# Where on the internet I can find database of graphs?

I am studying graph algorithms.

I need database of graphs on which I can test my algorithms.

Where can I find reliable database of graphs of all kinds?

Thanks!

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You might want to be more specific. Do you want all graphs on $n$ vertices or less? Do you want pathological examples? How do you want your graphs presented to you? Graphically? An edge list? As an input to a specific piece of software. SAGE has large classes of graphs built-in. – Cam McLeman May 6 '10 at 17:42
One option is to generate random graphs -- the usefulness of this would depend on the specific application in mind. – Douglas S. Stones May 7 '10 at 1:41

## 7 Answers

You might want to look at Donald Knuth's Stanford GraphBase: A Platform for Combinatorial Computing (1994, 2009) and the accompanying website.

See also The Stony Brook Algorithm Repository.

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There's a nice collection of data on regular graphs at Markus Meringer's webpage.

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Sage (http://www.sagemath.org/) provides access to a large collection of graphs, as well as tools for working with them.

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nauty comes with some additional programs. In particular, you might be interested in geng. As the website says "geng can generate non-isomorphic graphs very quickly. There are also generators for bipartite graphs, digraphs, and multigraphs."

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Maple 13 or newer has a GraphTheory package that has a graph generator which allows you to generate all non-isomorphic graphs satisfying various criteria. You can use that to produce graphs and export them in various formats. In addition, you can produce random graphs using this package.

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Here's a collection of 3054 "standard named graphs" from Mathematica's GraphData collection http://yaroslavvb.com/upload/graphs2.txt

It's one graph per line, description followed by pairs of adjacent vertices

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Two such websites I am aware of are:

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