Author Archives: admin

PVS – Another Fast Fail

Posted on September 23, 2020 by admin

After the failure with aspiration windows I decided to implement PVS . The idea here is that, with proper move ordering the first move is usually the best. That being the case, it makes sense to search all of the … Continue reading →

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Aspiration Windows – a Fast Fail

Posted on September 18, 2020 by admin

Earlier this week I implemented aspiration windows to chess4j. It’s a very simple concept. In the iterative deepening loop, the depth 1 iteration is processed as usual, with an alpha bound of “negative infinity” and a beta bound of “infinity.” … Continue reading →

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Stopping at half time – and on making small changes

Posted on September 13, 2020 by admin

Great things are done by a series of small things brought together. — Vincent Van Gogh. The last few changes — adding null move pruning, hashing, and a quiescence search — have had major impacts on playing strength, which was … Continue reading →

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Null move pruning

Posted on August 1, 2020 by admin

The null move heuristic has been added and yielded another pretty solid increase in Elo. For the uninitiated, a “null move” isn’t a real over-the-board move of course, it’s just a heuristic that can be used to terminate a line … Continue reading →

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Hashing

Posted on July 22, 2020 by admin

Both chess4j and Prophet now have hashing. Maybe I should say that chess4j has hashing again, because it did have hashing before as I wrote about here. As stated in a previous post, I basically “tore down” the search in … Continue reading →

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Quiescence Search

Posted on July 5, 2020 by admin

It’s not very often that you can make a change that will net your program 350 Elo, but that’s exactly what I just did! A quiescence search was added to chess4j and Prophet4, resulting in a dramatic increase in playing … Continue reading →

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Pondering and Analysis

Posted on July 1, 2020 by admin

chess4j can now ponder! If you’re not familiar with that term, it means that the program will make use of the time the opponent is on move. It does this by predicting the move the opponent will make, and thinking … Continue reading →

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chess4j + Prophet4 rewrite status 6/14/20

Posted on June 14, 2020 by admin

Support for time controls has been added to both Prophet and chess4j. Each is capable of playing with a fixed time per move or incremental chess clocks. They can use conventional chess clocks as well, but the timing strategy doesn’t … Continue reading →

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Prophet4 rewrite status 5/31/20

Posted on May 31, 2020 by admin

The last couple of weeks have been focused on transitioning P4 from a single threaded engine that plays to a fixed search depth to a multi-threaded engine that can respond to commands while searching, and can search for a fixed … Continue reading →

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chess4j + Prophet integration status 5/17/20

Posted on May 18, 2020 by admin

Several months ago I wrote about a proof-of-concept JNI integration between chess4j and Prophet4. At the time I had managed to compile Prophet4 as a static library, load that library into chess4j and write a JNI layer. The only function … Continue reading →

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