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

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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