```      SUBROUTINE CGETF2( M, N, A, LDA, IPIV, INFO )
*
*  -- LAPACK routine (version 3.1) --
*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
*     November 2006
*
*     .. Scalar Arguments ..
INTEGER            INFO, LDA, M, N
*     ..
*     .. Array Arguments ..
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 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.
*
*  =====================================================================
*
*     .. Parameters ..
COMPLEX            ONE, ZERO
PARAMETER          ( ONE = ( 1.0E+0, 0.0E+0 ),
\$                   ZERO = ( 0.0E+0, 0.0E+0 ) )
*     ..
*     .. Local Scalars ..
REAL               SFMIN
INTEGER            I, J, JP
*     ..
*     .. External Functions ..
REAL               SLAMCH
INTEGER            ICAMAX
EXTERNAL           SLAMCH, ICAMAX
*     ..
*     .. External Subroutines ..
EXTERNAL           CGERU, CSCAL, CSWAP, XERBLA
*     ..
*     .. Intrinsic Functions ..
INTRINSIC          MAX, MIN
*     ..
*     .. Executable Statements ..
*
*     Test the input parameters.
*
INFO = 0
IF( M.LT.0 ) THEN
INFO = -1
ELSE IF( N.LT.0 ) THEN
INFO = -2
ELSE IF( LDA.LT.MAX( 1, M ) ) THEN
INFO = -4
END IF
IF( INFO.NE.0 ) THEN
CALL XERBLA( 'CGETF2', -INFO )
RETURN
END IF
*
*     Quick return if possible
*
IF( M.EQ.0 .OR. N.EQ.0 )
\$   RETURN
*
*     Compute machine safe minimum
*
SFMIN = SLAMCH('S')
*
DO 10 J = 1, MIN( M, N )
*
*        Find pivot and test for singularity.
*
JP = J - 1 + ICAMAX( M-J+1, A( J, J ), 1 )
IPIV( J ) = JP
IF( A( JP, J ).NE.ZERO ) THEN
*
*           Apply the interchange to columns 1:N.
*
IF( JP.NE.J )
\$         CALL CSWAP( N, A( J, 1 ), LDA, A( JP, 1 ), LDA )
*
*           Compute elements J+1:M of J-th column.
*
IF( J.LT.M ) THEN
IF( ABS(A( J, J )) .GE. SFMIN ) THEN
CALL CSCAL( M-J, ONE / A( J, J ), A( J+1, J ), 1 )
ELSE
DO 20 I = 1, M-J
A( J+I, J ) = A( J+I, J ) / A( J, J )
20             CONTINUE
END IF
END IF
*
ELSE IF( INFO.EQ.0 ) THEN
*
INFO = J
END IF
*
IF( J.LT.MIN( M, N ) ) THEN
*
*           Update trailing submatrix.
*
CALL CGERU( M-J, N-J, -ONE, A( J+1, J ), 1, A( J, J+1 ),
\$                  LDA, A( J+1, J+1 ), LDA )
END IF
10 CONTINUE
RETURN
*
*     End of CGETF2
*
END

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