| Carlos Hernandez | 7faaa9f | 2014-08-05 17:53:32 -0700 | [diff] [blame] | 1 | *> \brief \b ILADLR |
| 2 | * |
| 3 | * =========== DOCUMENTATION =========== |
| 4 | * |
| 5 | * Online html documentation available at |
| 6 | * http://www.netlib.org/lapack/explore-html/ |
| 7 | * |
| 8 | *> \htmlonly |
| 9 | *> Download ILADLR + dependencies |
| 10 | *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/iladlr.f"> |
| 11 | *> [TGZ]</a> |
| 12 | *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/iladlr.f"> |
| 13 | *> [ZIP]</a> |
| 14 | *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/iladlr.f"> |
| 15 | *> [TXT]</a> |
| 16 | *> \endhtmlonly |
| 17 | * |
| 18 | * Definition: |
| 19 | * =========== |
| 20 | * |
| 21 | * INTEGER FUNCTION ILADLR( M, N, A, LDA ) |
| 22 | * |
| 23 | * .. Scalar Arguments .. |
| 24 | * INTEGER M, N, LDA |
| 25 | * .. |
| 26 | * .. Array Arguments .. |
| 27 | * DOUBLE PRECISION A( LDA, * ) |
| 28 | * .. |
| 29 | * |
| 30 | * |
| 31 | *> \par Purpose: |
| 32 | * ============= |
| 33 | *> |
| 34 | *> \verbatim |
| 35 | *> |
| 36 | *> ILADLR 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 DOUBLE PRECISION 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 | *> \date April 2012 |
| 75 | * |
| 76 | *> \ingroup auxOTHERauxiliary |
| 77 | * |
| 78 | * ===================================================================== |
| 79 | INTEGER FUNCTION ILADLR( M, N, A, LDA ) |
| 80 | * |
| 81 | * -- LAPACK auxiliary routine (version 3.4.1) -- |
| 82 | * -- LAPACK is a software package provided by Univ. of Tennessee, -- |
| 83 | * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- |
| 84 | * April 2012 |
| 85 | * |
| 86 | * .. Scalar Arguments .. |
| 87 | INTEGER M, N, LDA |
| 88 | * .. |
| 89 | * .. Array Arguments .. |
| 90 | DOUBLE PRECISION A( LDA, * ) |
| 91 | * .. |
| 92 | * |
| 93 | * ===================================================================== |
| 94 | * |
| 95 | * .. Parameters .. |
| 96 | DOUBLE PRECISION ZERO |
| 97 | PARAMETER ( ZERO = 0.0D+0 ) |
| 98 | * .. |
| 99 | * .. Local Scalars .. |
| 100 | INTEGER I, J |
| 101 | * .. |
| 102 | * .. Executable Statements .. |
| 103 | * |
| 104 | * Quick test for the common case where one corner is non-zero. |
| 105 | IF( M.EQ.0 ) THEN |
| 106 | ILADLR = M |
| 107 | ELSE IF( A(M, 1).NE.ZERO .OR. A(M, N).NE.ZERO ) THEN |
| 108 | ILADLR = M |
| 109 | ELSE |
| 110 | * Scan up each column tracking the last zero row seen. |
| 111 | ILADLR = 0 |
| 112 | DO J = 1, N |
| 113 | I=M |
| 114 | DO WHILE((A(MAX(I,1),J).EQ.ZERO).AND.(I.GE.1)) |
| 115 | I=I-1 |
| 116 | ENDDO |
| 117 | ILADLR = MAX( ILADLR, I ) |
| 118 | END DO |
| 119 | END IF |
| 120 | RETURN |
| 121 | END |