ilaclr()

integer function ilaclr	(	integer	M,
		integer	N,
		complex, dimension( lda, * )	A,
		integer	LDA
	)

ILACLR scans a matrix for its last non-zero row.

Download ILACLR + dependencies [TGZ] [ZIP] [TXT]

Purpose:

 ILACLR scans A for its last non-zero row.

Parameters

[in]	M	M is INTEGER The number of rows of the matrix A.
[in]	N	N is INTEGER The number of columns of the matrix A.
[in]	A	A is COMPLEX array, dimension (LDA,N) The m by n matrix A.
[in]	LDA	LDA is INTEGER The leading dimension of the array A. LDA >= max(1,M).

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date

June 2017

Definition at line 80 of file ilaclr.f.

*
*  -- LAPACK auxiliary routine (version 3.7.1) --
*  -- LAPACK is a software package provided by Univ. of Tennessee,    --
*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
*     June 2017
*
*     .. Scalar Arguments ..
      INTEGER            M, N, LDA
*     ..
*     .. Array Arguments ..
      COMPLEX            A( LDA, * )
*     ..
*
*  =====================================================================
*
*     .. Parameters ..
      COMPLEX          ZERO
      parameter( zero = (0.0e+0, 0.0e+0) )
*     ..
*     .. Local Scalars ..
      INTEGER I, J
*     ..
*     .. Executable Statements ..
*
*     Quick test for the common case where one corner is non-zero.
      IF( m.EQ.0 ) THEN
         ilaclr = m
      ELSE IF( a(m, 1).NE.zero .OR. a(m, n).NE.zero ) THEN
         ilaclr = m
      ELSE
*     Scan up each column tracking the last zero row seen.
         ilaclr = 0
         DO j = 1, n
            i=m
            DO WHILE((a(max(i,1),j).EQ.zero).AND.(i.GE.1))
               i=i-1
            ENDDO
            ilaclr = max( ilaclr, i )
         END DO
      END IF
      RETURN