---
name: "dgetf2"
section: "3lapack"
platform: "linux"
package: "liblapack-doc"
version: "3.2.1-8"
release: "Debian 6.0 (Squeeze)"
platforms: ["linux"]
url: "https://new.carta.tech/dgetf2/3lapack"
---

# dgetf2(3lapack)

computes an LU factorization of a general m-by-n matrix A using partial pivoting with row interchanges

## NAME

DGETF2 - computes an LU factorization of a general m-by-n matrix A using partial pivoting with row interchanges

## SYNOPSIS

- SUBROUTINE DGETF2(

  M, N, A, LDA, IPIV, INFO )

- INTEGER

  INFO, LDA, M, N

- INTEGER

  IPIV( \* )

- DOUBLE

  PRECISION A( LDA, \* )

## PURPOSE

DGETF2 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.

## 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) DOUBLE PRECISION 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 (input) INTEGER

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

- IPIV (output) 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 (output) 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.