Graph Analysis and Drawing Library - Grad

Site: http://www.gradlibrary.net

Javadoc: https://renatav.github.io/GraphDrawing/

Grad is a library for the Java programming language whose main goals are to provide a large number of graph drawing and analysis algorithms and a very simple integration with existing tools. It consists of three projects:

• GraphDrawingTheory - the core of the library, containing numerous algorithms
• GraphEditor - a simple graph editor that can be used to test the layout and anaylisis features
• GraphLayoutDSL - defines a domain-specific language (DSL) for specifying how a graph should be laid out

Implemented analysis algorithms

Grad offers implementations of several noteable graph analysis algorithms.

Graph traversal

• Dijkstra's shortest path
• Depth-first search and construction of DFS trees

Graph connectivity

• Checking connectivity, biconnectivity and triconnectivity of graphs
• Finding graph cut vertices and blocks (biconnected components) of a graph
• Hopcroft-Tarjan division of a graph into triconnected components
• Construction of BC (block-cut vertex) trees
• Construction of SPQR trees (not thoroughly teseted yet)
• Planar augmentation - an algorithm for turning a connected graph into a biconnected one. Based on Fialko and Mutzel's 5/3 approximation algorithm

Cyclic properties

• Johnson's algorithms for finding simple cycles of a directed graph
• Paton's algorithm for finding cycles of an undirected graph

Planarity testing

• Fraysseix-Mendez planarity testing
• Boyer-Myrvold planarity testing which finds the outside face
• PQ tree planarity testing with Booth and Lueker's algorithm, which finds the upwards embedding
• Finding an embedding and planar faces given an upwards embedding

Graph symmetry

• McKay's canonical graph labeling algorithm (nauty) for finding permutations
• De Fraysseix's heuristic for graph symmetry detection
• Analyzing permutations and finding permtuation groups
• Forming permutation cycles

Other

• Checking if a graph is bipartite
• Checking if a tree is binary
• Finding topological ordering
• Finding st-ordering

Layout algorithms

Grad has several original implementaions of different graph drawing (layout) algorithms and ports some excellet implementations form other open-soucce libraries. It strives to provide a very easy way of calling any desired algorithm.

Original implementations

• Box layout (simple positioning of graph vertices into a table-like structure)
• Circle layout with or without the optimization of edge crossings
• Tutte straight-line drawing
• Concentric symmetric drawing based on Car and Kocay's algorithm
• Chiba's convex drawing of planar graphs
• Work in progress: orthogonal drawing

Ported algorithms

• Lebel-based tree drawing
• Tree balloon layout
• Node link tree layout
• Radial tree layout
• Hierarchical layout
• Spring, Kamada-Kawai and force-dircted layout
• Organic and fast-organic layouts
• ISOM layout