Chess engine Patch#
Chess engine code#
Chess engine license#

When you look at chess engine analysis, you see a lot of move variations and evaluations of the resulting positions. However, we should be aware of their limitations and what they can’t do to help you improve your chess. They can be very useful to check for blunders as well as practicing positions – such as endgames – when you don’t have a partner. Wilson Woodpusher: Oh yeah? Let’s have our chess engines play each other.Īm I saying that you should never use a chess engine to assist you with chess analysis or practice? No. Peter Patzer: 1500, but Slomodo 96.32a has a rating of 3700! Wilson Woodpusher: Ah…you are so wise, my friend. It says it’s +1.2 if you let it run to at least 33 ply! You need to use Slomodo 96.32a especially calibrated to analyzing such complex lines. Peter Patzer: Oh, my friend, don’t you know? Blockfish is terrible at assessing lines played by Nakamura. Wilson Woodpusher: What are you talking about? Blockfish 44.18 says that it’s only +0.32. Peter Patzer: Move 23 in the Najdorf Sicilian Sozin line you played is busted.

However, I think we must be very careful in using our silicon friend too much lest our conversations start to sound like this: Whether you are on an online chess server, internet forum, or even at the tournament hall, discussion of which chess engine one uses or what the latest version of Stockfish is seems to pop up frequently.

Chess engine Patch#

The only thing required is to fork the main Koivisto repository, make a branch for the tests and contact one of the core developers on our discord server or alternatively make an account and submit a patch yourself.Using chess engines for chess analysis and practice has become very commonplace. The OpenBench framework allows anyone with an account to test their changes. This community was a crucial aspect of Koivisto’s development as we exchanged many ideas with other engine authors. This group of engines is sometimes referred to as the OpenBunch and consists of other open source engines such as Ethereal, Berserk, Weiss, Halogen and many others. Koivisto is tested on the main OpenBench instance, along with other OpenBench engines. OpenBench then combines the results and then uses SPRT to calculate if a change makes the engine stronger by a statistically significant amount.

The testing is done using the OpenBench framework which allows distributing games across multiple machines. Our development process consists of brain storming about potential ideas that could work, trying multiple variations of these ideas and testing them to see if they make the engine stronger. Koivisto and the tools it relies on are developed on a daily basis by the core developers. In order to achieve this goal, we made all the tools used to develop Koivisto open source and they are available for other engine authors to benefit from. Koivisto has benefited from other open source engines and in turn, one of our main goals is to give back to the community.

Chess engine code#

We consider open source code to be crucial aspect of chess engine development.

Chess engine license#

In order to preserve the open source spirit, we chose to license the engine under the GPLv3. Most of the relevant parts of the code are commented in order to help people better understand what Koivisto is trying to achieve. Doing so, we used a variety of programming languages in addition to C++, ranging from CUDA to Python. A lot of external tools are required to develop a chess engines and in order to achieve compatibility, we opted to write most of these tools ourselves. The engine uses an external C library called Fathom for syzygy tablebase probing. Koivisto is programmed mainly in C++ and the core part of the engine consists of about 5000 lines of code.