Re: [Help-glpk] Ramsey, GLPK, chrestomathy

[Nigel Galloway]

Andrew,

As always I am at your command sometimes, see
http://rosettacode.org/wiki/Ramsey.

The impressive thing is that glpk can find a solution in 3 seconds.

I had written some code in C++ to get an idea of the problem. Initially
I tried cutting the graph into subgraphs of 6 solving those and then
trying to combine them. I then started with 6 and tried adding a
seventh, eigth etc to get some idea of the shape of this distribution.
It rises in a manner that makes exponential seem gentle, peaks and then
falls of a cliff with solutions very rare. The latter I simply
tranferred into mathprog with scalar variables.

-- 
  Nigel Galloway
  address@hidden


On Tue, Jan 17, 2012, at 08:28 PM, Andrew Makhorin wrote:
> Hi Nigel,
> 
> > Chrestomathy is my word for 2012. Don't worry I don't know what it
> > means, looks like it may have escaped from Greek and is seeking refuge
> > in English. http://rosettacode.org/wiki/Rosetta_Code is an example.
> > Until 2011 it knew 424 langages. I've made that 425 by adding Mathprog:
> > see http://rosettacode.org/wiki/Category:Mathprog
> > 
> > I added a new Task for Mathprog to solve see
> > http://rosettacode.org/wiki/Ramsey
> > 
> > I added the problem in Mathprog see
> > http://rosettacode.org/wiki/Execute_Ramsey_Mathprog
> > 
> > and the solution see
> > http://rosettacode.org/wiki/Solution_Ramsey_Mathprog
> > 
> 
> Thank you for your information.
> 
> I noticed that the MathProg model uses scalar variables and constraints
> that makes it difficult to read. Why not to use indexed objects?
> 
> 
> Andrew Makhorin
> 
> 

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