Dear Prof. Johnson, I'm not the developer of the R interface but I thought I'd answer anyway and let Gabor correct or extend what I say.
> 1. I need to have relatively complicated R objects that are > represented by the igraph nodes. For example, a variable may be it > 'ordinary' format X, or it may be log(x), or poly(x,d), or so forth. > I'm thinking of still calling it X in the graph, but there would be > some right-click magic to allow the user to ask for transformations. > Is it feasible to add more variables inside a node object. Possible? > Can you point me at the right starting point or example? Internally, igraph treats the nodes as integers, but it allows you to attach arbitrary R objects as attributes to the nodes (and also to the edges). So, you can probably store all the extra information you need in an appropriately constructed R data type and then attach this to the node as a "data" attribute or something like that. For instance, suppose that you want to store the "type" of a node and the type is one of "ordinary", "log" or "exp". You can then do something like this: V(g)$type <- "ordinary" # assigns "ordinary" to the type of each node V(g)[2]$type <- "exp" # sets the type of node 2 to "exp" V(g)$type # returns the types of each vertex As for the right-click magic: tkplot does not allow the customization of the vertex popup menu yet, but it is probably not too difficult by taking the source code of tkplot() as a template, copying it, and then modifying it as needed (look for the lines starting with tkadd(vertex.popup.menu…)). > 2. Suppose a graph exists, and I view and re-arrange it with tkrplot. > > Is there a way to make the re-arranged objects take notice of the > changes so that they are recorded permanently. Again, this can be achieved by modifying the tkplot() function. tkplot() attaches event handlers to several mouse events of the drawing canvas; for instance, the line starting with tkitembind(canvas, tobind, "<B1-Motion>", …) attaches an event handler to the "<B1-Motion>" event, which is fired when the user moves the mouse while button 1 of the mouse is pressed. This corresponds to moving the selected vertices. Adding your own code into the body of the event handler function allows you to respond to the re-arrangement of the nodes. Note that tkplot() does not support adding new vertices/edges or removing existing ones (as far as I know), so if the re-arrangements you wish to perform on the graphical representation of the models includes adding/removing vertices or edges, then this definitely needs more coding. All the best, Tamas _______________________________________________ igraph-help mailing list igraph-help@nongnu.org https://lists.nongnu.org/mailman/listinfo/igraph-help
