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by hgm
Sun Apr 11, 2021 9:26 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: The mailbox trials
Replies: 110
Views: 8206

Re: The mailbox trials

The puzzling thing is that (on my laptop, this time) using the same, complete list of moves for the leapers on every square, rather than a per-square adapted list that only contains moves that stay on board. I saw the same thing on my PC with one of the earlier versions, when I first implemented the...
by hgm
Sun Apr 11, 2021 2:31 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: The mailbox trials
Replies: 110
Views: 8206

Re: The mailbox trials

Magic Move Step Leapers in Chess can only have King steps or Knight leaps, and of each there are only eight. So in principle 4 bits would be enough to encode what move is meant. But using a lookup table for decoding these would defeat the purpose of eliminating load instructions. I was hoping that ...
by hgm
Sun Apr 11, 2021 9:31 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: The mailbox trials
Replies: 110
Views: 8206

Re: The mailbox trials

Well, the fact that my PC went dead yesterday (graphics card?) will not be very beneficial for the progress of this project. But let me dwell on some theoretical aspects. We see that a significant fraction of the time (20%, in some compiles this even went up to 24%, without any clear reason) is spen...
by hgm
Sat Apr 10, 2021 3:27 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: The mailbox trials
Replies: 110
Views: 8206

Re: The mailbox trials

I made the map update for non-captures now also incremental. For that I had to add a new routine for collecting the attacks on a hitherto unoccupied square, and then blocking all slider attacks that it catches. (I.e. remove those from the attackers sets of the downstream pieces they were originally ...
by hgm
Sat Apr 10, 2021 1:01 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: The mailbox trials
Replies: 110
Views: 8206

Re: The mailbox trials

I moved the stuff to Linux, so I could do profiling to see where the time goes. (Un Cygwin profiling never worked for me: it always lists all functions as using 0% of the time!) This gave the following list: Each sample counts as 0.01 seconds. % cumulative self self total time seconds seconds calls ...
by hgm
Sat Apr 10, 2021 8:47 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: The mailbox trials
Replies: 110
Views: 8206

Re: The mailbox trials

Although I haven't been able to exploit this yet to achieve further speedup, I want to dwell on this some more. Because I have the feeling I am really on to something. Moving the code for finding the MVV to the parent node / makemove was originally inspired by the wish to avoid the expensive attack-...
by hgm
Fri Apr 09, 2021 3:48 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Fairy-Max and chess variants rules generalization question to HGM
Replies: 8
Views: 218

Re: Fairy-Max and chess variants rules generalization question to HGM

Well, there is a wisdom known as the "maximum flexibility, minimum usefulness principle". MaxQi was a sort of half-hearted attempt to make the (source-code-wise) smallest Xiangqi engine, just as micro-Max was an attempt to make the engine with the best Elo/sorce-size ratio. And since I already had F...
by hgm
Fri Apr 09, 2021 1:18 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Fairy-Max and chess variants rules generalization question to HGM
Replies: 8
Views: 218

Re: Fairy-Max and chess variants rules generalization question to HGM

Janggi and Xiangqi are fairly unique amongst chess variants, by having location-dependent movement capability of its pieces. Zone confinement can be considered as a special case of this (where the pieces lose the moves that would leave the zone when they are next to a zone boundary). But in Xiangqi ...
by hgm
Fri Apr 09, 2021 12:10 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: The mailbox trials
Replies: 110
Views: 8206

Re: The mailbox trials

I am still a bit in doubt here, on what to do when the pre-existing threat is no longer valid. We would have to keep searching for a victim amongst the remaining members of the 'worseThreats' victim set. One that is attacked after the move. Which is a different test than for finding a pre-existing t...
by hgm
Fri Apr 09, 2021 9:49 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: The mailbox trials
Replies: 110
Views: 8206

Re: The mailbox trials

Finding the MVV The attack map makes it easy to see whether a piece is attacked, by just consulting its attackers[] element. But the capture generation still has to loop through the piece list top-down for finding pieces that are attacked. Some time could be saved by somehow skipping the test on pi...