Function to create a tgraph representation of a hierarchically organised dataframe. This is the focal object of the t* functions - the complete set of hierarchical relationships between a set of elements
tgraph(x, ranks = NULL, verbose = TRUE)
a tgraph object
A dataframe containing a set of hierarchical relationships. The leftmost column contains the elements which will form the highest rank, followed rightwards by successive ranks
If not NULL, a vector of column names of x, given in rank order. This is useful if x contains columns which are not rank relevant or if columns are not in hierarchical order. If not supplied, the column order in x is used directly and is assumed to be in rank order
A logical indicating whether the progress of tgraph construction should be reported to the console