ZUNGHR(3F)							    ZUNGHR(3F)

NAME    [Toc]    [Back]

     ZUNGHR - generate a complex unitary matrix	Q which	is defined as the
     product of	IHI-ILO	elementary reflectors of order N, as returned by
     ZGEHRD

SYNOPSIS    [Toc]    [Back]

     SUBROUTINE	ZUNGHR(	N, ILO,	IHI, A,	LDA, TAU, WORK,	LWORK, INFO )

	 INTEGER	IHI, ILO, INFO,	LDA, LWORK, N

	 COMPLEX*16	A( LDA,	* ), TAU( * ), WORK( LWORK )

PURPOSE    [Toc]    [Back]

     ZUNGHR generates a	complex	unitary	matrix Q which is defined as the
     product of	IHI-ILO	elementary reflectors of order N, as returned by
     ZGEHRD:

     Q = H(ilo)	H(ilo+1) . . . H(ihi-1).

ARGUMENTS    [Toc]    [Back]

     N	     (input) INTEGER
	     The order of the matrix Q.	N >= 0.

     ILO     (input) INTEGER
	     IHI     (input) INTEGER ILO and IHI must have the same values as
	     in	the previous call of ZGEHRD. Q is equal	to the unit matrix
	     except in the submatrix Q(ilo+1:ihi,ilo+1:ihi).  1	<= ILO <= IHI
	     <=	N, if N	> 0; ILO=1 and IHI=0, if N=0.

     A	     (input/output) COMPLEX*16 array, dimension	(LDA,N)
	     On	entry, the vectors which define	the elementary reflectors, as
	     returned by ZGEHRD.  On exit, the N-by-N unitary matrix Q.

     LDA     (input) INTEGER
	     The leading dimension of the array	A. LDA >= max(1,N).

     TAU     (input) COMPLEX*16	array, dimension (N-1)
	     TAU(i) must contain the scalar factor of the elementary reflector
	     H(i), as returned by ZGEHRD.

     WORK    (workspace/output)	COMPLEX*16 array, dimension (LWORK)
	     On	exit, if INFO =	0, WORK(1) returns the optimal LWORK.

     LWORK   (input) INTEGER
	     The dimension of the array	WORK. LWORK >= IHI-ILO.	 For optimum
	     performance LWORK >= (IHI-ILO)*NB,	where NB is the	optimal
	     blocksize.

     INFO    (output) INTEGER
	     = 0:  successful exit
	     < 0:  if INFO = -i, the i-th argument had an illegal value
ZUNGHR(3F)							    ZUNGHR(3F)

NAME    [Toc]    [Back]

     ZUNGHR - generate a complex unitary matrix	Q which	is defined as the
     product of	IHI-ILO	elementary reflectors of order N, as returned by
     ZGEHRD

SYNOPSIS    [Toc]    [Back]

     SUBROUTINE	ZUNGHR(	N, ILO,	IHI, A,	LDA, TAU, WORK,	LWORK, INFO )

	 INTEGER	IHI, ILO, INFO,	LDA, LWORK, N

	 COMPLEX*16	A( LDA,	* ), TAU( * ), WORK( LWORK )

PURPOSE    [Toc]    [Back]

     ZUNGHR generates a	complex	unitary	matrix Q which is defined as the
     product of	IHI-ILO	elementary reflectors of order N, as returned by
     ZGEHRD:

     Q = H(ilo)	H(ilo+1) . . . H(ihi-1).

ARGUMENTS    [Toc]    [Back]

     N	     (input) INTEGER
	     The order of the matrix Q.	N >= 0.

     ILO     (input) INTEGER
	     IHI     (input) INTEGER ILO and IHI must have the same values as
	     in	the previous call of ZGEHRD. Q is equal	to the unit matrix
	     except in the submatrix Q(ilo+1:ihi,ilo+1:ihi).  1	<= ILO <= IHI
	     <=	N, if N	> 0; ILO=1 and IHI=0, if N=0.

     A	     (input/output) COMPLEX*16 array, dimension	(LDA,N)
	     On	entry, the vectors which define	the elementary reflectors, as
	     returned by ZGEHRD.  On exit, the N-by-N unitary matrix Q.

     LDA     (input) INTEGER
	     The leading dimension of the array	A. LDA >= max(1,N).

     TAU     (input) COMPLEX*16	array, dimension (N-1)
	     TAU(i) must contain the scalar factor of the elementary reflector
	     H(i), as returned by ZGEHRD.

     WORK    (workspace/output)	COMPLEX*16 array, dimension (LWORK)
	     On	exit, if INFO =	0, WORK(1) returns the optimal LWORK.

     LWORK   (input) INTEGER
	     The dimension of the array	WORK. LWORK >= IHI-ILO.	 For optimum
	     performance LWORK >= (IHI-ILO)*NB,	where NB is the	optimal
	     blocksize.

     INFO    (output) INTEGER
	     = 0:  successful exit
	     < 0:  if INFO = -i, the i-th argument had an illegal value


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