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Breakdown of the X!Tandem, X!!Tandem, and Duncan methods, showing the time spent in each step. Steps that are too small to see are omitted. X!Tandem and X!!Tandem methods break down into unrefined and refined search steps, each followed by a communication/merge step. The Duncan method is quite different, consisting of 3 separate steps requiring invocations of X!Tandem, separated by runs of utility programs. The dotted line represents sequential X!Tandem runtime.
