Frittle

frittle

(fritt'-ul) n. a temporary mark on the skin caused by the impression of a textured surface. [... inspired by the similar pattern on the butterfly known as Frittilary, for its checkered markings, from Latin fritillus meaning a chess board].

Frittle is an amateur computer chess engine. It is completely free and open source. Currently, Frittle is compatible with WinBoard/XBoard chess protocol. Frittle has been developed by Rohan Padhye, a student of computer engineering from Mumbai, India.

Current Status

Frittle is currently in still in heavy development. It is very basic although it has been known to win against amateur human players and engines. There is still scope for a lot of improvement. Frittle is estimated to be of around 1200-1300 Elo strength. This is a provisional rating as there has been very little testing done on a real scale.

Download

You can download the latest release of Frittle through the SourceForge.net Downloads page. There are 3 types of releases with each version:

• A standalone JAR package (default release) that can be executed on any JRE. Opening book included.
• A 32-bit Windows executable (.exe). Windows users download this release if you want to run Frittle with a GUI. Opening book included.
• A source package is also available in case you want to read the source code (in Java) or modify it under the terms of the GNU General Public License.

Usage

To run Frittle, you need to have a working Java Runtime Environment. If not, Get Java. Minimum Java 1.5 is required. Frittle does not come with a Graphical User Interface. You can play it using the command line or through any GUI that supports the XBoard protocol. Examples of such GUIs are WinBoard (Windows), XBoard (Linux) and Arena (Windows). For instructions on using Frittle with these GUIs see below.

Running Frittle on the command line

Simply open up your console/terminal to the directory in which you extracted Frittle and then type the following:

java -jar Frittle.jar

Type help to list the available commands you can use. To just start playing, enter your move (eg. e2e4).

Frittle with Graphical Interface on Windows using WinBoard

First, download and install WinBoard. This is a graphical interface that lets you play chess against a number of compatible engines such as Frittle, Crafty, GNUChess, etc. Once you install WinBoard, download Frittle and extract the files in the same directory in which you installed WinBoard. Now, create a new shortcut on the desktop and in the 'path' field enter the following:

"C:\Winboard\winboard.exe" -cp -fcp "Frittle" -scp "Frittle"

Change the path in blue if you installed WinBoard in some other directory.

Voila! Now when you double-click on that shortcut it should open up the GUI with Frittle loaded. You might ask why you have to mention Frittle twice - That's to tell WinBoard that in Computer vs. Computer mode you want both the First Computer Program (-fcp) and the Second Computer Program (-scp) to be Frittle. If you want some other engine to play against Frittle, you can (assuming the other engine has been installed). For example, to play against GNUChess (included with some Winboard releases):

"C:\Winboard\winboard.exe" -cp -fcp "Frittle" -scp "GNUChess"

Of course, if you installed WinBoard in some other drive or path, then change the path of WinBoard accordingly. If you installed Frittle somewhere else (that is, not in the WinBoard directory), you can still link to it but then you must also specify the path where Frittle is stored. For example,

"C:\Winboard\winboard.exe" -cp -fcp "Frittle" -fd "C:\Frittle" -scp "Frittle" -sd "C:\Frittle"

In this case, change the blue path to wherever you might have installed WinBoard, and change the red path to wherever you extracted the files in the Frittle package. -fd indicates the First program Directory and -sd indicates the Second program Directory (this might be different if you are playing against a different engine).

Frittle with Graphical Interface on Linux using XBoard

This is somewhat similar to the method mentioned above. Download and install XBoard. Then download Frittle and extract the files to the directory in which you installed XBoard. Then simply perform the following command:

You can also create a KDE/Gnome launcher for the above command to allow quick launching from the desktop.

Technical Details

Frittle is written in the Java programming language. The current version uses the following components/techniques:

• XBoard Chess Engine Communication Protocol
• Command Line interactivity:
  • Moves in co-ordinate notation (eg. e2e4)
  • FEN support
  • For a list of commands type help after launching Frittle
• Alpha-Beta Pruning with Principal Variation Search
• Transposition Tables
• Iterative Deepening
• Quiescence Search
• Killer moves heuristic
• Opening Book
• Evaluation based on material, positional value and pawn structure
• Quickest Mate attack, or Resign on forced loss
• Time Control (Tournament mode and Fischer style)
• Pondering (Thinking on opponent's time) [UNSTABLE]

Still to come

• Draw handling (to get a draw when in a losing position, or avoid drawing when winning)
• Null Move pruning
• Late Move Reductions
• Endgame Tablebases
• A better evaluation function (based on king safety, etc.)
• Machine Learning
• Polyglot Opening Book support
• UCI compatibility
• SAN/PGN support

Contact Details

You can contact the author Rohan Padhye for any queries or just to say hi.
E-mail: verminox@gmail.com. No I am not afraid of spam.

Acknowledgements

The Beowulf project (author: Dr. Colin Frayn) for its articles and opening book. Although the opening book provided for download is generally used for machine learning, Frittle uses it directly, assuming the playing frequencies as move weights. Until Frittle implements its own opening book strategy, this is the way it will go.

This project is hosted by: