Either a variable name for the graph, given as a character string. (If it is not a syntactically valid name, make.names is called to change it to a valid one.)
Or an object of class
grid
Positive integer that sets the grid size for easier placement of nodes.
debug
Logical. If TRUE debug output is printed to the R console.
Value
The function itself returns NULL. But with the GUI a graph can be created or edited that will be available in R under the specified variable name after saving.
Details
See the vignette of this package for further details, since describing a GUI interface is better done with a lot of nice pictures.