i am looking to implement a algorithm for the Travel Salesman Problem. I want to model the solution using the graph , in this a vertex will represent a city and edge will represent the cost from one city to another.
At any point i have to compute cost from one city to another like
(cityA, cityB)--->cost
What data structure in java should i use for graph?
And what kind of GUI tool or library can i use to represent a graph ?
If you are free to use external libraries, JGraphT is easy to use.
Why a graph, of course. Take a look at JUNG.
depending on the size of your problem and your hardware, you might want to take a look at nosql graph databases like: http://neo4j.org/
most of them are easy to handle and some (like neo4j) provide a graph visualization which is nice for debugging purpose.
if you want to develop with as much performance as possible, you might have to create your own simple graph format. Most of the told ones are slow due to a lot of overhead (generics etc.)
Can anyone recommend a Java Graph Visualisation library in which graph nodes can be rendered with multiple connect points?
For example, supposing a graph node represents a processor that takes input from two sources and produces output. This would be visualised as 3 vertices. However, clearly each vertex has a defined role in the workflow and therefore ideally my node would appear with 3 distinct connection points that the user could attach vertices to.
I've taken a look at JUNG but I don't think it will suit my needs.
Any recommendations welcome; either on specific libraries or alternative approaches I can take.
You could try JGraph's java library
JGRAPH
It has a good amount of functionality and I have used it with success before. The only thing is that the documentation is a bit lacking, but if you read through some examples and code its pretty good when you get the hang of it.
Take a look at JGraph (http://www.jgraph.com/). I used jgraph-5.14.0.0 for a similar project before. Here are the graphs that I made for another project: https://github.com/eamocanu/spellcheck.graph/tree/master/graph%20photos
I would like to use the concept of MindMap
http://en.wikipedia.org/wiki/Mind_map
in a AI program. Is there any API for java? A good api for drawing and manipulating graphs with enough documentation and examples will also do the job.
I dont actually need to represent it graphically , i just need to build the map in any method(used for representing graphs, ) and search in it.
The program shall take a word as input
Search the mindmap for it and display the relevant words.
JGraphT was possible solution for me. I am working on it
Have you tried FreeMind? It's an open-source Java MindMap framework.
Is there a Graph generation library in Java which generators graphs (of different types) such that
G{n,p} graph chooses each of the possible [n(n-1)]/2 edges with probability p.
The closest I could find was NetworkX -Python package for the creation, manipulation, and study of the structure, dynamics, and functions of complex networks.
Well If I cant find anything good I might have to create my own random generator using jGraph or jgraphT
http://jung.sourceforge.net/
i hope it helps
Well nevermind
I just used JgraphT to write a function which adds edges based on a probability p for each edge.
There are several such generators in gephi: Erdős–Rényi by default, and many others through additional plugins (Barabasi-Albert, Watts-Strogatz...).
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Has anyone had good experiences with any Java libraries for Graph algorithms. I've tried JGraph and found it ok, and there are a lot of different ones in google. Are there any that people are actually using successfully in production code or would recommend?
To clarify, I'm not looking for a library that produces graphs/charts, I'm looking for one that helps with Graph algorithms, eg minimum spanning tree, Kruskal's algorithm Nodes, Edges, etc. Ideally one with some good algorithms/data structures in a nice Java OO API.
If you were using JGraph, you should give a try to JGraphT which is designed for algorithms. One of its features is visualization using the JGraph library. It's still developed, but pretty stable. I analyzed the complexity of JGraphT algorithms some time ago. Some of them aren't the quickest, but if you're going to implement them on your own and need to display your graph, then it might be the best choice. I really liked using its API, when I quickly had to write an app that was working on graph and displaying it later.
Summary:
JGraphT if you are more interested in data structures and algorithms.
JGraph if your primary focus is visualization.
Jung, yWorks, and BFG are other things people tried using.
Prefuse is a no no since one has to rewrite most of it.
Google Guava if you need good datastructures only.
Apache Commons Graph. Currently dormant, but provides implementations for many algorithms. See https://issues.apache.org/jira/browse/SANDBOX-458 for a list of implemented algorithms, also compared with Jung, GraphT, Prefuse, jBPT
Check out JGraphT for a very simple and powerful Java graph library that is pretty well done and, to allay any confusion, is different than JGraph. Some sample code:
UndirectedGraph<String, DefaultEdge> g =
new SimpleGraph<String, DefaultEdge>(DefaultEdge.class);
String v1 = "v1";
String v2 = "v2";
String v3 = "v3";
String v4 = "v4";
// add the vertices
g.addVertex(v1);
g.addVertex(v2);
g.addVertex(v3);
g.addVertex(v4);
// add edges to create a circuit
g.addEdge(v1, v2);
g.addEdge(v2, v3);
g.addEdge(v3, v4);
g.addEdge(v4, v1);
JUNG is a good option for visualisation, and also has a fairly good set of available graph algorithms, including several different mechanisms for random graph creation, rewiring, etc. I've also found it to be generally fairly easy to extend and adapt where necessary.
Apache Commons offers commons-graph. Under http://svn.apache.org/viewvc/commons/sandbox/graph/trunk/ one can inspect the source. Sample API usage is in the SVN, too. See https://issues.apache.org/jira/browse/SANDBOX-458 for a list of implemented algorithms, also compared with Jung, GraphT, Prefuse, jBPT
Google Guava if you need good datastructures only.
JGraphT is a graph library with many Algorithms implemented and having (in my oppinion) a good graph model. Helloworld Example. License: LGPL+EPL.
JUNG2 is also a BSD-licensed library with the data structure similar to JGraphT. It offers layouting algorithms, which are currently missing in JGraphT. The most recent commit is from 2010 and packages hep.aida.* are LGPL (via the colt library, which is imported by JUNG). This prevents JUNG from being used in projects under the umbrella of ASF and ESF. Maybe one should use the github fork and remove that dependency. Commit f4ca0cd is mirroring the last CVS commit. The current commits seem to remove visualization functionality. Commit d0fb491c adds a .gitignore.
Prefuse stores the graphs using a matrix structure, which is not memory efficient for sparse graphs. License: BSD
Eclipse Zest has built in graph layout algorithms, which can be used independently of SWT. See org.eclipse.zest.layouts.algorithms. The graph structure used is the one of Eclipse Draw2d, where Nodes are explicit objects and not injected via Generics (as it happens in Apache Commons Graph, JGraphT, and JUNG2).
http://neo4j.org/ is a graph database that contains many of graph algorithms and scales better than most in-memory libraries.
In a university project I toyed around with yFiles by yWorks and found it had pretty good API.
check out Blueprints:
Blueprints is a collection of interfaces, implementations, ouplementations, and test suites for the property graph data model. Blueprints is analogous to the JDBC, but for graph databases. Within the TinkerPop open source software stack, Blueprints serves as the foundational technology for:
Pipes: A lazy, data flow framework
Gremlin: A graph traversal language
Frames: An object-to-graph mapper
Furnace: A graph algorithms package
Rexster: A graph server
http://incubator.apache.org/hama/ is a distributed scientific package on Hadoop for massive matrix and graph data.
JDSL (Data Structures Library in Java) should be good enough if you're into graph algorithms - http://www.cs.brown.edu/cgc/jdsl/
For visualization our group had some success with prefuse. We extended it to handle architectural floorplates and bubble diagraming, and it didn't complain too much. They have a new Flex toolkit out too called Flare that uses a very similar API.
UPDATE:
I'd have to agree with the comment, we ended up writing a lot of custom functionality/working around prefuse limitations. I can't say that starting from scratch would have been better though as we were able to demonstrate progress from day 1 by using prefuse. On the other hand if we were doing a second implementation of the same stuff, I might skip prefuse since we'd understand the requirements a lot better.
Try Annas its an open source graph package which is easy to get to grips with
http://annas.googlecode.com
It's also good to be convinced that a Graph can be represented as simply as :
class Node {
int value;
List<Node> adj;
}
and implement most the algorithms you find interesting by yourself. If you fall on this question in the middle of some practice/learning session on graphs, that's the best lib to consider. ;)
You can also prefer adjacency matrix for most common algorithms :
class SparseGraph {
int[] nodeValues;
List<Integer>[] edges;
}
or a matrix for some operations :
class DenseGraph {
int[] nodeValues;
int[][] edges;
}
I don't know if I'd call it production-ready, but there's jGABL.
If you need performance, you might take a look at Grph. The library is developed in the French University and CNRS/Inria.
http://www.i3s.unice.fr/~hogie/grph/
The project is active and reactive support is provided!
Instructional graph algorithm implementations in java could be found here (by prof. Sedgewick et al.):
http://algs4.cs.princeton.edu/code/
I was introduced to them while attending these exceptional algorithm courses on coursera (also taught by prof. Sedgewick):
https://www.coursera.org/course/algs4partI
https://www.coursera.org/course/algs4partII
If you are actually looking for Charting libraries and not for Node/Edge Graph libraries I would suggest splurging on Big Faceless Graph library (BFG). It's way easier to use than JFreeChart, looks nicer, runs faster, has more output options, really no comparison.
JGraph from http://mmengineer.blogspot.com/2009/10/java-graph-floyd-class.html
Provides a powerfull software to work with graphs (direct or undirect). Also generates Graphivz code, you can see graphics representations. You can put your own code algorithms into pakage, for example: backtracking code. The package provide some algorithms: Dijkstra, backtracking minimun path cost, ect..