SRC/slaqz1.f(3)

🌸 NAME 🌸

SRC/slaqz1.f — and this page comes from the Library Functions Manual, bestie, filed under SRC/slaqz1.f(3) 💖

---

✨ SYNOPSIS ✨

🧩 Functions/Subroutines

subroutine slaqz1 (a, lda, b, ldb, sr1, sr2, si, beta1, beta2, v)
    SLAQZ1

---

🫶 Function/Subroutine Documentation 🫶

👑 SLAQZ1

subroutine slaqz1 (real, dimension( lda, * ), intent(in) a, integer,
       intent(in) lda, real, dimension( ldb, * ), intent(in) b, integer,
       intent(in) ldb, real, intent(in) sr1, real, intent(in) sr2, real,
       intent(in) si, real, intent(in) beta1, real, intent(in) beta2, real,
       dimension( * ), intent(out) v)

SLAQZ1 — the subroutine, the icon, the whole vibe ✨

🎯 Purpose

Okay so picture this: you hand SLAQZ1 a 3-by-3 matrix pencil (A,B), and it sets v to a scalar multiple of the first column of the product. Literally what it does 💅

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

It is assumed that either

1. sr1 = sr2
2. si = 0

No cap, those are the assumptions 🫶 This is useful for starting double implicit shift bulges in the QZ algorithm.

📦 Parameters

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

🌟 Author

Thijs Steel, KU Leuven

📅 Date

May 2020

🔍 Definition

Definition at line 125 of file slaqz1.f.

---

🌈 Author 🌈

Generated automatically by Doxygen for LAPACK from the source code.

---

Byeee bestie 💅 — this iconic little page is from LAPACK Version 3.12.0, tagged as SRC/slaqz1.f(3). Mwah! 🎀