Aart's Blog

I am extending Chess for Android with a feature to run automatic engine-engine matches between UCI engines that have been "natively" compiled for Android. After importing two UCI engines, or using the built-in Java engine for one, a fixed number of games is played using random openings from the built-in book while allocating a fixed time per move. All games are saved in a "match.pgn" file, which can be used by another chess program, such as Arena or Chessbase. A Chessbase-generated cross-table for a 1-second-per-move tournament between some UCI engines compiled for Android is shown below. I hope to release this feature sometimes early in January.                  1          2          3          4          5 1 Stockfish 1.9  ********** 11½0100101 111111½111 1111111111 1111111111 35.0/40 2 Crab 1.0 beta  00½1011010 ********** 111½1½1111 1111111111 1111111111 33.5/40 3 GNU Chess 5.07 000000½000 000½0½0000 ********** ½½11111110 1111111111 19.5/40 4 BikJump v2.1

The vacation just started, and Karina and her friend Ella are enjoying 50 lap races on our Carrera racetrack. Nice to see the difference between a year ago, when the girls crashed the cars most of the time, and now, when they actually understand braking before and accelerating in a curve. Still, lots of repairs to be done on the cars when this race is over. I like the Carrera Digital 132 race track. Cars have regular and braking lights, can switch lanes on designated lane change sections, and the speed, braking power, and fuel tank capacity can be set individually for each car. When cars run out of gas, lights are blinking as they slow down, and a visit to the pit stop is required first. Moreover, up to six cars can race together, or autonomous cars can be programmed to make racing harder while an electronic lap counter keeps track of interesting statistics.

A merry Christmas and a happy 2011 for all my blog readers. In the picture, you see the snow covered city hall of my home town Gouda in the Netherlands. In "sunny" California we just get rain :-)

Continuing the detour in checkers. I also released v1.2 of BikMove , a checkers engine plugin to Martin Fierz' CheckerBoard application. New features include: Added internal iterative deepening to search Configurable transposition table and endgame database cache Improved evaluation function Avoid querying Fierz's database when *either* side can capture Below are results of a 3-move openings match between BikMove v1.2 and other engines (1 second-per-move, 256MB hash, 256MB database cache, 2-8 piece endgames, best-move for engines that have their own book). BikMove v1.2 vs. Easy Checkers 1.0   : W-L-D: 284-  0-  4  99% BikMove v1.2 vs. Simple Checkers 1.14: W-L-D: 136- 21-131  70% BikMove v1.2 vs. GUI checkers 1.05+  : W-L-D:   9-108-171  33% BikMove v1.2 vs. Cake1.8 + huge book : W-L-D:   0-152-136  24% BikMove v1.2 vs. Kingsrow 1.16d      : W-L-D:   1-181-106  19% For comparison, also some results under similar conditions with v1.1. BikMove v1.1 vs. Simple Check

To improve endgame play, I have added a few "distance-to-win" endgame databases to Checkers for Android (K-K, p-K, p-p, KK-K). These databases are small enough to reside in memory and are queried during the engine search. In the screenshot below, for instance, the engine (playing black) announces that it will win in 20 moves. If you are up to the challenge, just download version 2.4 of Checkers for Android from the market.  

A movie of a robot having some fun fetching and throwing a ball.

Through Google, I signed up as volunteer for a Lego engineering mentoring/outreach program in a local school. This was a very good excuse for Karina and me to get reacquainted with our Lego Mindstorms NXT kit (also see our earlier Mindstorms adventures ). As you can see, we had lots of fun together.

It is long overdue, but I finally wrote brief manuals for Chess, Checkers, and Reversi for Android that explain the full menu structure of the games. I plan to add more explanation here over time. Please let me know if you have suggestions.

It is minor, but the latest release 2.4.3 of Chess for Android now shows a red circle around the king as an in-check (or mate) warning when the move coach is enabled. A sample screenshot is shown below. This version also improves UCI engine unloading on exit.

The adventure that started in Indiana in 1996 and continued in California in 1998 reached a very special point today. I received my U.S. Citizenship. Thanks, America, for being my home for so many years and welcoming me into the American family.

I just released version 2.4.1 of Chess for Android with the following changes: Ability to install application on SD card Moved navigation buttons down Few improvements to UCI engine support To verify that UCI engine support works for third party engines as well (not just for BikJump), I downloaded sources of ZCT0.3.2500 (by Zach Wegner) and Crab1.0Beta (by Tord Romstad, Marco Costalba, Joona Kiiski, Adam Kleng) and compiled these "natively" for Android. Importing and playing the engines work fine. As before, instructions on setting up an UCI engine are given at UCI for Android .

Because it is hard to print all information from the UCI engine on the phone screen, I am toying with a feature where the current move considered by the UCI engine is shown graphically. Below is a short demo of this feature. Let me know what you think!

I just released version 2.4 of Chess for Android at the Android Market with the following new feature: basic UCI engine support (ability to replace built-in Java engine with any third party UCI engine compiled "natively" for Android) Instructions on how to setup an UCI engine are given at UCI for Android . As far as I know currently only BikJump is available as stand-alone UCI engine for Android. Although stronger than the built-in engine, I hope I will be able to add links to much stronger third party UCI engines soon. Please note that support is still rather basic (elaborate setup, only tested on one engine, GUI does not support engine options, time control restricted to time-per-move, position sent as FEN, making the engine more prone to three-fold repetition, no tournaments, etc.). Nevertheless, I hope it is an interesting start.

Here is an UCI engine running on a Nexus One in Chess for Android, probing the complete 3- and 4-piece Nalimov endgame tablebases (29.6 MB) from SD card. Here is a screenshot where the UCI engine already reports a mate (using the tablebases), while the internal Java engine only reports a negative score for white given a search tree of depth 9. Steps to make this work are shown at UCI for Android .

The UCI engine output is now presented in a slightly better format, where information is broken up into individual fields. Also, I have compiled BikJump v2.1 natively for Android, which is more elaborate multi-threaded bitboard-based engine that also supports the Nalimov endgame tablebases (with kind permission from Eugene Nalimov and Andrew Kadatch). I copied a few tablebases into the emulator's SD card and started the engine analysis. As can be seen in the screenshot below, the engine together with the probing code run fine on the Android emulator.