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Percolation/Mean run density: Difference between revisions
FORTRAN entry
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Line 162:
t=500, p=0.90, n= 4096, p(1-p)=0.09000, sim=0.09047, delta=0.5%
t=500, p=0.90, n=16384, p(1-p)=0.09000, sim=0.09007, delta=0.1%</pre>
=={{header|FORTRAN}}==
<lang>
! loosely translated from python. We do not need to generate and store the entire vector at once.
! compilation: gfortran -Wall -std=f2008 -o thisfile thisfile.f08
program percolation_mean_run_density
implicit none
integer :: i, p10, n2, n, t
real :: p, limit, sim, delta
data n,p,t/100,0.5,500/
write(6,'(a3,a5,4a7)')'t','p','n','p(1-p)','sim','delta'!a little tight!
do p10=1,10,2
p = p10/10.0
limit = p*(1-p)
write(6,'()')
do n2=10,15,2
n = 2**n2
sim = 0
do i=1,t
sim = sim + mean_run_density(n,p)
end do
sim = sim/t
if (limit /= 0) then
delta = abs(sim-limit)/limit
else
delta = sim
end if
delta = delta * 100
write(6,'(i3,f5.2,i7,2f7.3,f5.1)')t,p,n,limit,sim,delta
end do
end do
contains
integer function runs(n, p)
integer, intent(in) :: n
real, intent(in) :: p
real :: harvest
logical :: q
integer :: count, i
count = 0
q = .false.
do i=1,n
call random_number(harvest)
if (harvest < p) then
q = .true.
else
if (q) count = count+1
q = .false.
end if
end do
runs = count
end function runs
real function mean_run_density(n, p)
integer, intent(in) :: n
real, intent(in) :: p
mean_run_density = real(runs(n,p))/real(n)
end function mean_run_density
end program percolation_mean_run_density
</lang>
<pre>
$ ./f
t p n p(1-p) sim delta
500 0.10 1024 0.090 0.090 0.2
500 0.10 4096 0.090 0.090 0.2
500 0.10 16384 0.090 0.090 0.0
500 0.30 1024 0.210 0.210 0.2
500 0.30 4096 0.210 0.210 0.0
500 0.30 16384 0.210 0.210 0.0
500 0.50 1024 0.250 0.250 0.1
500 0.50 4096 0.250 0.250 0.1
500 0.50 16384 0.250 0.250 0.1
500 0.70 1024 0.210 0.210 0.1
500 0.70 4096 0.210 0.210 0.1
500 0.70 16384 0.210 0.210 0.0
500 0.90 1024 0.090 0.090 0.1
500 0.90 4096 0.090 0.090 0.4
500 0.90 16384 0.090 0.090 0.1
</pre>
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