1 | !********************************************************************** |
---|
2 | ! Copyright 1998,1999,2000,2001,2002,2005,2007,2008,2009,2010 * |
---|
3 | ! Andreas Stohl, Petra Seibert, A. Frank, Gerhard Wotawa, * |
---|
4 | ! Caroline Forster, Sabine Eckhardt, John Burkhart, Harald Sodemann * |
---|
5 | ! * |
---|
6 | ! This file is part of FLEXPART. * |
---|
7 | ! * |
---|
8 | ! FLEXPART is free software: you can redistribute it and/or modify * |
---|
9 | ! it under the terms of the GNU General Public License as published by* |
---|
10 | ! the Free Software Foundation, either version 3 of the License, or * |
---|
11 | ! (at your option) any later version. * |
---|
12 | ! * |
---|
13 | ! FLEXPART is distributed in the hope that it will be useful, * |
---|
14 | ! but WITHOUT ANY WARRANTY; without even the implied warranty of * |
---|
15 | ! MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * |
---|
16 | ! GNU General Public License for more details. * |
---|
17 | ! * |
---|
18 | ! You should have received a copy of the GNU General Public License * |
---|
19 | ! along with FLEXPART. If not, see <http://www.gnu.org/licenses/>. * |
---|
20 | !********************************************************************** |
---|
21 | |
---|
22 | ! Taken from Press et al., Numerical Recipes |
---|
23 | |
---|
24 | module random_mod |
---|
25 | |
---|
26 | implicit none |
---|
27 | |
---|
28 | contains |
---|
29 | |
---|
30 | function ran1(idum) |
---|
31 | |
---|
32 | implicit none |
---|
33 | |
---|
34 | integer :: idum |
---|
35 | real :: ran1 |
---|
36 | integer,parameter :: ia=16807, im=2147483647, iq=127773, ir=2836 |
---|
37 | integer,parameter :: ntab=32, ndiv=1+(im-1)/ntab |
---|
38 | real,parameter :: am=1./im, eps=1.2e-7, rnmx=1.-eps |
---|
39 | integer :: j, k |
---|
40 | integer :: iv(ntab) = (/ (0,j=1,ntab) /) |
---|
41 | integer :: iy=0 |
---|
42 | |
---|
43 | if (idum.le.0.or.iy.eq.0) then |
---|
44 | idum=max(-idum,1) |
---|
45 | do j=ntab+8,1,-1 |
---|
46 | k=idum/iq |
---|
47 | idum=ia*(idum-k*iq)-ir*k |
---|
48 | if (idum.lt.0) idum=idum+im |
---|
49 | if (j.le.ntab) iv(j)=idum |
---|
50 | enddo |
---|
51 | iy=iv(1) |
---|
52 | endif |
---|
53 | k=idum/iq |
---|
54 | idum=ia*(idum-k*iq)-ir*k |
---|
55 | if (idum.lt.0) idum=idum+im |
---|
56 | j=1+iy/ndiv |
---|
57 | iy=iv(j) |
---|
58 | iv(j)=idum |
---|
59 | ran1=min(am*iy,rnmx) |
---|
60 | end function ran1 |
---|
61 | |
---|
62 | |
---|
63 | function gasdev(idum) |
---|
64 | |
---|
65 | implicit none |
---|
66 | |
---|
67 | integer :: idum |
---|
68 | real :: gasdev, fac, r, v1, v2 |
---|
69 | integer :: iset = 0 |
---|
70 | real :: gset = 0. |
---|
71 | |
---|
72 | if (iset.eq.0) then |
---|
73 | 1 v1=2.*ran3(idum)-1. |
---|
74 | v2=2.*ran3(idum)-1. |
---|
75 | r=v1**2+v2**2 |
---|
76 | if(r.ge.1.0 .or. r.eq.0.0) go to 1 |
---|
77 | fac=sqrt(-2.*log(r)/r) |
---|
78 | gset=v1*fac |
---|
79 | gasdev=v2*fac |
---|
80 | iset=1 |
---|
81 | else |
---|
82 | gasdev=gset |
---|
83 | iset=0 |
---|
84 | endif |
---|
85 | end function gasdev |
---|
86 | |
---|
87 | |
---|
88 | subroutine gasdev1(idum,random1,random2) |
---|
89 | |
---|
90 | implicit none |
---|
91 | |
---|
92 | integer :: idum |
---|
93 | real :: random1, random2, fac, v1, v2, r |
---|
94 | |
---|
95 | 1 v1=2.*ran3(idum)-1. |
---|
96 | v2=2.*ran3(idum)-1. |
---|
97 | r=v1**2+v2**2 |
---|
98 | if(r.ge.1.0 .or. r.eq.0.0) go to 1 |
---|
99 | fac=sqrt(-2.*log(r)/r) |
---|
100 | random1=v1*fac |
---|
101 | random2=v2*fac |
---|
102 | ! Limit the random numbers to lie within the interval -3 and +3 |
---|
103 | !************************************************************** |
---|
104 | if (random1.lt.-3.) random1=-3. |
---|
105 | if (random2.lt.-3.) random2=-3. |
---|
106 | if (random1.gt.3.) random1=3. |
---|
107 | if (random2.gt.3.) random2=3. |
---|
108 | end subroutine gasdev1 |
---|
109 | |
---|
110 | |
---|
111 | function ran3(idum) |
---|
112 | |
---|
113 | implicit none |
---|
114 | |
---|
115 | integer :: idum |
---|
116 | real :: ran3 |
---|
117 | |
---|
118 | integer,parameter :: mbig=1000000000, mseed=161803398, mz=0 |
---|
119 | real,parameter :: fac=1./mbig |
---|
120 | integer :: i,ii,inext,inextp,k |
---|
121 | integer :: mj,mk,ma(55) |
---|
122 | |
---|
123 | save inext,inextp,ma |
---|
124 | integer :: iff = 0 |
---|
125 | |
---|
126 | if(idum.lt.0.or.iff.eq.0)then |
---|
127 | iff=1 |
---|
128 | mj=mseed-iabs(idum) |
---|
129 | mj=mod(mj,mbig) |
---|
130 | ma(55)=mj |
---|
131 | mk=1 |
---|
132 | do i=1,54 |
---|
133 | ii=mod(21*i,55) |
---|
134 | ma(ii)=mk |
---|
135 | mk=mj-mk |
---|
136 | if(mk.lt.mz)mk=mk+mbig |
---|
137 | mj=ma(ii) |
---|
138 | end do |
---|
139 | do k=1,4 |
---|
140 | do i=1,55 |
---|
141 | ma(i)=ma(i)-ma(1+mod(i+30,55)) |
---|
142 | if(ma(i).lt.mz)ma(i)=ma(i)+mbig |
---|
143 | end do |
---|
144 | end do |
---|
145 | inext=0 |
---|
146 | inextp=31 |
---|
147 | idum=1 |
---|
148 | endif |
---|
149 | inext=inext+1 |
---|
150 | if(inext.eq.56)inext=1 |
---|
151 | inextp=inextp+1 |
---|
152 | if(inextp.eq.56)inextp=1 |
---|
153 | mj=ma(inext)-ma(inextp) |
---|
154 | if(mj.lt.mz)mj=mj+mbig |
---|
155 | ma(inext)=mj |
---|
156 | ran3=mj*fac |
---|
157 | end function ran3 |
---|
158 | ! (C) Copr. 1986-92 Numerical Recipes Software US. |
---|
159 | |
---|
160 | end module random_mod |
---|