[1850] | 1 | !> @file random_function_mod.f90 |
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[2000] | 2 | !------------------------------------------------------------------------------! |
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[2696] | 3 | ! This file is part of the PALM model system. |
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[1036] | 4 | ! |
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[2000] | 5 | ! PALM is free software: you can redistribute it and/or modify it under the |
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| 6 | ! terms of the GNU General Public License as published by the Free Software |
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| 7 | ! Foundation, either version 3 of the License, or (at your option) any later |
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| 8 | ! version. |
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[1036] | 9 | ! |
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| 10 | ! PALM is distributed in the hope that it will be useful, but WITHOUT ANY |
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| 11 | ! WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR |
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| 12 | ! A PARTICULAR PURPOSE. See the GNU General Public License for more details. |
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| 13 | ! |
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| 14 | ! You should have received a copy of the GNU General Public License along with |
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| 15 | ! PALM. If not, see <http://www.gnu.org/licenses/>. |
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| 16 | ! |
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[2718] | 17 | ! Copyright 1997-2018 Leibniz Universitaet Hannover |
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[2000] | 18 | !------------------------------------------------------------------------------! |
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[1036] | 19 | ! |
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[484] | 20 | ! Current revisions: |
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[1] | 21 | ! ----------------- |
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[1343] | 22 | ! |
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[2001] | 23 | ! |
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[1321] | 24 | ! Former revisions: |
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| 25 | ! ----------------- |
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| 26 | ! $Id: random_function_mod.f90 2718 2018-01-02 08:49:38Z raasch $ |
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[2716] | 27 | ! Corrected "Former revisions" section |
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| 28 | ! |
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| 29 | ! 2696 2017-12-14 17:12:51Z kanani |
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| 30 | ! Change in file header (GPL part) |
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[1321] | 31 | ! |
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[2716] | 32 | ! 2101 2017-01-05 16:42:31Z suehring |
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| 33 | ! |
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[2001] | 34 | ! 2000 2016-08-20 18:09:15Z knoop |
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| 35 | ! Forced header and separation lines into 80 columns |
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| 36 | ! |
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[1851] | 37 | ! 1850 2016-04-08 13:29:27Z maronga |
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| 38 | ! Module renamed |
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| 39 | ! |
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| 40 | ! |
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[1683] | 41 | ! 1682 2015-10-07 23:56:08Z knoop |
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| 42 | ! Code annotations made doxygen readable |
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| 43 | ! |
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[1343] | 44 | ! 1342 2014-03-26 17:04:47Z kanani |
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| 45 | ! REAL constants defined as wp-kind |
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| 46 | ! |
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[1321] | 47 | ! 1320 2014-03-20 08:40:49Z raasch |
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[1320] | 48 | ! ONLY-attribute added to USE-statements, |
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| 49 | ! kind-parameters added to all INTEGER and REAL declaration statements, |
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| 50 | ! kinds are defined in new module kinds, |
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| 51 | ! old module precision_kind is removed, |
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| 52 | ! revision history before 2012 removed, |
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| 53 | ! comment fields (!:) to be used for variable explanations added to |
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| 54 | ! all variable declaration statements |
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[1] | 55 | ! |
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[1093] | 56 | ! 1092 2013-02-02 11:24:22Z raasch |
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| 57 | ! unused variables removed |
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| 58 | ! |
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[1037] | 59 | ! 1036 2012-10-22 13:43:42Z raasch |
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| 60 | ! code put under GPL (PALM 3.9) |
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| 61 | ! |
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[3] | 62 | ! RCS Log replace by Id keyword, revision history cleaned up |
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| 63 | ! |
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[1] | 64 | ! Revision 1.1 1998/02/04 16:09:45 raasch |
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| 65 | ! Initial revision |
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| 66 | ! |
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| 67 | ! |
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| 68 | ! Description: |
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| 69 | ! ------------ |
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[1682] | 70 | !> Random number generator, produces numbers equally distributed in interval [0,1] |
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| 71 | !> This routine is taken from the "numerical recipies" |
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[3] | 72 | !------------------------------------------------------------------------------! |
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[1682] | 73 | MODULE random_function_mod |
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| 74 | |
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[1] | 75 | |
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[1320] | 76 | USE kinds |
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| 77 | |
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[1] | 78 | IMPLICIT NONE |
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| 79 | |
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| 80 | PRIVATE |
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| 81 | |
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| 82 | PUBLIC random_function, random_function_ini |
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| 83 | |
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[1682] | 84 | INTEGER(iwp), PUBLIC, SAVE :: random_iv(32) !< |
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| 85 | INTEGER(iwp), PUBLIC, SAVE :: random_iy !< |
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[1] | 86 | |
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| 87 | INTERFACE random_function_ini |
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| 88 | MODULE PROCEDURE random_function_ini |
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| 89 | END INTERFACE random_function_ini |
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| 90 | |
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| 91 | INTERFACE random_function |
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| 92 | MODULE PROCEDURE random_function |
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| 93 | END INTERFACE random_function |
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| 94 | |
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| 95 | CONTAINS |
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| 96 | |
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[1682] | 97 | !------------------------------------------------------------------------------! |
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| 98 | ! Description: |
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| 99 | ! ------------ |
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| 100 | !> @todo Missing subroutine description. |
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| 101 | !------------------------------------------------------------------------------! |
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[1] | 102 | SUBROUTINE random_function_ini |
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| 103 | |
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| 104 | IMPLICIT NONE |
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| 105 | |
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| 106 | random_iv = 0 |
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| 107 | random_iy = 0 |
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| 108 | |
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| 109 | END SUBROUTINE random_function_ini |
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| 110 | |
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| 111 | FUNCTION random_function( idum ) |
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| 112 | |
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| 113 | |
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| 114 | IMPLICIT NONE |
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| 115 | |
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[1682] | 116 | INTEGER(iwp) :: ia !< |
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| 117 | INTEGER(iwp) :: idum !< |
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| 118 | INTEGER(iwp) :: im !< |
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| 119 | INTEGER(iwp) :: iq !< |
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| 120 | INTEGER(iwp) :: ir !< |
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| 121 | INTEGER(iwp) :: ndiv !< |
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| 122 | INTEGER(iwp) :: ntab !< |
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[1] | 123 | |
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[1682] | 124 | INTEGER(iwp) :: j !< |
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| 125 | INTEGER(iwp) :: k !< |
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[1320] | 126 | |
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[1682] | 127 | REAL(wp) :: am !< |
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| 128 | REAL(wp) :: eps !< |
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| 129 | REAL(wp) :: random_function !< |
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| 130 | REAL(wp) :: rnmx !< |
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[1320] | 131 | |
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[1342] | 132 | PARAMETER ( ia=16807, im=2147483647, am=1.0_wp/im, iq=127773, ir=2836, & |
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| 133 | ntab=32, ndiv=1+(im-1)/ntab, eps=1.2e-7_wp, rnmx=1.0_wp-eps ) |
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[1] | 134 | |
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| 135 | IF ( idum .le. 0 .or. random_iy .eq. 0 ) THEN |
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| 136 | idum = max (-idum,1) |
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| 137 | DO j = ntab+8,1,-1 |
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| 138 | k = idum / iq |
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| 139 | idum = ia * ( idum - k * iq ) - ir * k |
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| 140 | IF ( idum .lt. 0 ) idum = idum + im |
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| 141 | IF ( j .le. ntab ) random_iv(j) = idum |
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| 142 | ENDDO |
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| 143 | random_iy = random_iv(1) |
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| 144 | ENDIF |
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| 145 | |
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| 146 | k = idum / iq |
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| 147 | idum = ia * ( idum - k * iq ) - ir * k |
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| 148 | IF ( idum .lt. 0 ) idum = idum + im |
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| 149 | j = 1 + random_iy / ndiv |
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| 150 | random_iy = random_iv(j) |
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| 151 | random_iv(j) = idum |
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| 152 | random_function = min ( am * random_iy , rnmx ) |
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| 153 | |
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| 154 | END FUNCTION random_function |
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| 155 | |
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| 156 | END MODULE random_function_mod |
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