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zungqr(3) [debian man page]

zungqr.f(3)							      LAPACK							       zungqr.f(3)

NAME

       zungqr.f -

SYNOPSIS

   Functions/Subroutines
       subroutine zungqr (M, N, K, A, LDA, TAU, WORK, LWORK, INFO)
	   ZUNGQR

Function/Subroutine Documentation
   subroutine zungqr (integerM, integerN, integerK, complex*16, dimension( lda, * )A, integerLDA, complex*16, dimension( * )TAU, complex*16,
       dimension( * )WORK, integerLWORK, integerINFO)
       ZUNGQR

       Purpose:

	    ZUNGQR generates an M-by-N complex matrix Q with orthonormal columns,
	    which is defined as the first N columns of a product of K elementary
	    reflectors of order M

		  Q  =	H(1) H(2) . . . H(k)

	    as returned by ZGEQRF.

       Parameters:
	   M

		     M is INTEGER
		     The number of rows of the matrix Q. M >= 0.

	   N

		     N is INTEGER
		     The number of columns of the matrix Q. M >= N >= 0.

	   K

		     K is INTEGER
		     The number of elementary reflectors whose product defines the
		     matrix Q. N >= K >= 0.

	   A

		     A is COMPLEX*16 array, dimension (LDA,N)
		     On entry, the i-th column must contain the vector which
		     defines the elementary reflector H(i), for i = 1,2,...,k, as
		     returned by ZGEQRF in the first k columns of its array
		     argument A.
		     On exit, the M-by-N matrix Q.

	   LDA

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

	   TAU

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

	   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 >= max(1,N).
		     For optimum performance LWORK >= N*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 has an illegal value

       Author:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   November 2011

       Definition at line 129 of file zungqr.f.

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

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

Check Out this Related Man Page

ZUNGQR(l)								 )								 ZUNGQR(l)

NAME

       ZUNGQR - generate an M-by-N complex matrix Q with orthonormal columns,

SYNOPSIS

       SUBROUTINE ZUNGQR( M, N, K, A, LDA, TAU, WORK, LWORK, INFO )

	   INTEGER	  INFO, K, LDA, LWORK, M, N

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

PURPOSE

       ZUNGQR  generates an M-by-N complex matrix Q with orthonormal columns, which is defined as the first N columns of a product of K elementary
       reflectors of order M

	     Q	=  H(1) H(2) . . . H(k)

       as returned by ZGEQRF.

ARGUMENTS

       M       (input) INTEGER
	       The number of rows of the matrix Q. M >= 0.

       N       (input) INTEGER
	       The number of columns of the matrix Q. M >= N >= 0.

       K       (input) INTEGER
	       The number of elementary reflectors whose product defines the matrix Q. N >= K >= 0.

       A       (input/output) COMPLEX*16 array, dimension (LDA,N)
	       On entry, the i-th column must contain the vector which defines the elementary reflector H(i), for i = 1,2,...,k,  as  returned	by
	       ZGEQRF in the first k columns of its array argument A.  On exit, the M-by-N matrix Q.

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

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

       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 >= max(1,N).  For optimum performance LWORK >= N*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    (output) INTEGER
	       = 0:  successful exit
	       < 0:  if INFO = -i, the i-th argument has an illegal value

LAPACK version 3.0						   15 June 2000 							 ZUNGQR(l)
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