title: Error: unclassifiable statement in fortran in ux=cos(theta)sin(phi)
body: <p>I want to write a program in FORTRAN which calculate the detection efficiency for a punctual source  at a distance from the detector .The disc detector is assumed to be perfect: ie photon absorbing everything that falls on it. So here I am working in 3D and I use ux, uy and uz to lead the photon randomly using the spherical coordinate system;</p>
  
  <p>efficiency vs the detector radius</p>
  
  <p>Here is the bare code for punctual source: </p>
  
  <pre><code>program sourceponc
  
  integer i,N
  real  x,y,z,eff,count,Dds,rd,ux,uy,uz,t
  
  count=0
  do i=1,N
    theta = acos(1-2*rand())
    phi = 2*pi*rand()
    ux=cos(theta)sin(phi)
    uy=sin(theta)sin(phi)
    uz=cos(theta)
  
    t=Dds/uz
    x=ux*t
    y=uy*t
  
    if(sqrt(x**2+y**2+z**2).le.1)then
      count=count+1
    endif
  end do 
  
  eff=count/N
  print*,eff
  
  end
  </code></pre>
  
  <p>I keep getting these error while compiling:</p>
  
  <pre><code>sourceponc.f90:11:
  
  ux=cos(theta)sin(phi)
  1
  Error: Unclassifiable statement at (1)
  sourceponc.f90:12:
  
  uy=sin(theta)sin(phi)
  1
  Error: Unclassifiable statement at (1)
  </code></pre>
  
  <p>Can someone please help me with the following?</p>