sgetrf(l) [redhat man page]

SGETRF(l)								 )								 SGETRF(l)

NAME

       SGETRF - compute an LU factorization of a general M-by-N matrix A using partial pivoting with row interchanges

SYNOPSIS

       SUBROUTINE SGETRF( M, N, A, LDA, IPIV, INFO )

	   INTEGER	  INFO, LDA, M, N

	   INTEGER	  IPIV( * )

	   REAL 	  A( LDA, * )

PURPOSE

       SGETRF  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 3 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) 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 ele-
	       ments 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 = -i, the i-th argument had an illegal value
	       > 0:  if INFO = i, U(i,i) 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.

LAPACK version 3.0						   15 June 2000 							 SGETRF(l)

CGETRF(l)								 )								 CGETRF(l)

NAME

       CGETRF - compute an LU factorization of a general M-by-N matrix A using partial pivoting with row interchanges

SYNOPSIS

       SUBROUTINE CGETRF( M, N, A, LDA, IPIV, INFO )

	   INTEGER	  INFO, LDA, M, N

	   INTEGER	  IPIV( * )

	   COMPLEX	  A( LDA, * )

PURPOSE

       CGETRF  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 3 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) COMPLEX 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 ele-
	       ments 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 = -i, the i-th argument had an illegal value
	       > 0:  if INFO = i, U(i,i) 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.

LAPACK version 3.0						   15 June 2000 							 CGETRF(l)