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INTEGER FUNCTION ILADLR( M, N, A, LDA )
IMPLICIT NONE
*
* -- LAPACK auxiliary routine (version 3.3.1) --
* -- LAPACK is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
* -- April 2011 --
*
* .. Scalar Arguments ..
INTEGER M, N, LDA
* ..
* .. Array Arguments ..
DOUBLE PRECISION A( LDA, * )
* ..
*
* Purpose
* =======
*
* ILADLR scans A for its last non-zero row.
*
* 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, J
* ..
* .. Executable Statements ..
*
* Quick test for the common case where one corner is non-zero.
IF( M.EQ.0 ) THEN
ILADLR = M
ELSE IF( A(M, 1).NE.ZERO .OR. A(M, N).NE.ZERO ) THEN
ILADLR = M
ELSE
* Scan up each column tracking the last zero row seen.
ILADLR = 0
DO J = 1, N
I = M
DO WHILE ((A(I,J).EQ.ZERO).AND.(I.GT.1))
I=I-1
ENDDO
IF( (I.EQ.1).AND.(A(1,J).EQ.ZERO) ) THEN
I = 0
END IF
ILADLR = MAX( ILADLR, I )
END DO
END IF
RETURN
END
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