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zunghr(3) [debian man page]

zunghr.f(3)							      LAPACK							       zunghr.f(3)

NAME

       zunghr.f -

SYNOPSIS

   Functions/Subroutines
       subroutine zunghr (N, ILO, IHI, A, LDA, TAU, WORK, LWORK, INFO)
	   ZUNGHR

Function/Subroutine Documentation
   subroutine zunghr (integerN, integerILO, integerIHI, complex*16, dimension( lda, * )A, integerLDA, complex*16, dimension( * )TAU, complex*16,
       dimension( * )WORK, integerLWORK, integerINFO)
       ZUNGHR

       Purpose:

	    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).

       Parameters:
	   N

		     N is INTEGER
		     The order of the matrix Q. N >= 0.

	   ILO

		     ILO is INTEGER

	   IHI

		     IHI is 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

		     A is 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

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

	   TAU

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

	   WORK

		     WORK is COMPLEX*16 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 >= IHI-ILO.
		     For optimum performance LWORK >= (IHI-ILO)*NB, where NB is
		     the optimal blocksize.

		     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:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   November 2011

       Definition at line 127 of file zunghr.f.

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

Version 3.4.1							  Sun May 26 2013						       zunghr.f(3)

Check Out this Related Man Page

ZUNGHR(l)								 )								 ZUNGHR(l)

NAME

       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

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

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

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

PURPOSE

       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

       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  block-
	       size.

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

LAPACK version 3.0						   15 June 2000 							 ZUNGHR(l)
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