optional graph database

[William Stein]

Hi,

This page of the Sage documentation talks about "the optional database
package containing all unlabeled graphs with 8 or fewer nodes.":

http://www.sagemath.org/doc/reference/graphs/sage/graphs/graph_database.html

But there is no optional graph database, or any optional/experimental
package of graphs at http://sagemath.org/packages/optional/ (etc.).

So.... any idea what happened to that spkg? Should the remarks about
a graph database be deleted from the documentation?



-- William


--
William Stein
Professor of Mathematics
University of Washington
http://wstein.org

[kcrisman]

On Wednesday, May 22, 2013 12:54:54 PM UTC-4, William wrote:

Hi,

This page of the Sage documentation talks about "the optional database
package containing all unlabeled graphs with 8 or fewer nodes.":

      http://www.sagemath.org/doc/reference/graphs/sage/graphs/graph_database.html

But there is no optional graph database, or any optional/experimental
package of graphs at http://sagemath.org/packages/optional/  (etc.).

So.... any idea what happened to that spkg?  Should the remarks about
a graph database be deleted from the documentation?

Presumably related: 

http://artsci.drake.edu/grout/doku.php/graph_database 

[Jason Grout]

On 5/22/13 12:36 PM, kcrisman wrote:
>
>
> On Wednesday, May 22, 2013 12:54:54 PM UTC-4, William wrote:
>
> Hi,
>
> This page of the Sage documentation talks about "the optional database
> package containing all unlabeled graphs with 8 or fewer nodes.":
>
> http://www.sagemath.org/doc/reference/graphs/sage/graphs/graph_database.html
> <http://www.sagemath.org/doc/reference/graphs/sage/graphs/graph_database.html>
>
>
> But there is no optional graph database, or any optional/experimental
> package of graphs at http://sagemath.org/packages/optional/
> <http://sagemath.org/packages/optional/> (etc.).
>
> So.... any idea what happened to that spkg? Should the remarks about
> a graph database be deleted from the documentation?
>
>

I'm not sure the optional spkg ever got made. The docs talk about the
spkg in the future tense. I think the short term the sentence should
just be deleted. I can put the SQL dump somewhere if someone wants to
package it up for an optional spkg.


>
> Presumably related:
>
> http://artsci.drake.edu/grout/doku.php/graph_database

Yes, that is the current URL for the data (8 or fewer vertices). The
docs should also be updated to reflect the new URL.

Thanks,

Jason

[Dima Pasechnik]

can't the optional package nauty be used instead? Surely it can generate all these graphs very quickly.

[Jason Grout]

On 5/23/13 12:34 AM, Dima Pasechnik wrote:
> can't the optional package nauty be used instead? Surely it can generate
> all these graphs very quickly.

Indeed, if all you are doing is generating the graphs, yes. The graph
database allows you to quickly query for graphs based on a number of
different cached parameter values, though. You could do a list
comprehension to calculate the parameters and discard the graphs you
don't want, but the convenience of a precomputed database sometimes is
what you want.

Thanks,

Jason

[Dima Pasechnik]

nauty (more precisely, geng) can do some of this on the fly :

Usage: geng [-cCmtfbd#D#] [-uygsnh] [-lvq] [-x#X#] n [mine[:maxe]]
[res/mod] [file]

Generate all graphs of a specified class.

n : the number of vertices
mine:maxe : a range for the number of edges
#:0 means '# or more' except in the case 0:0
res/mod : only generate subset res out of subsets 0..mod-1
-c : only write connected graphs
-C : only write biconnected graphs
-t : only generate triangle-free graphs
-f : only generate 4-cycle-free graphs
-b : only generate bipartite graphs
(-t, -f and -b can be used in any combination)
-m : save memory at the expense of time (only makes a
difference in the absence of -b, -t, -f and n <= 28).
-d# : a lower bound for the minimum degree
-D# : a upper bound for the maximum degree
-

perhaps having a nice Sage interface to this is better than bothering
with a database (which would be quite small too)

Dima

>
> Thanks,
>
> Jason
>

[mmarco]

From what i see in the nauty web page, its license is not GPL
compatible, since it forbids sale for profit or application with
nontrivial military significance.

I guess that's the reason why it is not included as a standard
package, right?

On 23 mayo, 08:00, Dima Pasechnik <dimp...@gmail.com> wrote:

[Volker Braun]

On Thursday, May 23, 2013 11:14:27 AM UTC+1, mmarco wrote:

I guess that's the reason why it is not included as a standard
package, right?

Yes.