SRC/zlaqz2.f(3)

NAME
SRC/zlaqz2.f

SYNOPSIS

  Functions/Subroutines
recursive subroutine zlaqz2 (ilschur, ilq, ilz, n, ilo, ihi, nw, a, lda, b, ldb, q, ldq, z, ldz, ns, nd, alpha, beta, qc, ldqc, zc, ldzc, work, lwork, rwork, rec, info)
ZLAQZ2

Function/Subroutine Documentation

  recursive subroutine zlaqz2 (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, complex*16, dimension( lda, * ), intent(inout) a, integer, intent(in) lda, complex*16, dimension( ldb, * ), intent(inout) b, integer, intent(in) ldb, complex*16, dimension( ldq, * ), intent(inout) q, integer, intent(in) ldq, complex*16, dimension( ldz, * ), intent(inout) z, integer, intent(in) ldz, integer, intent(out) ns, integer, intent(out) nd, complex*16, dimension( * ), intent(inout) alpha, complex*16, dimension( * ), intent(inout) beta, complex*16, dimension( ldqc, * ) qc, integer, intent(in) ldqc, complex*16, dimension( ldzc, * ) zc, integer, intent(in) ldzc, complex*16, dimension( * ) work, integer, intent(in) lwork, double precision, dimension( * ) rwork, integer, intent(in) rec, integer, intent(out) info)

ZLAQZ2

Purpose:

     ZLAQZ2 performs AED

Parameters
    ILSCHUR

              ILSCHUR is LOGICAL
                  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
              ILO and IHI mark the rows and columns of (A,B) which
              are to be normalized

    NW

              NW is INTEGER
              The desired size of the deflation window.

    A

              A is COMPLEX*16 array, dimension (LDA, N)

    LDA

              LDA is INTEGER
              The leading dimension of the array A.  LDA >= max( 1, N ).

    B

              B is COMPLEX*16 array, dimension (LDB, N)

    LDB

              LDB is INTEGER
              The leading dimension of the array B.  LDB >= max( 1, N ).

    Q

              Q is COMPLEX*16 array, dimension (LDQ, N)

    LDQ

              LDQ is INTEGER

    Z

              Z is COMPLEX*16 array, dimension (LDZ, N)

    LDZ

              LDZ is INTEGER

    NS

              NS is INTEGER
              The number of unconverged eigenvalues available to
              use as shifts.

    ND

              ND is INTEGER
              The number of converged eigenvalues found.

    ALPHA

              ALPHA is COMPLEX*16 array, dimension (N)
              Each scalar alpha defining an eigenvalue
              of GNEP.

    BETA

              BETA is COMPLEX*16 array, dimension (N)
              The scalars beta that define the eigenvalues of GNEP.
              Together, the quantities alpha = ALPHA(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

              QC is COMPLEX*16 array, dimension (LDQC, NW)

    LDQC

              LDQC is INTEGER

    ZC

              ZC is COMPLEX*16 array, dimension (LDZC, NW)

    LDZC

              LDZ is INTEGER

    WORK

              WORK is COMPLEX*16 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.

    RWORK

              RWORK is DOUBLE PRECISION array, dimension (N)

    REC

              REC is INTEGER
                 REC indicates the current recursion level. Should be set
                 to 0 on first call.

    INFO

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

Author
    Thijs Steel, KU Leuven

Date
    May 2020

Definition at line 230 of file zlaqz2.f.

Author

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