Re: [Bug-gnubg] Is GNUBG actively developed?

[Philippe Michel]

On Mon, 14 Jan 2013, Mark Higgins wrote:

> What training approach have you been using, if you don't mind elaborating?

Supervised training. I used the same training tools that were used years 
ago to create the current nets.

The main difference is that I rolled out the training database while it 
previously used (as far as I know) 2ply evaluations from the preceding 
generation of nets.

This obviously took some time, but with current processors what was out of 
question in the early- to mid-2000s when the currents nets were trained is 
now doable.

I don't know if Joseph Heled did many iterations (reevaluate database / 
train nets / maybe add mishandled positions) but with rollouts, each of 
them take a long time (I did it twice for the crashed database and once 
for the contact one). This is then mostly a one-shot effort, at least 
until something important changes in the training database.

Another thing that must have been helpful is that I added to the trainig 
databases its positions with the other player on roll. I think this helped 
a little for the general playing strength and diminished significantly the 
odd/even plies discrepancies.

I used slightly larger pruning nets, with sizes adapted to SSE or AVX 
instructions, but I don't think it make much of a difference.