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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