| 1 | *> \brief \b ILASLR
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| 2 | *
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| 3 | * =========== DOCUMENTATION ===========
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| 4 | *
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| 5 | * Online html documentation available at
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| 6 | * http://www.netlib.org/lapack/explore-html/
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| 7 | *
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| 8 | *> \htmlonly
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| 9 | *> Download ILASLR + dependencies
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| 10 | *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/ilaslr.f">
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| 11 | *> [TGZ]</a>
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| 12 | *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/ilaslr.f">
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| 13 | *> [ZIP]</a>
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| 14 | *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/ilaslr.f">
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| 15 | *> [TXT]</a>
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| 16 | *> \endhtmlonly
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| 17 | *
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| 18 | * Definition:
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| 19 | * ===========
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| 20 | *
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| 21 | * INTEGER FUNCTION ILASLR( M, N, A, LDA )
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| 22 | *
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| 23 | * .. Scalar Arguments ..
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| 24 | * INTEGER M, N, LDA
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| 25 | * ..
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| 26 | * .. Array Arguments ..
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| 27 | * REAL A( LDA, * )
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| 28 | * ..
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| 29 | *
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| 30 | *
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| 31 | *> \par Purpose:
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| 32 | * =============
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| 33 | *>
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| 34 | *> \verbatim
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| 35 | *>
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| 36 | *> ILASLR scans A for its last non-zero row.
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| 37 | *> \endverbatim
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| 38 | *
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| 39 | * Arguments:
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| 40 | * ==========
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| 41 | *
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| 42 | *> \param[in] M
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| 43 | *> \verbatim
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| 44 | *> M is INTEGER
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| 45 | *> The number of rows of the matrix A.
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| 46 | *> \endverbatim
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| 47 | *>
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| 48 | *> \param[in] N
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| 49 | *> \verbatim
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| 50 | *> N is INTEGER
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| 51 | *> The number of columns of the matrix A.
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| 52 | *> \endverbatim
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| 53 | *>
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| 54 | *> \param[in] A
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| 55 | *> \verbatim
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| 56 | *> A is REAL array, dimension (LDA,N)
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| 57 | *> The m by n matrix A.
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| 58 | *> \endverbatim
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| 59 | *>
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| 60 | *> \param[in] LDA
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| 61 | *> \verbatim
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| 62 | *> LDA is INTEGER
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| 63 | *> The leading dimension of the array A. LDA >= max(1,M).
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| 64 | *> \endverbatim
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| 65 | *
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| 66 | * Authors:
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| 67 | * ========
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| 68 | *
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| 69 | *> \author Univ. of Tennessee
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| 70 | *> \author Univ. of California Berkeley
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| 71 | *> \author Univ. of Colorado Denver
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| 72 | *> \author NAG Ltd.
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| 73 | *
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| 74 | *> \date April 2012
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| 75 | *
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| 76 | *> \ingroup realOTHERauxiliary
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| 77 | *
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| 78 | * =====================================================================
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| 79 | INTEGER FUNCTION ILASLR( M, N, A, LDA )
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| 80 | *
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| 81 | * -- LAPACK auxiliary routine (version 3.4.1) --
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| 82 | * -- LAPACK is a software package provided by Univ. of Tennessee, --
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| 83 | * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
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| 84 | * April 2012
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| 85 | *
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| 86 | * .. Scalar Arguments ..
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| 87 | INTEGER M, N, LDA
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| 88 | * ..
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| 89 | * .. Array Arguments ..
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| 90 | REAL A( LDA, * )
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| 91 | * ..
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| 92 | *
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| 93 | * =====================================================================
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| 94 | *
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| 95 | * .. Parameters ..
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| 96 | REAL ZERO
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| 97 | PARAMETER ( ZERO = 0.0E+0 )
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| 98 | * ..
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| 99 | * .. Local Scalars ..
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| 100 | INTEGER I, J
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| 101 | * ..
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| 102 | * .. Executable Statements ..
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| 103 | *
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| 104 | * Quick test for the common case where one corner is non-zero.
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| 105 | IF( M.EQ.0 ) THEN
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| 106 | ILASLR = M
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| 107 | ELSEIF( A(M, 1).NE.ZERO .OR. A(M, N).NE.ZERO ) THEN
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| 108 | ILASLR = M
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| 109 | ELSE
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| 110 | * Scan up each column tracking the last zero row seen.
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| 111 | ILASLR = 0
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| 112 | DO J = 1, N
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| 113 | I=M
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| 114 | DO WHILE((A(MAX(I,1),J).EQ.ZERO).AND.(I.GE.1))
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| 115 | I=I-1
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| 116 | ENDDO
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| 117 | ILASLR = MAX( ILASLR, I )
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| 118 | END DO
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| 119 | END IF
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| 120 | RETURN
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| 121 | END
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