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Copy pathLennard-Jones Liquid.~f
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Lennard-Jones Liquid.~f
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program LennardJonesLiquid
implicit none
integer L,N,MCS,i,j,k,d, sim_time, check_time, m
parameter (L=20, MCS=230000, sim_time = 30000, check_time = 100)
real r_c, x_step, y_step,r_step, ran1, P, dr, ro, PI, T
parameter (r_c = 2.5, x_step = 0.01,y_step = 0.01,r_step = 0.02,
& dr = 0.05 ,PI = 3.141592653, ro = 0.95, T = 0.7)
! 0.8 - liquid & 0.93 - solid
real xnew, ynew, dx, dy, r_ij2, Rnew2, dU, r, Probability, Rmax
real dx_new, dy_new
integer counter, r_size, mcs_size
real, allocatable:: x(:), y(:), Prob(:,:)
d =-1
Rmax = L/3.0 - 1.0
!--------
r_size = int( Rmax/r_step + 1.0 )
mcs_size = int( (mcs-sim_time)/check_time + 1.0)
!---------- matrix places
N = int( ro*L**2 + 0.0)
write(*,*) 'N = ', N
allocate (x(N), y(N), Prob(r_size,mcs_size) )
call Liquid(L,N,x,y)
do i=1, r_size
do j=1, mcs_size
Prob(i,j) = 0.0
enddo
enddo
call showmatrix(N,x,y)
write(*,*) 'MCS'
counter = 1
do k=1, MCS
do i=1, N
dU = 0
xnew = x(i) + (ran1(d)-0.5)*x_step
ynew = y(i) + (ran1(d)-0.5)*y_step
if(xnew.gt.L) xnew = xnew - L
if(ynew.gt.L) ynew = ynew - L
if(xnew.lt.0.) xnew = xnew + L
if(ynew.lt.0.) ynew = ynew + L
do j=1, N
if(j.ne.i) then
dx = abs( x(i) - x(j) )
dy = abs( y(i) - y(j) )
if(dx.gt.L/2.) dx = L - dx
if(dy.gt.L/2.) dy = L - dy
r_ij2 = dx**2 + dy**2
dx_new = abs( xnew-x(j) )
dy_new = abs( ynew-y(j) )
if(dx_new.gt.L/2.) dx_new = L - dx_new
if(dy_new.gt.L/2.) dy_new = L - dy_new
Rnew2 = dx_new**2 + dy_new**2
if(Rnew2.le.1.0) goto 7
!r^2<=1 then r<=1, sqrt() not needed
if(r_ij2.le.r_c.and.Rnew2.le.r_c) then
dU = dU + 4.0*(1/Rnew2**6 - 1/r_ij2**6)
endif
endif
enddo
if(ran1(d).le.min(1.0,exp(-dU/T))) then
x(i) = xnew
y(i) = ynew
endif
7 continue
enddo
if(k.ge.sim_time.and.mod(k,check_time).eq.0) then
r = 1.0
m = INT(1/r_step - 1.0)
33 continue
Prob(m,counter) = Prob(m,counter) +
& Probability(r,dr,N,L,ro,x,y) !probabilistic matrix
r = r + r_step
m = m + 1
if(r.le.Rmax) goto 33
counter = counter + 1
endif
write(*,*) k
enddo
write(*,*) '----------------------------------'
write(*,*) 'Probability', ' ', 'r'
call save_prob(Prob,r_size,mcs_size,r_step)
call showmatrix(N,x,y)
pause
!call showmatrix(N,x,y)
end program
function Probability(r,dr,N,L,ro,x,y)
integer i, N, j, L
real dr, deltaR2, r, x(N), y(N)
real P, Probability, PI, ro, dx, dy
PI = 3.141592653
P = 0
Probability = P
if(r.le.dr) return
do j=1, N
M = 0
do i=1, N
dx = abs( x(i) - x(j) )
dy = abs( y(i) - y(j) )
if(dx.gt.L/2.) dx = L - dx
if(dy.gt.L/2.) dy = L - dy
deltaR2 = sqrt( dx**2 + dy**2 )
if(deltaR2.gt.r-dr.and.deltaR2.le.r) then
M = M + 1
endif
enddo
P = P + M/(2.0*PI*r*dr*ro)
!ring width: r-dr to r
enddo
Probability = P/(N+0.0)
return
end
subroutine Liquid(L,N,x,y)
integer L, N, M, k
real x(N), y(N), d, free_space
x(1) = 0.5
y(1) = 0.5
M = (L-1)*(L-2)
k = int(sqrt(N+0.0))
free_space = (L-1.0)/(k+0.0) - 1.0
if(N.ge.M) then
d = 1.0
else
d = 1.0 + free_space
endif
write (*,*) 'd = ',d
do i=2, N
y(i) = y(i-1)
x(i) = x(i-1) + d
if(x(i).gt.L-0.5) then
y(i) = y(i) + d
x(i) = 0.5
endif
enddo
end
subroutine showmatrix(n,x,y)
integer n
real x(n), y(n)
open(99,file='matrix-0.95.txt')
do i=1, n
write(99,*) x(i), y(i)
enddo
close(99)
end
subroutine save_prob(Prob, A, B, dr)
integer A,B, i, j
real Prob(A,B), P
open(13,file='prob-solid.txt')
do i=1, A
P = 0.0
do j=1, B
P = P + Prob(i,j)
enddo
P = P/(B+0.0)
write(13,*) i*dr, P
write(*,*) i*dr, P
enddo
close(13)
end
FUNCTION ran1(idum)
INTEGER idum,IA,IM,IQ,IR,NTAB,NDIV
REAL ran1,AM,EPS,RNMX
PARAMETER (IA=16807,IM=2147483647,AM=1./IM,IQ=127773,IR=2836,
*NTAB=32,NDIV=1+(IM-1)/NTAB,EPS=1.2e-7,RNMX=1.-EPS)
INTEGER j,k,iv(NTAB),iy
SAVE iv,iy
DATA iv /NTAB*0/, iy /0/
if (idum.le.0.or.iy.eq.0) then
idum=max(-idum,1)
do 11 j=NTAB+8,1,-1
k=idum/IQ
idum=IA*(idum-k*IQ)-IR*k
if (idum.lt.0) idum=idum+IM
if (j.le.NTAB) iv(j)=idum
11 continue
iy=iv(1)
endif
k=idum/IQ
idum=IA*(idum-k*IQ)-IR*k
if (idum.lt.0) idum=idum+IM
j=1+iy/NDIV
iy=iv(j)
iv(j)=idum
ran1=min(AM*iy,RNMX)
return
END