cgetf2(l) [redhat man page]

CGETF2(l)								 )								 CGETF2(l)

NAME

       CGETF2 - compute an LU factorization of a general m-by-n matrix A using partial pivoting with row interchanges

SYNOPSIS

       SUBROUTINE CGETF2( M, N, A, LDA, IPIV, INFO )

	   INTEGER	  INFO, LDA, M, N

	   INTEGER	  IPIV( * )

	   COMPLEX	  A( LDA, * )

PURPOSE

       CGETF2  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) 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 = -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.

LAPACK version 3.0						   15 June 2000 							 CGETF2(l)

ZGETF2(l)								 )								 ZGETF2(l)

NAME

       ZGETF2 - compute an LU factorization of a general m-by-n matrix A using partial pivoting with row interchanges

SYNOPSIS

       SUBROUTINE ZGETF2( M, N, A, LDA, IPIV, INFO )

	   INTEGER	  INFO, LDA, M, N

	   INTEGER	  IPIV( * )

	   COMPLEX*16	  A( LDA, * )

PURPOSE

       ZGETF2  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) COMPLEX*16 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 = -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.

LAPACK version 3.0						   15 June 2000 							 ZGETF2(l)