logo P.I.G.A.L.E.
(Qt version)

Public Implementation of a Graph Algorithm Library and Editor
H. de Fraysseix, P. Ossona de Mendez
hf @ ehess.fr

A Quick Tour

Forcing a graph on a grid

One can force the vertices of a graph to be on a given grid, as long as it does not create overlapping vertices and that the genus is not modified.
thumbs/grille.png thumbs/grillea.png

Tutte drawing

It is a modified Tutte drawing, which gives better results that our former spring embedder.
thumbs/capture09.png thumbs/capture10.png thumbs/capture05.png thumbs/capture05a.png

Finding a maximal planar subgraph

This heuristic gives reasonable results for quasi planar graphs: the blue edges are the ones detected by the algorithm.
thumbs/capture03.png thumbs/capture04.png

Embedding a graph in Rn-1

Pigale can compute different embeddings of a graph in Rn-1. The user can choose the projection to display.
thumbs/sydney.png thumbs/capture02.png thumbs/sydneyc.png thumbs/sydneyb.png

Partitioning a graph

The partitioning of the graph uses an embedding of the graph in Rn-1.
thumbs/capture01.png thumbs/capture01a.png thumbs/sydneycuta.png thumbs/sydneycuta1.png

Finding symmetries

The automorphisms of a graph are in bijection with its isometries for a suitable embedding in Rn-1.
thumbs/syma.png thumbs/symb.png thumbs/symfac.png thumbs/symspace35a.png thumbs/symspacea.png

Last modified: Tue Apr 9 10:52:22 CEST 2002