[22] | 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 November 2011 |
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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 3.4.0) -- |
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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 | * November 2011 |
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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(I,J).NE.ZERO).AND.(I.GE.1)) |
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| 115 | I=I-1 |
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| 116 | IF (I.EQ.0) THEN |
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| 117 | EXIT |
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| 118 | END IF |
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| 119 | ENDDO |
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| 120 | ILASLR = MAX( ILASLR, I ) |
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| 121 | END DO |
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| 122 | END IF |
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| 123 | RETURN |
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| 124 | END |
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