Chimie Théorique » Opt'n Path

      INTEGER FUNCTION ILADLC(M, N, A, LDA)

      IMPLICIT NONE

!

!  -- LAPACK auxiliary routine (version 3.2) --

!     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..

!     December 2007

!

!     .. Scalar Arguments ..

      INTEGER            M, N, LDA

!     ..

!     .. Array Arguments ..

      DOUBLE PRECISION   A( LDA, * )

!     ..

!

!  Purpose

!  =======

!

!  ILADLC scans A for its last non-zero column.

!

!  Arguments

!  =========

!

!  M       (input) INTEGER

!          The number of rows of the matrix A.

!

!  N       (input) INTEGER

!          The number of columns of the matrix A.

!

!  A       (input) DOUBLE PRECISION array, dimension (LDA,N)

!          The m by n matrix A.

!

!  LDA     (input) INTEGER

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

!

!  =====================================================================

!

!     .. Parameters ..

      DOUBLE PRECISION ZERO

      PARAMETER ( ZERO = 0.0D+0 )

!     ..

!     .. Local Scalars ..

      INTEGER I

!     ..

!     .. Executable Statements ..

!

!     Quick test for the common case where one corner is non-zero.

      IF( N.EQ.0 .OR. A(1, N).NE.ZERO .OR. A(M, N).NE.ZERO ) THEN

         ILADLC = N

      ELSE

!     Now scan each column from the end, returning with the first non-zero.

         DO ILADLC = N, 1, -1

            DO I = 1, M

               IF( A(I, ILADLC).NE.ZERO ) RETURN

            END DO

         END DO

      END IF

      RETURN

      END FUNCTION