Jan 24, 2007

[Other] Better but some bugs

I ran a few games between Mediocre with transposition tables and Mediocre v0.12b, the new Mediocre won pretty much every game except the ones it forfeited due crashing or playing illegal moves. :)

It searches about a ply or two deeper in every given middle game position, and much deeper in end games.

There are still some big bugs to be sorted out, but they are atleast getting fewer.

The repetition draw detection in search tree is a hassle and I will wait with it a bit, atleast until after I have written the new evaluation. However the draw detection with positions from the game history works without problem, with new zobrist keys instead of the slow FEN-approach I had before.


Bajusz said...

This is just let you know your blog is rather intresting to read! I'm involved with pychess (at googlecode) and your posts are wery useful for me. I wish when you finish your program (yes, i know developing a chess program is a never ending story), you can join to pychess development and share your valuable experiences.

Fritz said...

It is good to see how your engine gets stronger; I expect you could gain a lot of strength by changing the king safety function: The distance to the king is not a good measure of the danger of a piece: If a bishop, rook or queen threatens a neighbour of the king, the distance of the piece is immaterial; also, pieces aren't necessarily able to engage in an attack just because they are near to the king.

I would prefer to grade pieces attacking immediate neighbours of the king as threats - this is more expensive to calculate, but I currently don't expect your evaluation to be the speed bottleneck.

Jonatan Pettersson said...

Yeah fritz, your idea seems to be alot better than the one I have currently. And about the evaluation not becoming a bottleneck in the near future is probably true as well.

The current evaluation is just a very rough draft, and I intend to rewrite it completely as soon as I am done with the transposition table.

And bajusz I took a look at the pychess thing, it looks interesting. We'll see what the future holds. :)