ISGCI in Sage (a Graph Classes database http://www.graphclasses.org/ )

[ncohen]

This ticket creates a file

sage/graphs/isgci.py

That is a first implementation of an interface between Sage and the Graph Classes database ISGCI ![1]. With this interface, the XML content of the database can be read using dictionaries and lists (much easier to work with), and some operations are implemented like the comparison (relatively to inclusion) of graph classes.

There will be more work needed on this new feature, for instance the implementation of an easy way to query the database.

Along with the patch, two .sobj files should be added to the directory $SAGE_ROOT/data/graphs/. These files are an .sobj version of the database that I created on my own computer.

When this patch will be merged into Sage, it is likely that users that do not update their version of Sage will progressively then be working with an outdated version of the database, as the version will be the one used the day they downloaded their copy of Sage. To avoid that, this patch implements a function sage.graphs.isgci.update_db() that downloads a new version of the database from ISGCI's website and updates the current .sobj files.

Hence, instead of using my two files attached to this ticket, one can also call this method which will create them automatically.

I tried to make the documentation clear enough about all that is currently possible with ISGCI.

One of the discussions on sage-devel related to this database: ​http://groups.google.com/forum/#!searchin/sage-devel/This$20is$20the$20copy$20of$20several$20mails$20concerning$20ISGCI$20and$20what$20we$20could$20do$20with/sage-devel/N05a9w_UrIA/XGlVD7NT7p4J

Nathann

![1] ​http://www.graphclasses.org/

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Apply trac_11880.patch​ to the Sage library.