zlaqz3()

subroutine zlaqz3	(	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,
		complex*16, dimension( * ), intent(inout)	alpha,
		complex*16, dimension( * ), intent(inout)	beta,
		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,
		complex*16, dimension( ldqc, * ), intent(inout)	qc,
		integer, intent(in)	ldqc,
		complex*16, dimension( ldzc, * ), intent(inout)	zc,
		integer, intent(in)	ldzc,
		complex*16, dimension( * ), intent(inout)	work,
		integer, intent(in)	lwork,
		integer, intent(out)	info )

ZLAQZ3

Download ZLAQZ3 + dependencies [TGZ] [ZIP] [TXT]

Purpose:

!>
!> ZLAQZ3 Executes a single multishift QZ sweep
!> 

Parameters

[in]	ILSCHUR	!> ILSCHUR is LOGICAL !> Determines whether or not to update the full Schur form !>
[in]	ILQ	!> ILQ is LOGICAL !> Determines whether or not to update the matrix Q !>
[in]	ILZ	!> ILZ is LOGICAL !> Determines whether or not to update the matrix Z !>
[in]	N	!> N is INTEGER !> The order of the matrices A, B, Q, and Z. N >= 0. !>
[in]	ILO	!> ILO is INTEGER !>
[in]	IHI	!> IHI is INTEGER !>
[in]	NSHIFTS	!> NSHIFTS is INTEGER !> The desired number of shifts to use !>
[in]	NBLOCK_DESIRED	!> NBLOCK_DESIRED is INTEGER !> The desired size of the computational windows !>
[in]	ALPHA	!> ALPHA is COMPLEX*16 array. SR contains !> the alpha parts of the shifts to use. !>
[in]	BETA	!> BETA is COMPLEX*16 array. SS contains !> the scale of the shifts to use. !>
[in,out]	A	!> A is COMPLEX*16 array, dimension (LDA, N) !>
[in]	LDA	!> LDA is INTEGER !> The leading dimension of the array A. LDA >= max( 1, N ). !>
[in,out]	B	!> B is COMPLEX*16 array, dimension (LDB, N) !>
[in]	LDB	!> LDB is INTEGER !> The leading dimension of the array B. LDB >= max( 1, N ). !>
[in,out]	Q	!> Q is COMPLEX*16 array, dimension (LDQ, N) !>
[in]	LDQ	!> LDQ is INTEGER !>
[in,out]	Z	!> Z is COMPLEX*16 array, dimension (LDZ, N) !>
[in]	LDZ	!> LDZ is INTEGER !>
[in,out]	QC	!> QC is COMPLEX*16 array, dimension (LDQC, NBLOCK_DESIRED) !>
[in]	LDQC	!> LDQC is INTEGER !>
[in,out]	ZC	!> ZC is COMPLEX*16 array, dimension (LDZC, NBLOCK_DESIRED) !>
[in]	LDZC	!> LDZ is INTEGER !>
[out]	WORK	!> WORK is COMPLEX*16 array, dimension (MAX(1,LWORK)) !> On exit, if INFO >= 0, WORK(1) returns the optimal LWORK. !>
[in]	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. !>
[out]	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