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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
NAG Ltd.
Date:
September 2012
Definition at line 115 of file zung2l.f.

# Author

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