A list of character elements containing the name of
the nodes for which the distribution is to be plotted. Default is
NULL, and plots the distribution for each node.
nodesPerCol
an integer specifying the number of plots to be
displayed per column when plotting multiple nodes at once. Default is
NULL.
nodesPerRow
an integer specifying the number of plots to be
displayed per row when plotting multiple nodes at once. Default is
NULL.