[Fortran90] how to declare in 2d arrays
Hi all, I have code for 2d fdtd in fortran as below:
Code:
!problem 3.9, Taflove chapter 3
!to model 2d TMz mode fdtd Simulation using Yee grid.
!time step deltat = (1/sqrt(2)*delta/c) is used
subroutine fd2d
implicit none
double precision :: f0 !frequency
double precision :: miu
double precision :: miur !permittivity
double precision :: miu0
double precision :: E0
double precision :: delta
double precision :: deltat
double precision :: deltax
double precision :: deltay
double precision :: sigma
double precision :: sigmastar
double precision :: Eps
double precision :: Eps0
double precision :: Epsr
double precision :: lambda
double precision :: lambdax
double precision :: lambday
double precision :: nlambdax
double precision :: nlambday
double precision :: omega
double precision :: S
double precision :: k
double precision :: c
integer :: i,j
integer :: m,p
integer :: mlast,plast
integer :: n
integer :: iinit
integer :: ilast
integer :: jinit
integer :: jlast
double precision,dimension(202,202):: Ez
double precision,dimension(202,202):: Hy
double precision,dimension(202,202):: Hx
double precision :: EzAmp
double precision :: HyAmp
double precision :: HxAmp
double precision :: Ca
double precision :: Cb
double precision :: Da
double precision :: Db
double precision, parameter :: pi = 3.14159265
character(len=20) :: filename
f0 = 100.0
miu0 = 1.0
miur = 1.0
Eps0 = 1.0
Epsr = 1.0
!delta = 1.e-3
delta = 0.1
lambda = c/f0
c = 1
E0 = 1
deltat = (delta/c)/sqrt(2.0)
k = 2*pi / lambda
omega = c*k
nlambdax = 5
nlambday = 5
lambdax = lambda
lambday = lambda
deltax = delta
deltay = delta
S = 1.0001
iinit = 1
ilast = 100
jinit = 1
jlast = 100
mlast = 2*ilast-1
plast = 2*jlast-1
print*, 'see me?'
!initialize Ez, Hx,Hy to zero at t=0
do p = 1,2*jlast
Ez(1,p-1) = 0
Ez(m-1,p-1) = 0
do m = 1,2*ilast
Hx(m+1,p) = 0
Hy(2*m,p) = 0
Ez(m+1,p-1) = 0
Ez(m+1,1) = 0
Ez(m+1,plast+2) = 0
end do
end do
!medium's properties
Ca(m,p) = 1.0
Cb(m,p) = deltat/(1-0.5*deltax)
!Print *,'Ca, Cb=',Ca, ' ',Cb
Da(m,p) = 1.0
Db(m,p) = deltat/deltax
!Print *, 'Da, Db=',Db, ' ',Db
!print*, 'see me?1'
!initiate sinusoidal wavepulse at center
do n = 1,100
do m = 1,2*ilast
do p = 1,2*jlast
Ez(101,101) = sin((n+1)*omega*deltat)
end do
end do
end do
do n = 1,200
write (filename, "('ez',I3.3,'.dat')") n
open (unit=130,file=filename)
do m = 1,2*ilast-1
do p = 1,2*jlast-1
if (Mod(m,2)/=0) then
if (Mod(p,2)/=0) then
Ez(m,p) = Ca*Ez(m,p-1)+Cb*(Hy(m+1,p-1)-Hy(i+1,p-1)+Hx(m+1,p+1)-Hx(m,p-1))
end if
end if
end do
end do
do m = 1,2*ilast-1
do p = 1,2*jlast-1
if (Mod(m,2) == 0) then
if (Mod(p,2) == 0) then
Hx(m-1,p+2) = Da*Hx(m-1,p+2)+Db*(Ez(m-1,p+2)-Ez(m-1,p+2))
Hy(m,p+1) = Da*Hy(m,p+1)+Db*(Ez(m+1,p+1)-Ez(m-1,p+1))
end if
end if
end do
end do
! set boundary condition
do m = 1,2*ilast-1
do p = 1, 2*jlast-1
if (p == 0) then
Ez(m,p) = 0
if (p == plast) then
Ez(1,p-1) = 0
Ez(mlast+1,p+1) = 0
end if
end if
end do
end do
close (unit=130)
end do !n
end SUBROUTINE fd2d
and i got this error msg:
Code:
subroutines.f90:120.15:
Ca(m,p) = 1.0
1
Error: Unexpected STATEMENT FUNCTION statement at (1)
subroutines.f90:121.33:
Cb(m,p) = deltat/(1-0.5*deltax)
1
Error: Unexpected STATEMENT FUNCTION statement at (1)
subroutines.f90:124.15:
Da(m,p) = 1.0
1
Error: Unexpected STATEMENT FUNCTION statement at (1)
subroutines.f90:125.25:
Db(m,p) = deltat/deltax
1
Error: Unexpected STATEMENT FUNCTION statement at (1)
i think my mistakes are from the array declaration of Ca,Cb, Da and Db....but I have no idea how to solve this. Can anyone tell me how to solve this....thank you very much |
