pulse.f

a 2-d FDTD program using PML

*--------------------------------------------------------------------*
      real function pulse(i,j)
      include 'xfdtmcom.f'
      if ( (i.eq.imid).and.(j.eq.jmid) ) then
         arg=t/(20.*dt)
         if(arg.le.1.)then
           pulse = (sin(2.*pi*arg - pi/2) + 1.)/2.
         else
           pulse = 0.
         endif
      else
         pulse=0.
      endif
      return
      end