SRC/dlaqz3.f(3)

🎀 NAME 🎀

SRC/dlaqz3.f — that's the file, bestie, and this page lives in the Library Functions Manual.

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✨ SYNOPSIS ✨

Functions/Subroutines

recursive subroutine dlaqz3 (ilschur, ilq, ilz, n, ilo, ihi, nw, a, lda,
    b, ldb, q, ldq, z, ldz, ns, nd, alphar, alphai, beta, qc, ldqc, zc,
    ldzc, work, lwork, rec, info)
    DLAQZ3

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🧚 Function/Subroutine Documentation 🌸

Here's the full signature, character-for-character:

recursive subroutine dlaqz3 (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) nw, 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, integer, intent(out) ns,
    integer, intent(out) nd, double precision, dimension( * ), intent(inout)
    alphar, double precision, dimension( * ), intent(inout) alphai, double
    precision, dimension( * ), intent(inout) beta, double precision,
    dimension( ldqc, * ) qc, integer, intent(in) ldqc, double precision,
    dimension( ldzc, * ) zc, integer, intent(in) ldzc, double precision,
    dimension( * ) work, integer, intent(in) lwork, integer, intent(in) rec,
    integer, intent(out) info)
    DLAQZ3

✨ Purpose ✨

!>
!> DLAQZ3 performs AED
!>

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💅 Parameters 💅

• ILSCHUR — LOGICAL, intent(in). It decides whether or not the full Schur form gets updated.
• ILQ — LOGICAL, intent(in). It decides whether or not matrix Q gets updated.
• ILZ — LOGICAL, intent(in). It decides whether or not matrix Z gets updated.
• N — INTEGER, intent(in). The order of matrices A, B, Q, and Z. N >= 0.
• ILO — INTEGER, intent(in). No extra note on this one in the original.
• IHI — INTEGER, intent(in). ILO and IHI mark the rows and columns of (A,B) which are to be normalized.
• NW — INTEGER, intent(in). The desired size of the deflation window.
• A — DOUBLE PRECISION array, dimension (LDA, N), intent(inout).
• LDA — INTEGER, intent(in). The leading dimension of the array A. LDA >= max( 1, N ).
• B — DOUBLE PRECISION array, dimension (LDB, N), intent(inout).
• LDB — INTEGER, intent(in). The leading dimension of the array B. LDB >= max( 1, N ).
• Q — DOUBLE PRECISION array, dimension (LDQ, N), intent(inout).
• LDQ — INTEGER, intent(in). No extra note in the original here.
• Z — DOUBLE PRECISION array, dimension (LDZ, N), intent(inout).
• LDZ — INTEGER, intent(in). No extra note in the original here.
• NS — INTEGER, intent(out). The number of unconverged eigenvalues available to use as shifts.
• ND — INTEGER, intent(out). The number of converged eigenvalues found.
• ALPHAR — DOUBLE PRECISION array, dimension (N), intent(inout). The real parts of each scalar alpha defining an eigenvalue of GNEP.
• ALPHAI — DOUBLE PRECISION array, dimension (N), intent(inout). The imaginary parts of each scalar alpha defining an eigenvalue of GNEP. If ALPHAI(j) is zero, then the j-th eigenvalue is real; if positive, then the j-th and (j+1)-st eigenvalues are a complex conjugate pair, with ALPHAI(j+1) = -ALPHAI(j).
• BETA — DOUBLE PRECISION array, dimension (N), intent(inout). The scalars beta that define the eigenvalues of GNEP. Together, the quantities alpha = (ALPHAR(j),ALPHAI(j)) and beta = BETA(j) represent the j-th eigenvalue of the matrix pair (A,B), in one of the forms lambda = alpha/beta or mu = beta/alpha. Since either lambda or mu may overflow, they should not, in general, be computed.
• QC — DOUBLE PRECISION array, dimension (LDQC, NW).
• LDQC — INTEGER, intent(in).
• ZC — DOUBLE PRECISION array, dimension (LDZC, NW).
• LDZC — INTEGER, intent(in). Heads up: the original also literally includes the line LDZ is INTEGER right here — yes, LDZ, not LDZC — and I'm keeping it exactly as written.
• WORK — DOUBLE PRECISION array, dimension (MAX(1,LWORK)). On exit, if INFO >= 0, WORK(1) returns the optimal LWORK.
• LWORK — INTEGER, intent(in). 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.
• REC — INTEGER, intent(in). REC indicates the current recursion level. Should be set to 0 on first call.
• INFO — INTEGER, intent(out). = 0: successful exit. < 0: if INFO = -i, the i-th argument had an illegal value.

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👑 Author 👑

Thijs Steel, KU Leuven. Absolute icon behavior.

🦋 Date 🦋

May 2020.

Definition at line 235 of file dlaqz3.f.

🤖 Author 🤖

Generated automatically by Doxygen for LAPACK from the source code.

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That's the whole page, bestie. This beauty is LAPACK Version 3.12.0, from SRC/dlaqz3.f(3), dated May 2020. 💖✨🎀