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        Arimaa >> Bot Development >> New sample bot based on bot_briareus
        
(Message started by: rbarreira on Jul 11^th, 2011, 6:09pm)

Title: New sample bot based on bot_briareus
Post by rbarreira on Jul 11^th, 2011, 6:09pm

I am releasing a sample bot based on bot_briareus, made in C and featuring:

Quote:

- minimax search with alpha-beta pruning
- fast parallel search (with splitting of work at the leftmost nodes in the tree, including the root)
- iterative deepening (iterating ply-by-ply, not step-by-step)
- transposition table, including step reordering (using zobrist hashing)
- killer move reordering
- extremely simple eval (material only, using the FAME method)

You can download it at:

http://109.74.204.218/threaded_sample_bot.tar.gz

The README.txt file has more information.

Title: Re: New sample bot based on bot_briareus
Post by Swynndla on Jul 11^th, 2011, 7:01pm

Thanks rbarreira - you are kind in helping the arimaa community even more! :D

This must be the first multi-threaded sample bot to be released.

Some questions if I may:
- the parallel search is or is not younger brother wait?
- I'm interested to know why you did ply-by-ply iterative deepening instead of step-by-step (don't most other bots do step-by-step? - I thought they did based on what I read in a previous post).

Thank you once again. :)

Title: Re: New sample bot based on bot_briareus
Post by rbarreira on Jul 11^th, 2011, 7:11pm

No problem!

The parallel search indeed uses the YBW idea.

By leftmost nodes I really mean the leftmost nodes only of the whole search tree. This includes the root, the first child of the root, its first child etc. So it's just a few nodes where splitting can happen, but this manages to keep most threads busy the vast majority of the time.

The iterative deepening was done ply-by-ply because of possible bugs when doing it step-by-step (as mentioned in at least one of the sample bots), and also because I was not convinced that step-by-step would be a plus. I decided to go with the safe choice, without yet testing step-by-step deepening.

Title: Re: New sample bot based on bot_briareus
Post by Swynndla on Jul 11^th, 2011, 8:20pm

Nice! I don't know what to think of step-by-step iterative deepening myself (ply-by-ply seems so much more intuitive). If you even test step-by-step I'd be interested in hearing what you find out.

Title: Re: New sample bot based on bot_briareus
Post by hyperpape on Feb 29^th, 2012, 4:24pm

This might be good to post to the downloads section: http://arimaa.com/arimaa/download/.

Title: Re: New sample bot based on bot_briareus
Post by rbarreira on Feb 29^th, 2012, 4:52pm

Before that I should put up a new version with some bug fixes though...

Title: Re: New sample bot based on bot_briareus
Post by thomastanck on Mar 27^th, 2012, 10:21pm

How's the fixing going? Good luck rbarreira! :)