vocabulary V1 {
  extern vocabulary V
  SourceOf(Variant): Manuscript
}

theory T1 : V1 {
  ! x : (x ~= SourceOf(VariantOf(x))) => ? y : CopiedBy(y,x) & VariantOf(y) = VariantOf(x).
}

procedure check(sample) {
  stdoptions.groundwithbounds=false
  stdoptions.symmetrybreaking="static"
  idpintern.setvocabulary(sample,V1)
  return onemodel(T1,sample)
}

procedure findGroupings(samples) {
  local result = {}
  for _,sample in ipairs(samples) do
  -- Find out whether the sample fits the stemma.
    local model = check(sample)
    if model then
      table.insert(result,{ getGrouping(model), true })
    else
      table.insert(result,{ getGrouping(sample), false })
    end
  end
  return result
}

procedure getGrouping(model) {
  local grouping = {}
  for tuple in tuples(model[V::VariantOf].graph.ct) do
    local manuscript, variant = tuple[1], tuple[2]
    if grouping[variant] == nil then 
      grouping[variant] = {manuscript}
    else
      table.insert(grouping[variant],manuscript)
    end
  end
  return grouping
}