Hello everybody ! I come back again with a problem that was forgotten but never solved. It is FindStat related.
1) here are two functions in Sage named Poset.to_graph and Graph.to_partition. Those two functions have a common point: their name is rather vague. Poset.to_graph) There are three graphs that I know which can be associated to a Poset. Its comparability graph [1], its incomparability graph, and the undirected version of its Hasse Diagram [2]. When I see "Poset.to_graph" I cannot guess which one it may be. Turns out that P.to_graph is actually Graph(P.hasse_diagram()) or P.hasse_diagram().to_undirected() which is rather explicit. Graph.to_partition) There are 1000 different partitions that can be associated to a Graph. In fact, I could describe the work of most researchers I know as "an attempt to compute a partition of a graph". In this specific situation, the function Graph.to_partition returns the partition associated to the sizes of the connected components of the graph. You can obtain it with Partition(sorted(map(len,G.connected_components()),reverse=True)). I cannot emphasize sufficiently that no researcher in graph theory will never associate "partition" to "partition of an integer". When we talk about a partition, we talk about a partition of the vertex set. 2) What about those functions ? Both could be renamed to have more meaningful names. This being said, I would not see the point of a Poset.hasse_diagram_undirected() or Poset.undirected_hasse_diagram() when it can already be obtained as Graph(Poset.hasse_diagram()). Graph.to_partition could be renamed to Graph.connected_components_sizes_partition. Indeed, we already have: - Graph.connected_component_containing_vertex - Graph.connected_components - Graph.connected_components_number - Graph.connected_components_subgraphs and so this function could join them. I would personally prefer to have this function removed too: to me this function should be implemented in FindStat [3] and is not useful to us. Nathann [1] http://www.sagemath.org/doc/reference/graphs/sage/graphs/comparability.html [2] the "undirected version of the transitive closure of its hasse diagram" is equal to the comparability graph. [3] http://www.findstat.org/ -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
