SRC/zlaqz1.f(3)

NAME
SRC/zlaqz1.f

SYNOPSIS

  Functions/Subroutines
subroutine zlaqz1 (ilq, ilz, k, istartm, istopm, ihi, a, lda, b, ldb, nq, qstart, q, ldq, nz, zstart, z, ldz)
ZLAQZ1

Function/Subroutine Documentation

  subroutine zlaqz1 (logical, intent(in) ilq, logical, intent(in) ilz, integer, intent(in) k, integer, intent(in) istartm, integer, intent(in) istopm, integer, intent(in) ihi, complex*16, dimension( lda, * ) a, integer, intent(in) lda, complex*16, dimension( ldb, * ) b, integer, intent(in) ldb, integer, intent(in) nq, integer, intent(in) qstart, complex*16, dimension( ldq, * ) q, integer, intent(in) ldq, integer, intent(in) nz, integer, intent(in) zstart, complex*16, dimension( ldz, * ) z, integer, intent(in) ldz)

ZLAQZ1

Purpose:

          ZLAQZ1 chases a 1x1 shift bulge in a matrix pencil down a single position

Parameters
    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

    K

              K is INTEGER
                  Index indicating the position of the bulge.
                  On entry, the bulge is located in
                  (A(k+1,k),B(k+1,k)).
                  On exit, the bulge is located in
                  (A(k+2,k+1),B(k+2,k+1)).

    ISTARTM

              ISTARTM is INTEGER

    ISTOPM

              ISTOPM is INTEGER
                  Updates to (A,B) are restricted to
                  (istartm:k+2,k:istopm). It is assumed
                  without checking that istartm <= k+1 and
                  k+2 <= istopm

    IHI

              IHI is INTEGER

    A

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

    LDA

              LDA is INTEGER
                  The leading dimension of A as declared in
                  the calling procedure.

    B

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

    LDB

              LDB is INTEGER
                  The leading dimension of B as declared in
                  the calling procedure.

    NQ

              NQ is INTEGER
                  The order of the matrix Q

    QSTART

              QSTART is INTEGER
                  Start index of the matrix Q. Rotations are applied
                  To columns k+2-qStart:k+3-qStart of Q.

    Q

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

    LDQ

              LDQ is INTEGER
                  The leading dimension of Q as declared in
                  the calling procedure.

    NZ

              NZ is INTEGER
                  The order of the matrix Z

    ZSTART

              ZSTART is INTEGER
                  Start index of the matrix Z. Rotations are applied
                  To columns k+1-qStart:k+2-qStart of Z.

    Z

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

    LDZ

              LDZ is INTEGER
                  The leading dimension of Q as declared in
                  the calling procedure.

Author
    Thijs Steel, KU Leuven

Date
    May 2020

Definition at line 171 of file zlaqz1.f.

Author

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