# This is the new part: We declare that there will
# be two compositional fields that will be
# advected along. Their initial conditions are given by
# a function that is one for the lowermost 0.2 height
# units of the domain and zero otherwise in the first case,
# and one in the top most 0.2 height units in the latter.
subsection Compositional fields
  set Number of fields = 2
end

subsection Initial composition model
  set Model name = function

  subsection Function
    set Variable names      = x,y
    set Function expression = if(y<0.2, 1, 0) ; if(y>0.8, 1, 0)
  end
end
