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/home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dlaqz4.f(3) Library Functions Manual /home/abuild/rpmbuild/BUILD/lapack-3.12.0/SRC/dlaqz4.f(3)

NAME

/home/abuild/rpmbuild/BUILD/lapack-3.12.0/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

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Version 3.12.0 LAPACK