data-flow.dot

digraph {
  subgraph cluster_os {
    label = "Operating System"

    node [shape = box]
    null [label = "Null Device"]
    xlsr [label = "Excel File"]
    csvr [label = "Value File"]
    csvw [label = "Value File"]

    node [shape = oval]
    gnumeric [label = "Gnumeric"]

    subgraph cluster_tmvs {
      label = "TMVS"

      subgraph cluster_ws {
        label = "Working Set"

        node [shape = box]
        aggr [label = "Aggregate"]
        interp [label = "Interpolator"]
        plot [label = "Plot"]

        node [shape = oval]
        import [label = "Import"]
        export [label = "Export"]
        merge [label = "Merge"]
        interpolate [label = "Interpolate"]
        discretize [label = "Discretize"]
        draw [label = "Draw"]
      }

      subgraph cluster_cache {
        label = "Cache"

        node [shape = box]
        cache [label = "Cache File"]

        node [shape = oval]
        store [label = "Store"]
        recall [label = "Recall"]
        fetch [label = "Fetch"]
        purge [label = "Purge"]
      }
    }
  }

  xlsr -> gnumeric -> csvr
  csvr -> import -> aggr
  aggr -> export -> csvw
  aggr -> merge -> aggr
  aggr -> interpolate -> interp
  interp -> discretize -> aggr
  aggr -> draw -> plot
  aggr -> store -> cache
  cache -> recall -> aggr
  csvr -> fetch -> aggr
  cache -> fetch -> cache
  null -> purge -> cache

  fetch -> import [style = invis]
  recall -> import [style = invis]
}