World Draughts Forum

BertTuyt wrote: Sun Sep 21, 2025 14:55 The perft result from Ed was (most likely) without bulk-counting, which should not be neglected.

I looked at some old commits in SVN. Bulk counting was added on July 17, 2008.

My newest PC is a laptop with an I7-12700H CPU. Base clock is 2.4 GHz, but it gets up to about 4.5 GHz with turbo boost.

perft(1) 9 nodes, 0.00 sec, 9 knodes/sec
perft(2) 81 nodes, 0.00 sec, 81 knodes/sec
perft(3) 658 nodes, 0.00 sec, 658 knodes/sec
perft(4) 4265 nodes, 0.00 sec, 4265 knodes/sec ...

If you only want to know if it is a definitive win for black, without determining the path to win, you can do a 100 ply minimal window search in move 12 for white. Depending on your score for definite win, one can use a window such as -1000 .. -999. If it fails low, you are sure that black wins ...

I let kingsrow play it out in autoplay at 2min/move, 16 search threads, and it ended in a black win. Of course that's not definitive. A better way to analyze it is using dropout expansion, to automatically explore all reasonable lines of play and build a db. It would probably take days or even weeks ...

At first glance I thought the black/white positions might be symmetrical mirrors, but they aren't quite, the man on 43 would have to be moved to 44.

Kingsrow thinks that white's first really weak move was 11. 39-33. The search score jumps from 12 to 56 almost instantly. 50-45 instead maintains a ...

Flits (white) played 38-33 and the game was concluded soon as a win for Kingsrow.
A better defense seems to be 40-35 (9-14) 32-28 (21-27) 37-32 (27-31 or 14-20) with a possible draw.
I'm not sure this sequence is right and that this ends in a draw, Ed might have the final verdict here.

Kingsrow ...

Ed this is about dxp not hub.

It's about automating engine matches using the PyDraughts library. The PyDraughts library supports both dxp and hub. I'm assuming that each engine will talk to the PyDraughts script so that it can control the games. It shouldn't matter which protocol PyDraughts uses ...

Hi Gijsbert. Kingsrow supports dxp but it can only be started interactively with gui commands. However there is a Hub version of kingsrow that provides what you need. Hub give you control of all the kingsrow settings, and more options for time control. It does support the x moves in y minutes that ...

Thank you for your answer. I have a question, is it possible to save movements, for example 02, 07, 09? Do I have to fill in the zeros in the game record myself.

No, there is no requirement in the PDN standard for the square numbers in moves to have leading zeros, so kingsrow does not generate ...

Copy the text of the moves to the clipboard with CTRL-C, paste it into kingsrow with CTRL-V, and now copy it from kingsrow to the clipboard with CTRL-C. I just did it, here is a paste from the clipboard:

[Event ""]
[Date "2024.09.04"]
[White ""]
[Black ""]
[Result "*"]
1. 34-30 20-25 2. 32-28 25x34 ...

Bob Hyatt did some testing on the effects of hash collisions in his chess engine Crafty. His results are published in this short paper: http://craftychess.com/hyatt/collisions.html . His conclusion is that even a gross error rate of 1 in 10,000 positions does not change game outcomes or weaken play ...

I wanted the ending bases to be equal to both programs.
Yes, that is clear, but the question is, what are you trying to measure with these engine matches? If it is to measure the relative strength of engine A vs engine B in normal match conditions, it's not doing that, because kingsrow uses an 8pc ...

My 16-core PC is not available at the moment, but I looked at it with a single thread. It takes about 7 seconds for kingsrow to switch from 20-15 to 28-22, so it's not that surprising that kingsrow could not see that with 16 threads given the short time controls that give an average 0.5 sec/move. I ...

The win (and only win in this match) of Ares in game 123 is a little strange.
The move from KR 43. 20-15 was definitely wrong and losing, whereas 43. 28-22 27x18 44. 42-37 41x43 45. 49x38 is a draw.

I expect that with 16-cores KR would not have search problems.
Ed, can you give some light, is this ...

It is a pity that the bug still exists in both Flits versions.
Another thing, although Flits is relatively old, and basically not changed since many years, it has really potential for improvements.
If one (with the proper knowledge) would include search extensions like better pruning and LMR, I'm ...