[Fortran90] how to write several output into one file

[s_hy]

hi all,

Currently I am doing 2d fdtd (TMz mode) modeling. I expect to have output for Ez, Hx and Hy in one file, which is mean that the output will be in 3 column. But I don't have any idea how format it. Anyone can help me? Below is the 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
lambda = 1
 c = 1.0
E0 = 1.0
deltat = 1/sqrt(2.0)*(delta/c)
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
 do m = 1,2*ilast
  if (Mod(m,2) == 0) then
   if (Mod(p,2) == 0) then
      Hx(m-1,p+2) = 0
      Hy(m,p+1) = 0
      else
      Ez(m-1,p+1) = 0
   end if
  end if
 end do
end do

print*, 'see me?2'
!medium's properties
 Ca = 1.0
 Cb = deltat/(1-0.5*deltax)
 Print *,'Ca=',Ca,'Cb=',Cb
 Da = 1.0
 Db = deltat/deltax
 Print *, 'Da=',Da, 'Db=',Db

!initiate sinusoidal wavepulse at center

do n = 1,200
   
  write (filename, "('ez',I3.3,'.dat')") n
  open (unit=130,file=filename)
 
!initiate sinusoidal wavepulse at center
  Ez(101,101) = sin((n+1)*omega*deltat)
  
  do m = 2,2*ilast-1
    do p = 2,2*jlast-1
    
      if (Mod(m,2)/=0) then
	if (Mod(p,2)/=0) then
	  Ez(m,p+2) = Ca*Ez(m,p+2)+Cb*(Hy(m+1,p+2)-Hy(m-1,p+2)+Hx(m,p+1)-Hx(m,p+3))
          write (130,1) Ez(m,p+2)
          !print *, Ez(m,p+2)
        end if
      end if
    end do
  end do

  do m = 2,2*ilast-1
    do p = 2,2*jlast-1

      if (Mod(m,2) == 0) then
	if (Mod(p,2) == 0) then
	  Hy(m,p+1) = Da*Hy(m,p+1)+Db*(Ez(m+1,p+1)-Ez(m-1,p+1))
          Hx(m-1,p+2) = Da*Hx(m-1,p+2)+Db*(Ez(m-1,p+1)-Ez(m-1,p+3))
          write (130,1) Hx(m-1,p+2)
          write (130,1) Hy(m,p+1)
        end if
      end if
     end do
  end do

1 format (130(3E15.6))
  close (unit=130)

end do !n

end SUBROUTINE fd2d

Anyway, format I used to write file is not working.

Thank you

 

[AlephZero]

Each WRITE statement in Fortran starts a new line. To write three values on the same line you would do something like

write (130,1) Ez(m,p+2), Hx(m-1,p+2), Hy(m,p+1)

If might be easier to have a separate DO loop (or nested loops) for the write statement, after you have done all the calculations.

Also, your format statement should probably be just

1 format (3E15.6)

I'm not sure what you thought the "130" was for, but it actually means you could write 130 sets of three values all on one line, if you had one WRITE statement that output all 390 values. From yuor OP, that's not what you wanted to do.

 

[s_hy]

Thank you, alephzero.

I did as what you said and it's work! Btw, 130 is the filename, which I think will not effect the output.

 

[gsal]

Good.

By the way, Alephzero was talking about the 130 in your format statement:

1 format (130(3E15.6))
  close (unit=130)

that's a multiplier right there to write 130 times, 3 fields of 15.6.

 

[LudusRex]

for sharing your code and asking for help with formatting the output. It looks like you are trying to write data for Ez, Hx, and Hy into one file with three columns. To do this, you can use the "write" statement with the "advance" option set to "no" and the "fmt" option set to "(3E15.6)". This will write the data in three columns with a field width of 15 and a decimal precision of 6. Your code might look something like this:

do n = 1,200
write (filename, "('output.dat')") n
open (unit=130,file=filename)

!write Ez, Hx, and Hy data into one file
do m = 2,2*ilast-1
do p = 2,2*jlast-1
if (Mod(m,2)/=0) then
if (Mod(p,2)/=0) then
write (130, "(3E15.6)", advance="no") Ez(m,p+2), Hx(m-1,p+2), Hy(m,p+1)
end if
end if
end do
end do

close (unit=130)
end do

I hope this helps. If you continue to have trouble with formatting, I recommend consulting the documentation for Fortran90 or reaching out to a colleague or mentor for assistance. Good luck with your modeling!