graphs: Strongly regular graph database

[jason]

From Chris Godsil's wishlist:

> 
>>> A database of small graphs. Put Ted Spence's strongly regular graphs
>>> into a
>>> database. (In this case the important thing is to have the graphs
>>> themselves,
>>> we would not necessarily need much data.)

[mvngu]

CC'ing myself

[ncohen]

If it just consists in converting the 32,548 graphs with parameters (36-15-6-6) to some database, I could do that with a bit of scripting... I saw there was in SAGE_DATA a file graphs.db ( sqlite format ), and the trouble is that I do not know what it contains, how to open it, and how to build one myself if it is what you expect... Could I know a bit more about this ? :-)

[jason]

I believe that database just contains the data that is exposed here:

 http://good.math.iastate.edu/grout/graphs/

You can download one of the many SQLITE GUI tools listed at  http://www.sqlite.org/cvstrac/wiki?p=ManagementTools and look at the database.

[ncohen]

Thank you !!! I understand how it works now :-)

Well, so what about this database ? Do you think it would be a good idea to build a sqlite database for Sage with these graphs ? I do not know, for example, if this database will be compressed in any way, because there are a lot of graphs available and it could become a bit heavy.. Is there anything more efficient, in case the users needs to enumerate them all ?

[jason]

Here is a worksheet showing how to convert the graphs on Ted's page to Sage graphs:  http://test.sagenb.org/home/pub/17/