Vapor Chess

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Vapor Chess is a 64-bit computer chess engine developed by Mike Leany. It is a clone, written from scratch, of his previous engine called Zilch. It runs under Linux, and Windows. It requires the use of a user interface that supports the UCI protocol, or an Xboard/Winboard interface in combination with Polyglot.

Vapor is currently in the early stages of development, but preliminary versions are available from the Download page.

For those who know what it means, it currently uses a plain vanilla alpha-beta search with check extension and iterative deepening. It now has a transposition table with a default size of 256 MB. It also uses piece-square tables for knights and pawns, but no other pieces yet.

The source code is available on github.

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Source Code Released

posted Nov 9, 2019, 10:13 AM by Mike Leany

I have released the source code for Vapor v0.02 on github.

Deja Vu

posted Aug 9, 2012, 6:40 AM by Mike Leany [ updated Aug 10, 2012, 6:23 AM ]

It's been nearly two years since I released Vapor v0.01, and finally I found some time to work on my chess engine. So now I am releasing Vapor v0.02, "deja vu", but only for linux for now.

I added the ability to detect draws by repetition and by the 50-move rule, which cut draws nearly in half (avoiding many draws which should have been wins) and gave an improvement of roughly 35 Elo. I also added a transposition table, which gives an additional 160 Elo improvement for the default size of 256 MB. This gives a total improvement of roughly 195 Elo over Vapor v0.01.

Unfortunately I can only release a Linux version at this time, due to code which my Windows cross-compiler doesn't like. Once I rewrite that portion, I will release a version for Windows (even though you should really all be running Linux anyway).

Also, note that the Linux binary was built and tested on Ubuntu 10.10. I make no guarantee that it will run in your Linux distrubution, whatever that may be.

Yep, I said Ubuntu 10.10; stupid Unity!

Page on Google+

posted May 29, 2012, 5:43 PM by Mike Leany

Vapor now has a page on Google+.

Bug Fix - Revision 12

posted Oct 22, 2010, 5:10 PM by Mike Leany

I have released Vapor 0.01 revision 12, which fixes a bug that would occasionally cause the chess engine to crash or hang. It is available from the downloads page.

Vaporware No More

posted Oct 10, 2010, 10:04 PM by Mike Leany [ updated Oct 10, 2010, 10:36 PM ]

Vapor Chess is no longer complete vaporware. Today, in honor of the date being 10-10-10 -- although that was mostly by happenstance -- I have finally released the first preliminary version: Vapor v0.01 -- aka 'condensation' -- for both Linux and Windows . And, by another lucky happenstance, the revision number for the Linux build just happens to be 10. I was hoping to keep the same revision number for the Windows build, but alas, mingw does not support the 'error' function, so I had to make some minor changes bumping it to revision 11.
This first version plays legal chess and will consistently beat mediocre players like myself. However, you will likely notice that it is completely unaware of draws by repetition, causing it to draw many games that it should win. I considered adding repetition detection for this first release, but decided it would wait until the next release when I expect to add transposition tables. It seems natural to implement them together, as they both require the ability to recognize when two positions are identical.

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