Mussaurus 0.1-prealpha - a poor man's Vice

[tmokonen]

One thing I noticed when looking at your code is that the move ordering doesn't take pawn promotions into consideration. The game you posted is perfectly reasonable given what you have in your program so far, but your program did get caught by not noticing the dangerous passed pawn until it was too late. Adding promotions to your move ordering would help in situations like this, especially if passed pawn knowledge is added to the evaluation as well. I didn't notice any outright bugs in the search.

[shinkarom]

Thank you for checking the code. I noticed one - the null move pruning doesn't take zugzwang into account, but until I find a satisfying condition for zugzwang it will be buggy.

[Terje]

Thank you for checking the code. I noticed one - the null move pruning doesn't take zugzwang into account, but until I find a satisfying condition for zugzwang it will be buggy.

If you followed VICE exactly you'll have the condition that the side to move has to have a "big piece" aka non-pawn, non-king to perform a null move, however VICE mistakenly counts the king as a big piece meaning it will always allow null moves. Fixing this, not counting the king, in my engine (also based on VICE) allowed it to solve a lot of zugzwang positions it previously could not.

[shinkarom]

That needs to have, like Vice, incrementally updated piece counter, which is work in progress.

[Richard Allbert]

Thank you for checking the code. I noticed one - the null move pruning doesn't take zugzwang into account, but until I find a satisfying condition for zugzwang it will be buggy.

If you followed VICE exactly you'll have the condition that the side to move has to have a "big piece" aka non-pawn, non-king to perform a null move, however VICE mistakenly counts the king as a big piece meaning it will always allow null moves. Fixing this, not counting the king, in my engine (also based on VICE) allowed it to solve a lot of zugzwang positions it previously could not.

Yep, this was a stupid mistake, thanks for pointing it out.

[Guenther]

Thank you for checking the code. I noticed one - the null move pruning doesn't take zugzwang into account, but until I find a satisfying condition for zugzwang it will be buggy.

If you followed VICE exactly you'll have the condition that the side to move has to have a "big piece" aka non-pawn, non-king to perform a null move, however VICE mistakenly counts the king as a big piece meaning it will always allow null moves. Fixing this, not counting the king, in my engine (also based on VICE) allowed it to solve a lot of zugzwang positions it previously could not.

Yep, this was a stupid mistake, thanks for pointing it out.

Richard, did you just reveal yourself as the (unknown) author of Vice, or am I just confused? :)

[shinkarom]

I only know that Bluefever's Arena identifies him as RICHARD2.

[Guenther]

I only know that Bluefever's Arena identifies him as RICHARD2.

viewtopic.php?f=2&t=54084&p=593625#p593625

Ouch, with that link above it means it never was a hard riddle.
At least I was in hiatus when the above quote happened and no one noticed ;-)

Here is the wayback link to Richards Lime and Jabba (chess engines) - we had lot of fun in those times,
when I was still broadcasting.

https://web.archive.org/web/20160125173 ... /index.php

[shinkarom]

I'm deleting Mussaurus.
With my current chess skill it seems dishonest to create a chess engine; moreover, it seems not right to make such a long term project for which I don't have the stamina, and which will be drowned in bugs.

[Ovyron]

So you didn't enjoy working on the project?