Mar 7, 2007

[New Version] v0.241b - Internal iterative deepening and changed back eval output

  • Internal iterative deepening was added along with hash move search before generating moves
  • The aspiration windows were reduced to 10 centipawns
  • The evaluation output was changed back to show the eval from the engine's point of view
Note: The internal iterative deepening does a mini-search (half the remaining depth) if there is no hash move for the current position. This mini-search finds a plausible move that will be tried first.

Once we have a hash move it will be searched before generating any other moves, that way if we get a cutoff from it (which should be quite likely) we saved some time.

I have chosen to not check the hash move for validity as of now. This can be risky since it is possible for two different positions to have the same zobrist key (possible but highly unlikely). I will probably add some sort of verifier in upcoming versions.



Anonymous said...

Just to say that I did the quick test for the version 0.24 and this version get more points than the version 0.23. The version 0.24 found 3 good answers (very quickly between 1 and 5 seconds) whereas the version 0.23 found only 2. (and before 0.23, 1 position was found). So there is a constant progress as you can also see following the ratings of your engine on the website "le fou numerique".

Jonatan Pettersson said...

Up until now I have had clear content to implement, like new evaluation, transposition tables, new move representation etc. All of which I knew would have a large impact on the overall strength of Mediocre.

Currently I am looking for the next 'breakthrough' to implement. To be honest I am not so sure where to look next.

SEE and other new move sorting techniques are probably the best bets.