RE: bug

[Ian Shaw]

Hi Armin,

7-ply is a huge search space. It has to evaluate my opponent's next four rolls 
and cube decision, and my next three rolls after the current position, too. 
Each of these has 21 different dice combinations and many ways to play each 
roll. Maybe gnubg is not hanging, but was still calculating when you ran out of 
patience! Did you try the red Stop button in the bottom-right corner?

You have a 3.5 GHz chip. Mine is nearly as fast (i7 3.4 GHz), and I've never 
tried a 7 ply evaluation, even on a simple position. On a complex position with 
many choices, the evaluation could take a very long time. I asked for a 7-ply 
evaluation of an opening roll 43 when I started this reply, and it's still 
calculating, three hours later.

If I remember correctly, evaluation doesn't use multiple threads so you don't 
get full use from your fancy CPU, but rollouts will multi-thread. 

I would suggest that a rollout might be a better use of your computer 
resources, because it will take advantage of the 8 core processor you have. Go 
to Settings, Options, Other and set Eval Threads to 16 (or fewer, if you want 
to save some for other tasks). I also recommend that you go to the command line 
and type "set priority idle" so that gnubg only uses cores when they are not in 
use for other things. This stops your computer slowing down too much. 

Go to Settings, Rollouts to configure how they run. Choose 1296 trials or a 
multiple of 1296:  2592, 3888, 5184, 6480, 7776. Chose World Class (which is 
2-ply) for the analysis level. 

I like to also select: 
Enable Stop on JSD; minimum trials = 1296; JSD from best choice = 3
This will stop rollouts on candidate play when they fall well behind the best 
play. 

I hope this helps.

Ian Shaw


-----Original Message-----
From: Bug-gnubg [mailto:bug-gnubg-bounces+ian.shaw=riverauto.co.uk@gnu.org] On 
Behalf Of Armin Fakeri
Sent: 10 January 2022 19:42
To: bug-gnubg@gnu.org
Subject: bug

hi im using ltest version og gnu backgammon 1.06.2 but after i choose 7ply cube 
decision analyze it hanging and i have a powerful cpu i have core i9 1190k plz 
fix this tnx