PIGALE Images

P.I.G.A.L.E.

Public Implementation of a Graph Algorithm
Library and Editor

H. de Fraysseix P. Ossona de Mendez

A Quick Tour

Representation of a planar graph by contacts of T's

>

Representation of a bipartite planar graph by contacts of segments

Different representations of the same planar graph:

Tutte drawing	Spring embedder
	>

Drawing on a small grid with polylines	Drawing with B�ier curves

Drawings based on visibility representations (planar and non-planar)

Convex Drawings (compact or not)

Finding a cotree citrical or a Kuratowski subgraph

Non planar graph	Cotree critical subgraph	Kuratowski subgraph

Heuristic to extract a planar subgraph

Embedding a graph in R^n-1

Pigale can compute different embeddings of a graph in R^n-1. The user can choose the projection to display.

thumbs/sydney.png

thumbs/capture02.png

thumbs/sydneyc.png

thumbs/sydneyb.png

Embedding a cube in R^n-1 using different distances

Czekanovski-Dice	Translated adjacency	Laplacian

Partitioning a graph

Two examples of the partitioning algorithm which uses an embedding of the graph in R^n-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 R^n-1.

thumbs/syma.png

thumbs/symb.png

thumbs/symfac.png

thumbs/symspace35a.png

thumbs/symspacea.png

Hubert de Fraysseix

Patrice Ossona de Mendez

Last modified: Tue Jan 29 12:02:43 CET 2008