5 |
|
|
6 |
#undef _USE_INTEGERS |
#undef _USE_INTEGERS |
7 |
|
|
8 |
! ============================================================================== |
C---+----1----+----2----+----3----+----4----+----5----+----6----+----7-|--+----| |
9 |
CBOP |
CBOP |
10 |
C !ROUTINE: port_rand |
C !ROUTINE: port_rand |
11 |
C !INTERFACE: |
C !INTERFACE: |
12 |
real*8 function port_rand(seed) |
real*8 function port_rand(seed) |
13 |
|
|
14 |
C !DESCRIPTION: \bv |
C !DESCRIPTION: |
15 |
C Portable random number generator |
C Portable random number generator |
16 |
C \ev |
|
17 |
|
C !USES: |
18 |
|
implicit none |
19 |
|
CEOP |
20 |
|
|
21 |
C !LOCAL VARIABLES: |
C !LOCAL VARIABLES: |
|
implicit none |
|
22 |
integer nff |
integer nff |
23 |
parameter(nff=55) |
parameter(nff=55) |
24 |
#ifdef _USE_INTEGERS |
#ifdef _USE_INTEGERS |
44 |
logical firstCall |
logical firstCall |
45 |
save firstCall,inext,inextp,ma |
save firstCall,inext,inextp,ma |
46 |
data firstCall /.true./ |
data firstCall /.true./ |
47 |
CEOP |
|
|
! ------------------------------------------------------------------------------ |
|
48 |
mseed = seed |
mseed = seed |
49 |
if(firstCall)then |
if(firstCall)then |
50 |
firstCall=.false. |
firstCall=.false. |
75 |
ma(inext)=mj |
ma(inext)=mj |
76 |
port_rand=mj*fac |
port_rand=mj*fac |
77 |
return |
return |
78 |
! ------------------------------------------------------------------------------ |
|
79 |
end |
end |
|
! ============================================================================== |
|
80 |
|
|
81 |
! ============================================================================== |
C---+----1----+----2----+----3----+----4----+----5----+----6----+----7-|--+----| |
82 |
|
|
83 |
subroutine port_ranarr(n,arr) |
subroutine port_ranarr(n,arr) |
84 |
implicit none |
implicit none |
85 |
integer n,i |
integer n,i |
86 |
real arr(n) |
real arr(n) |
87 |
real*8 port_rand,seed |
real*8 port_rand,seed |
88 |
seed=1618033.0d0 |
seed=1618033.0d0 |
|
! ------------------------------------------------------------------------------ |
|
89 |
do i=1,n |
do i=1,n |
90 |
arr(i)=port_rand(seed) |
arr(i)=port_rand(seed) |
91 |
enddo |
enddo |
92 |
|
|
93 |
return |
return |
|
! ------------------------------------------------------------------------------ |
|
94 |
end |
end |
95 |
! ============================================================================== |
|
96 |
|
C---+----1----+----2----+----3----+----4----+----5----+----6----+----7-|--+----| |
97 |
|
CBOP |
98 |
|
C !ROUTINE: port_rand_norm |
99 |
|
C !INTERFACE: |
100 |
|
real*8 function port_rand_norm() |
101 |
|
|
102 |
|
C !DESCRIPTION: |
103 |
|
C This function generates a normally distributed random number with |
104 |
|
C the so called polar algorithm. The algorithm actually generates 2 |
105 |
|
C numbers, but only 1 is returned for maximum compatibility with old |
106 |
|
C code. The most obvious way to improve this function would be to |
107 |
|
C make sure that the second number is not wasted. |
108 |
|
|
109 |
|
C Changed: 2004.09.06 antti.westerlund@fimr.fi |
110 |
|
|
111 |
|
C !USES: |
112 |
|
implicit none |
113 |
|
CEOP |
114 |
|
|
115 |
|
C !LOCAL VARIABLES: |
116 |
|
real*8 port_rand,seed |
117 |
|
real*8 x1, x2, xs, t |
118 |
|
integer i |
119 |
|
|
120 |
|
seed=1618033.0d0 |
121 |
|
C first generate 2 equally distributed random numbers (-1,1) |
122 |
|
DO WHILE (1 .eq. 1) |
123 |
|
x1=2.0*port_rand(seed)-1.0 |
124 |
|
x2=2.0*port_rand(seed)-1.0 |
125 |
|
xs=x1**2+x2**2 |
126 |
|
if(xs .lt. 1.0 .and. xs .ne. 0.0) then |
127 |
|
goto 100 |
128 |
|
end if |
129 |
|
END DO |
130 |
|
100 continue |
131 |
|
|
132 |
|
t = sqrt(-2.0*log(xs)/xs) |
133 |
|
port_rand_norm = t*x1 |
134 |
|
C |
135 |
|
C also t*x2 would be a gaussian random number and could be returned |
136 |
|
|
137 |
|
return |
138 |
|
end |