title: Unclassifiable statement at (1) fortran
body: <p>At line 99, the formula of <code>gsurf(iel)</code> is giving me the error: </p>
  
  <pre><code>unclassifiable statement at (1)
  </code></pre>
  
  <p>where the one is at the beginning of line 99 when compiling the program. Any suggestions on how to solve this problem?</p>
  
  <pre><code>program gravity
  
  implicit none
  real(8) Lx,Ly,sx,sy,xsphere,ysphere,r,A,rho1,rho2,dx,G1
  integer np,nel,nelx,nely,i,nnx,nny,j,counter,nsurf,iel
  real(8),dimension(:),allocatable :: xcgrid
  real(8),dimension(:),allocatable :: ycgrid
  real(8),dimension(:),allocatable :: xgrid
  real(8),dimension(:),allocatable :: ygrid
  real(8),dimension(:),allocatable :: rho
  real(8),dimension(:),allocatable :: xsurf
  real(8),dimension(:),allocatable :: ysurf
  real(8),dimension(:),allocatable :: gsurf
  
  nnx=101.
  nny=101.
  Lx=100.
  Ly=100.
  nelx=nnx-1.
  nely=nny-1.
  nel=nelx*nely
  np=nnx*nny
  sx=Lx/nelx
  sy=Ly/nely
  xsphere=50.
  ysphere=50.
  r=12.
  nsurf=7  !number of gravimeters
  G1=6.6738480*10**(-11) !m^3 kg^-1 s^-2
  
  dx=Lx/(nsurf-1.)
  
  !==========================================================
  
  allocate(xgrid(np))
  allocate(ygrid(np))
  
  counter=0
  do i=1,nnx
      do j=1,nny
      counter=counter+1   
      xgrid(counter)=dble(i-1)*sx
      ygrid(counter)=dble(j-1)*sy
      end do
  end do
  
  call write_two_columns(np,xgrid,ygrid,'grid_init.dat')
  !==========================================================
  
  allocate(xcgrid(np))
  allocate(ycgrid(np))
  
  
  counter=0
  do i=1,nnx-1
      do j=1,nny-1
      counter=counter+1   
      xcgrid(counter)=dble(i-1)*sx+0.5*sx
      ycgrid(counter)=dble(j-1)*sy+0.5*sy
      end do
  end do
  
  call write_two_columns(np,xcgrid,ycgrid,'gridc_init.dat')
  !==========================================================
  
  allocate(rho(nel))
  
  rho1=3000. !kg/m^3
  rho2=3200. !kg/m^3
  
  do i=1,nel  
      if (sqrt((xsphere-xcgrid(i))**2)+((ysphere-ycgrid(i))**2)&lt;r) then
      rho(i)=3200.
      else 
      rho(i)=3000.
      end if
  end do
  
  
  call write_three_columns(nel,xcgrid,ycgrid,rho,'inclusion.dat')
  !==========================================================
  
  allocate(xsurf(nsurf))
  allocate(ysurf(nsurf))
  
  do i=1,nsurf
  xsurf(i)=(i-1)*dx
  ysurf(i)=ly
  end do
  
  call write_two_columns(nsurf,xsurf,ysurf,'surf_init.dat')
  !==========================================================
  
  allocate(gsurf(nel))
  
  do i=1,nsurf
  xsurf(i)=(i-1)*dx
  ysurf(i)=ly
      do iel=1,nel
      gsurf(iel)=2.*G1*(((rho(iel)-rho1)*(y(iel)-ygrid))/((x(iel)-xgrid)**2.+(y(iel)-ygrid))**2.)))*sx*sy
      end do
  end do
  
  call write_two_columns (nel,ysurf,xsurf,gsurf,'gravity.dat')
  
  deallocate(xgrid)
  deallocate(ygrid)
  deallocate(xcgrid)
  deallocate(ycgrid)
  deallocate(xsurf)
  deallocate(ysurf)
  
  end program"
  </code></pre>