# sgetf2.f man page

sgetf2.f —

## Synopsis

### Functions/Subroutines

subroutinesgetf2(M, N, A, LDA, IPIV, INFO)SGETF2computes the LU factorization of a general m-by-n matrix using partial pivoting with row interchanges (unblocked algorithm).

## Function/Subroutine Documentation

### subroutine sgetf2 (integerM, integerN, real, dimension( lda, * )A, integerLDA, integer, dimension( * )IPIV, integerINFO)

**SGETF2** computes the LU factorization of a general m-by-n matrix using partial pivoting with row interchanges (unblocked algorithm).

**Purpose:**

```
SGETF2 computes an LU factorization of a general m-by-n matrix A
using partial pivoting with row interchanges.
The factorization has the form
A = P * L * U
where P is a permutation matrix, L is lower triangular with unit
diagonal elements (lower trapezoidal if m > n), and U is upper
triangular (upper trapezoidal if m < n).
This is the right-looking Level 2 BLAS version of the algorithm.
```

**Parameters:**

*M*

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

*N*

```
N is INTEGER
The number of columns of the matrix A. N >= 0.
```

*A*

```
A is REAL array, dimension (LDA,N)
On entry, the m by n matrix to be factored.
On exit, the factors L and U from the factorization
A = P*L*U; the unit diagonal elements of L are not stored.
```

*LDA*

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

*IPIV*

```
IPIV is INTEGER array, dimension (min(M,N))
The pivot indices; for 1 <= i <= min(M,N), row i of the
matrix was interchanged with row IPIV(i).
```

*INFO*

```
INFO is INTEGER
= 0: successful exit
< 0: if INFO = -k, the k-th argument had an illegal value
> 0: if INFO = k, U(k,k) is exactly zero. The factorization
has been completed, but the factor U is exactly
singular, and division by zero will occur if it is used
to solve a system of equations.
```

**Author:**

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

**Date:**

September 2012

Definition at line 109 of file sgetf2.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

sgetf2(3) is an alias of sgetf2.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK