# Ubuntu Feisty 7.04 manual page repository

Ubuntu is a free computer operating system based on the Linux kernel. Many IT companies, like DeployIS is using it to provide an up-to-date, stable operating system.

Provided by: lapack3-doc_3.0.20000531a-6ubuntu3_all

` `

### NAME

```        ZGEQL2 - compute a QL factorization of a complex m by n matrix A
```

### SYNOPSIS

```        SUBROUTINE ZGEQL2( M, N, A, LDA, TAU, WORK, INFO )

INTEGER        INFO, LDA, M, N

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

### PURPOSE

```        ZGEQL2  computes a QL factorization of a complex m by n matrix A: A = Q
* L.
```

### ARGUMENTS

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

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

A       (input/output) COMPLEX*16 array, dimension (LDA,N)
On entry, the m by n matrix A.  On exit, if m >= n,  the  lower
triangle  of  the  subarray  A(m-n+1:m,1:n) contains the n by n
lower triangular matrix L; if m <= n, the elements on and below
the (n-m)-th superdiagonal contain the m by n lower trapezoidal
matrix L; the remaining elements, with the array TAU, represent
the unitary matrix Q as a product of elementary reflectors (see
Further Details).  LDA     (input) INTEGER The  leading  dimen‐
sion of the array A.  LDA >= max(1,M).

TAU     (output) COMPLEX*16 array, dimension (min(M,N))
The  scalar  factors  of the elementary reflectors (see Further
Details).

WORK    (workspace) COMPLEX*16 array, dimension (N)

INFO    (output) INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
The matrix Q is represented as a product of elementary reflectors

H(1), where k = min(m,n).

Each H(i) has the form

H(i) = I - tau * v * v’

where tau is a complex scalar, and v is  a  complex  vector  with  v(m-
k+i+1:m) = 0 and v(m-k+i) = 1; v(1:m-k+i-1) is stored on exit in A(1:m-
k+i-1,n-k+i), and tau in TAU(i).

```
Sections

What does Ubuntu mean?
Ubuntu is an African word meaning 'Humanity to others', or 'I am what I am because of who we all are'. The Ubuntu distribution brings the spirit of Ubuntu to the software world.