zung2l.f man page

zung2l.f —

Synopsis

Functions/Subroutines

subroutine zung2l (M, N, K, A, LDA, TAU, WORK, INFO)
ZUNG2L generates all or part of the unitary matrix Q from a QL factorization determined by cgeqlf (unblocked algorithm).

Function/Subroutine Documentation

subroutine zung2l (integerM, integerN, integerK, complex*16, dimension( lda, * )A, integerLDA, complex*16, dimension( * )TAU, complex*16, dimension( * )WORK, integerINFO)

ZUNG2L generates all or part of the unitary matrix Q from a QL factorization determined by cgeqlf (unblocked algorithm).

Purpose:

ZUNG2L generates an m by n complex matrix Q with orthonormal columns,
which is defined as the last n columns of a product of k elementary
reflectors of order m

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

as returned by ZGEQLF.

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 (n-k+i)-th column must contain the vector which
defines the elementary reflector H(i), for i = 1,2,...,k, as
returned by ZGEQLF in the last 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 ZGEQLF.

WORK

WORK is COMPLEX*16 array, dimension (N)

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:

September 2012

Definition at line 115 of file zung2l.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

zung2l(3) is an alias of zung2l.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK