CCRL Discussion Board

Previously, if the hash size was set to 256MB, it used only 134,217,728 of the availlable 262,144,000 bytes. I.e. 51.2% of the table size availlable. This was because I used a bit mask to truncate the zobrist key, rather than using a modulo division (which is really what I should have done from the ...

Hi all, Just wanted to announce Eubos v3.0. It's the first major release I've made for a couple of years. I've updated the search algorithm to a negamax implementation - found in a O'Reilly textbook on computer AI. I've given it a lot of testing at 12:0+8, circa 7000 games (takes an age at that cont...

Thanks very much. The provisional result is a little better than I was expecting, but I had seen Eubos v2.10 get better than a 60% win rate against BikJump (2102) over 550 games. This is the beauty of the CCRL testing you guys do. I can run many games against a single engine easily, but I never test...

Thanks, there's no rush and I'm very happy to wait my turn

Hi Gabor, If you can insert Eubos 2.10 (just released) into your test queue I would be very grateful. I have been working on pruning and reductions in the last few releases and, as a result, I believe Eubos is now in the 2000+ range. Making the step from pure brute force to selective path searching ...

I estimate Eubos is now at about 1890-1895 Elo, so that is an increase of about 50-60 points (on v2.4). I have greatly improved the speed of the move generation, but I still have a long way to go. I need to tune up the evaluation function some more and, beyond fixing the major bug, that shall be my ...

Hello again, I would have posted this over at TalkChess, but I seem to have an issue with my credentials over there. I have recently released a couple of versions of Eubos. I see v2.4 was picked up by one of the CCRL testers, thanks for that. Was it you Gabor? I just wanted to let you know that I ha...

Hi Gabor, thanks very much for the testing

Good to see the solid increase I had seen replicated in the CCRL listing. In a couple of weeks/months I might look at trying to introduce some pruning of the search tree, but for now I think I'll take a break!

Thanks again, Chris

Hi Gabor, I have recently released Eubos v2.2 on my github page. There are some change notes there about what is different, most importantly I no longer cap the extended search at each ply of the iterative deepening to an additional depth of 8 ply. this prevented Eubos seeing some imprtant tactical ...

Having spent the best part of several weeks testing different worker thread and hash table configurations (against a single opponent engine!) I can see the appeal of just testing with a single thread! The permutations start to get cumbersome very quickly. Even with one thread v2.0 should be stronger...

Hi Gabor, There is a defect in v2.0 which can cause one of the worker threads to get a null pointer exception and crash. It is possible that this could have affected the CPU load. However that would only happen when the hash table needed to be trimmed to make way for more transpositions, so dependin...

I skimmed over a few of the PGN games for Eubos and Pwned (it is great that they are made available). It does look like Eubos was just outplayed. I'll try and do some testing locally against this engine. Maybe I have a new nemesis to test against, it can be a new sparring partner. Thanks for the det...

Thanks for the testing. :D I see that Eubos only managed a 15% win rateagainst Pwned 1.3, that is comfortably the worst run I have ever seen. I will try and look through the PGN to find out what went wrong, on the surface it really looks like an outlier as that engine is (theoretically) weaker! Thou...

Great thanks, I will configure 1024 hash for my 4 core testing, from Arena, in that case.

Can I ask for a clarification of the CCRL rules surrounding multithreaded engines and hash size? I have added an option to Eubos called "NumberOfWorkerThreads", where the minimum setting is 1, the maximum is the number of cores available on the PC and the default is (num cores - 2). When t...

It is hard for me to be sure without seeing profiling data. However, it could be that the Java Virtual Machine is working particularly hard on garbage collection, for some reason. That can peak at between 8%-10% in my tests. It will depend on the size of the heap, as to how hard it is working. I'm c...

Thanks Gabor, I will check back with interest!

Hi CCRL, I released a new version of Eubos last week (v1.1.6). Over the last few months I have worked hard on optimisations to the move generation and reworked the move ordering. There was a defect where, if a move was a losing capture with check, it would be searched before a winning capture. This ...

I have created a couple of new versions of Eubos recently. The engine is now running in a hosted capacity on the Heroku cloud platform, connected to Lichess. To facilitate this I had to make a number of memory footprint optimisations. I no longer cache the MoveList in the hash table, which means tha...

I have added an official Eubos v1.0.8 release which has the dependencies repackaged in the JAR file as discussed. Otherwise it is functionally exactly the same as v1.0.7. After taking a holiday from Eubos programming, I'm probably more inclined to program an engine in C or C++, as I don't think I ca...

I mentioned above that another user had the same exception. I provided a build for him to try and he didn't get any further problems, it worked ok (with Java 8 at least). You can find the link to the build I gave him at the bottom of the thread on the bug: https://github.com/cjbolt/EubosChess/issues...

Yes, that's not good. Abstract Engine is a class from the JCPI package that should be included in the Eubos JAR file. I had another person run into this issue independent of you, they raised a bug about it on the GitHub page. But it doesn't seem to affect the majority of users. There must be somethi...

Disclaimer: I am in no way that clued up on Java, it isn't my day-job. However... it looks to me from that output like you might have not installed the Java Development Kit (JDK), just the Java Runtime Environment (JRE). That should be completely sufficient - the end user shouldn't need a JDK, that ...

Hi Gabor, It works for me with Java 14. Details follow: I uninstalled all my Java 8 JRE and JDKs. I then installed the following link https://adoptopenjdk.net/installation.html?variant=openjdk14&jvmVariant=hotspot#x64_win-jre The only step I did after extracting the zip file to C:\Program Files\...

Hi Gabor, I've not actually tested with Java 14. I would have thought that the JVM in Java 14 should support full compatability to Java 8, but I'm not sure. If you are thinking of doing some more testing with Eubos I can certainly try it out locally for you.