SI — SI is DOUBLE PRECISION.
  • BETA1 — BETA1 is DOUBLE PRECISION.
  • BETA2 — BETA2 is DOUBLE PRECISION.
  • V — V is DOUBLE PRECISION array, dimension (N). a scalar multiple of the first column of the matrix K in (*).

👑 Author 👑

Thijs Steel, KU Leuven

🗓️ Date 🗓️

May 2020

Definition at line 125 of file dlaqz1.f.

💫 Author 💫

Generated automatically by Doxygen for LAPACK from the source code.

mwah 💋 that’s the whole page, bestie. source/version vibes: LAPACK, Version 3.12.0; page source: SRC/dlaqz1.f(3); date: May 2020. slay. 🎀🦋💖

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