DLAQZ4(3)

okay bestie, welcome to DLAQZ4(3) from the Library Functions Manual — page path: /home/abui...RC/dlaqz4.f(3). It’s a LAPACK thing, it’s giving major main character energy, and we’re gonna get through every single parameter together. 🫶💅

🌸 NAME 🌸

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/dlaqz4.f — that’s the file, periodt. 💖

✨ SYNOPSIS ✨

🧚 Functions/Subroutines 🧚

Here’s the callable in all its multishift-QZ-sweep glory:

       subroutine DLAQZ4 (ilschur, ilq, ilz, n, ilo, ihi, nshifts,
           nblock_desired, sr, si, ss, a, lda, b, ldb, q, ldq, z, ldz, qc,
           ldqc, zc, ldzc, work, lwork, info)
           DLAQZ4

💖 FUNCTION/SUBROUTINE DOCUMENTATION 💖

🦋 subroutine DLAQZ4 (full signature) 🦋

subroutine DLAQZ4 (logical, intent(in) ilschur, logical, intent(in) ilq,
    logical, intent(in) ilz, integer, intent(in) n, integer, intent(in) ilo,
    integer, intent(in) ihi, integer, intent(in) nshifts, integer,
    intent(in) nblock_desired, double precision, dimension( * ),
    intent(inout) sr, double precision, dimension( * ), intent(inout) si,
    double precision, dimension( * ), intent(inout) ss, double precision,
    dimension( lda, * ), intent(inout) a, integer, intent(in) lda, double
    precision, dimension( ldb, * ), intent(inout) b, integer, intent(in)
    ldb, double precision, dimension( ldq, * ), intent(inout) q, integer,
    intent(in) ldq, double precision, dimension( ldz, * ), intent(inout) z,
    integer, intent(in) ldz, double precision, dimension( ldqc, * ),
    intent(inout) qc, integer, intent(in) ldqc, double precision, dimension(
    ldzc, * ), intent(inout) zc, integer, intent(in) ldzc, double precision,
    dimension( * ), intent(inout) work, integer, intent(in) lwork, integer,
    intent(out) info)
    DLAQZ4

🌟 Purpose: 🌟

!>
!> DLAQZ4 Executes a single multishift QZ sweep
!>

Translation: it runs a single multishift QZ sweep. That’s the whole purpose. Iconic. 💅

🎀 Parameters 🎀

• ILSCHUR — ILSCHUR is LOGICAL; it determines whether or not to update the full Schur form.
• ILQ — ILQ is LOGICAL; determines whether or not to update the matrix Q.
• ILZ — ILZ is LOGICAL; determines whether or not to update the matrix Z.
• N — N is INTEGER; The order of the matrices A, B, Q, and Z. N >= 0.
• ILO — ILO is INTEGER.
• IHI — IHI is INTEGER.
• NSHIFTS — NSHIFTS is INTEGER; The desired number of shifts to use.
• NBLOCK_DESIRED — NBLOCK_DESIRED is INTEGER; The desired size of the computational windows.
• SR — SR is DOUBLE PRECISION array. SR contains the real parts of the shifts to use.
• SI — SI is DOUBLE PRECISION array. SI contains the imaginary parts of the shifts to use.
• SS — SS is DOUBLE PRECISION array. SS contains the scale of the shifts to use.
• A — A is DOUBLE PRECISION array, dimension (LDA, N).
• LDA — LDA is INTEGER; The leading dimension of the array A. LDA >= max( 1, N ).
• B — B is DOUBLE PRECISION array, dimension (LDB, N).
• LDB — LDB is INTEGER; The leading dimension of the array B. LDB >= max( 1, N ).
• Q — Q is DOUBLE PRECISION array, dimension (LDQ, N).
• LDQ — LDQ is INTEGER.
• Z — Z is DOUBLE PRECISION array, dimension (LDZ, N).
• LDZ — LDZ is INTEGER.
• QC — QC is DOUBLE PRECISION array, dimension (LDQC, NBLOCK_DESIRED).
• LDQC — LDQC is INTEGER.
• ZC — ZC is DOUBLE PRECISION array, dimension (LDZC, NBLOCK_DESIRED).
• LDZC — LDZ is INTEGER. yes bestie, the page says LDZ here, not LDZC — I’m not fixing it, I’m just reporting it 💀
• WORK — WORK is DOUBLE PRECISION array, dimension (MAX(1,LWORK)). On exit, if INFO >= 0, WORK(1) returns the optimal LWORK.
• LWORK — LWORK is INTEGER; The dimension of the array WORK. LWORK >= max(1,N).

If LWORK = -1, then a workspace query is assumed; the routine only calculates the optimal size of the WORK array, returns this value as the first entry of the WORK array, and no error message related to LWORK is issued by XERBLA.

• INFO — INFO is INTEGER; = 0: successful exit; < 0: if INFO = -i, the i-th argument had an illegal value.

🌸 Author 🌸

Thijs Steel, KU Leuven — iconic. 👑

💜 Date 💜

May 2020.

Definition: Definition at line 209 of file dlaqz4.f.

🌈 Author 🌈

Generated automatically by Doxygen for LAPACK from the source code. — yes bestie, the robots wrote this one. 🤖💖

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okay that’s the whole page! LAPACK, Version 3.12.0, May 2020, page path /home/abui...RC/dlaqz4.f(3). slay and goodbye 💖✨🎀