SRC/dlaqz4.f(3)            Library Functions Manual            SRC/dlaqz4.f(3)

NAME
       SRC/dlaqz4.f

SYNOPSIS
   Functions/Subroutines
       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 (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

       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

           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

           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

       Date
           May 2020

       Definition at line 209 of file dlaqz4.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

LAPACK                          Version 3.12.0                 SRC/dlaqz4.f(3)