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    1: *> \brief \b ILAZLR scans a matrix for its last non-zero row.
    2: *
    3: *  =========== DOCUMENTATION ===========
    4: *
    5: * Online html documentation available at
    6: *            http://www.netlib.org/lapack/explore-html/
    7: *
    8: *> \htmlonly
    9: *> Download ILAZLR + dependencies
   10: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/ilazlr.f">
   11: *> [TGZ]</a>
   12: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/ilazlr.f">
   13: *> [ZIP]</a>
   14: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/ilazlr.f">
   15: *> [TXT]</a>
   16: *> \endhtmlonly
   17: *
   18: *  Definition:
   19: *  ===========
   20: *
   21: *       INTEGER FUNCTION ILAZLR( M, N, A, LDA )
   22: *
   23: *       .. Scalar Arguments ..
   24: *       INTEGER            M, N, LDA
   25: *       ..
   26: *       .. Array Arguments ..
   27: *       COMPLEX*16         A( LDA, * )
   28: *       ..
   29: *
   30: *
   31: *> \par Purpose:
   32: *  =============
   33: *>
   34: *> \verbatim
   35: *>
   36: *> ILAZLR scans A for its last non-zero row.
   37: *> \endverbatim
   38: *
   39: *  Arguments:
   40: *  ==========
   41: *
   42: *> \param[in] M
   43: *> \verbatim
   44: *>          M is INTEGER
   45: *>          The number of rows of the matrix A.
   46: *> \endverbatim
   47: *>
   48: *> \param[in] N
   49: *> \verbatim
   50: *>          N is INTEGER
   51: *>          The number of columns of the matrix A.
   52: *> \endverbatim
   53: *>
   54: *> \param[in] A
   55: *> \verbatim
   56: *>          A is COMPLEX*16 array, dimension (LDA,N)
   57: *>          The m by n matrix A.
   58: *> \endverbatim
   59: *>
   60: *> \param[in] LDA
   61: *> \verbatim
   62: *>          LDA is INTEGER
   63: *>          The leading dimension of the array A. LDA >= max(1,M).
   64: *> \endverbatim
   65: *
   66: *  Authors:
   67: *  ========
   68: *
   69: *> \author Univ. of Tennessee
   70: *> \author Univ. of California Berkeley
   71: *> \author Univ. of Colorado Denver
   72: *> \author NAG Ltd.
   73: *
   74: *> \ingroup complex16OTHERauxiliary
   75: *
   76: *  =====================================================================
   77:       INTEGER FUNCTION ILAZLR( M, N, A, LDA )
   78: *
   79: *  -- LAPACK auxiliary routine --
   80: *  -- LAPACK is a software package provided by Univ. of Tennessee,    --
   81: *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
   82: *
   83: *     .. Scalar Arguments ..
   84:       INTEGER            M, N, LDA
   85: *     ..
   86: *     .. Array Arguments ..
   87:       COMPLEX*16         A( LDA, * )
   88: *     ..
   89: *
   90: *  =====================================================================
   91: *
   92: *     .. Parameters ..
   93:       COMPLEX*16       ZERO
   94:       PARAMETER ( ZERO = (0.0D+0, 0.0D+0) )
   95: *     ..
   96: *     .. Local Scalars ..
   97:       INTEGER I, J
   98: *     ..
   99: *     .. Executable Statements ..
  100: *
  101: *     Quick test for the common case where one corner is non-zero.
  102:       IF( M.EQ.0 ) THEN
  103:          ILAZLR = M
  104:       ELSE IF( A(M, 1).NE.ZERO .OR. A(M, N).NE.ZERO ) THEN
  105:          ILAZLR = M
  106:       ELSE
  107: *     Scan up each column tracking the last zero row seen.
  108:          ILAZLR = 0
  109:          DO J = 1, N
  110:             I=M
  111:             DO WHILE((A(MAX(I,1),J).EQ.ZERO).AND.(I.GE.1))
  112:                I=I-1
  113:             ENDDO
  114:             ILAZLR = MAX( ILAZLR, I )
  115:          END DO
  116:       END IF
  117:       RETURN
  118:       END