Alberto Alonso Ruibal's Blog

Chess engine development is one of the most brain-crushing activities I’ve been involved on the last years. Last nigths I was working again on my Carballo Chess Engine with some advances.

First of all I decided to leave Negamax and go with Principal Variation Search (PVS). Also decided to implement separate methods for root nodes, PV nodes and null window searches. On previous experiments PVS was performing worse than Negamax, but I discovered the reason: the aspiration window has some implementation issues with PVS: when the search for a move fails low at the root node the move must be researched enlarging the window.

I was very stranged of why Futiliy Pruning was not working for me, but finally discovered the reason: a simple sign change after evaluation was the reason! Also implemented to store the evaluation values on the Transposition Table (TT).

The next step: why Carballo searched much less depths than other engines, it was due to quiescence search. I was generating checks for the first 4 PLY’s of quiescence, but some other engines not, so this was the reason. I decide to generate only checks on the first PLY of quiescence and only for PV nodes. Also modified a bit the move generation to optimize for quiescence.

During this time also found many interesting bugs, I was storing on the TT the bound and not the score when failing high/low, also on PV nodes is better to use only the TT for ordering and not to return scores from it, this helps avoiding draws. Also found a serious bugs involving time management (was taking as reference opponent’s time) and with contempt factor on IID searches corrupting TT entries. Finally added a Pawn Push Extension and removed the Recapture Extension and now some extensions now depend of the node type.

Running some test tournaments, I hope to get some good results soon and add the improved engine to my Mobialia Chess.

Jim Ablett has published a packaged executable for my Carballo chess engine. He also made a pretty logo for it, shown here. Check his page to download executables for Carballo and a lot of other chess engines: Jim Ablett’s Winboard Chess Page. Thanks Jim for your great work!

Mañá vou facer unha presentación de Android e organizar un pequeno workshop na SobrosoParty (http://www.sobrosoparty.es). Tamén falarei do meu novo proxecto Mobialia e das aplicacións para Android que teño feitas. A presentación de mañá se pode descargar no seguinte enlace:

• android_sobrosoparty.pdf

The new version 2.0 adds the support to play online on freechess.org (FICS). You can play against people all around the world and compare your chess knowledge. Thousands of hours of entertainment with this new version.

Also has many improvements on the interface and gameplay, which makes Mobialia Chess 2.0 the best chess app for Android.

Try it! The LITE version is free, and the complete version is avaiable for only 1.99 EUR at the Android Market.

Check all the Mobialia Chess for Android features at http://www.mobialia.com/chess

Lukas Laag has written me about his new  GUI for the Carballo Chess Engine  using the Google Web Toolkit (GWT) and his SVG Graphics Library for GWT, libgwtsvg.

GWT is provided from Google to develop applications in Javascript programming in Java. It conterts the Java code to Javascript, and the application is run on the browser, without any additional plugin.

This interface is quite better than the sample Applet from Carballo, it has move history, legal move hightlighting, and SVN graphics. It can be used from:

http://www.vectomatic.org/gwt/libgwtsvg-chess/libgwtsvg-chess.html

He also wrote an article explaining the difficulties of his project. Thanks Lukas for your work.

Recently, navigating the Debian repositories I found Rakarrack, an Open Source Linux program to simulate various guitar effects in real time. This sound effects are often done with expensive physical sound processors, but this application makes it all with only one cheap computer (well, I suppose that the quality will rely a lot on the sound card).

Each effect is a module and and has its owns parameters which can be adjusted with sliders from the GUI. Multiple effects can be chained in different configurations.

For the audio input and output, It uses the Jack Sound Server. Initially Jacks is a bit complicated to set up but is very versatile. I use the qjackctl to configure and run Jacks simplifying this task. First we start qjackctl and from its GUI, start the jack server. Then run Rakarrack, and with qjackctl we connect Rakarrak to the system sound output and input:

The latency (the sound delay) of Rakarrak is quite good, but depends a lof of the Jack server configuration. This snapshot is the configuration that I am using from qjackctl: the Latency is the important value, and can be minimized adjusting the “frames by period” parameter:

I played a lot using different presets (it has lots of pre-configured) and there are some quite good, but others does not sound as good as a physical pedal, maybe also by le low quality of my notebook sound card.

It also has an integrated guitar tuner, but for this purpose I prefer Lingot from my Friend Iban Cereijo.

A lot of years ago I tested Guitar Rig, a quite pretty (and expensive!) windows applicattion for the same purpose, but then the latency of the sound was too high. Rakkarrak is simpler but enough for most non-professional guitar players, and I like it a lot!

http://rakarrack.sourceforge.net/

Ante a inclusión no anteproxecto de lei sobre a economía sostible das modificacións lexislativas que afectan o libre exercicio das liberdades de expresión, de información e o dereito de acceso á cultura a través de Internet, os xornalistas, blogueiros, usuarios, profesionais e creadores de Internet manifestamos a nosa firme oposición ao proxecto, e declaramos que …

1. Os dereitos de autor non poden estar por riba dos dereitos fundamentais dos cidadáns, incluíndo o dereito á privacidade, a seguridade, a presunción de inocencia, a tutela xurisdicional efectiva e a liberdade de expresión.
2. A suspensión dos dereitos fundamentais é e debe seguir sendo unha competencia exclusiva do Poder Xudicial. Nin un peche sen unha sentenza. Este anteproxecto, ao contrario do disposto no artigo 20.5 da Constitución, pon en mans dun corpo non xudicial, un organismo dependente do Ministerio de Cultura, a potestade de poder impedir o acceso dos cidadáns españois a calquera páxina web.
3. A nova normativa vai xerar inseguridade xurídica en todo o sector tecnolóxico español, perxudicando unha das poucas áreas de desenvolvemento e futuro da nosa economía, dificultando a creación de empresas, introducindo barreiras á libre competencia, e trabando a súa expansión internacional.
4. A nova lexislación proposta ameaza aos novos creadores e dificulta a creación cultural. Coa Internet e os sucesivos avances tecnolóxicos democratízase drasticamente a creación e emisión de todo tipo de contidos que xa non veñen principalmente das tradicionais industrias culturais, se non de moitas fontes distintas.
5. Os autores, como todos os traballadores teñen dereito a vivir do seu traballo con novas ideas creativas, modelos de negocio e actividades relacionadas coas súas creacións. Tentar de soster con modificacións lexislativas unha industria anticuada que non sabe adaptarse a ese novo ambiente non é xusto nin realista. Se o seu modelo de negocio baséase no control das copias dos traballos e na Internet non é posible sen violar os dereitos fundamentais, terán que atopar un outro modelo.
6. Cremos que as industrias culturais precisan para sobrevivir de alternativas modernas, eficaces, credíveles, accesíbeles e que atendan os novos usos sociais, en vez de limitacións tan desproporcionadas coma ineficaces para o fin que afirman perseguir.
7. Internet debe funcionar libremente e sen interferencias políticas patrocinadas por grupos que buscan perpetuar modelos de negocio obsoletos e impedir que o coñecemento humano siga sendo libre.
8. Demandamos que o Goberno asegure por lei a neutralidade da rede en España, ante calquera presión que poida ocorrer, como un marco para o desenvolvemento dunha economía realista e sostible para o futuro.
9. Propoñemos unha reforma real dos dereitos de propiedade intelectual co fin de: retornar á sociedade o coñecemento, impulsar o dominio público e limitar os abusos das entidades xestoras.
10. Nunha democracia as leis e as súas modificacións deben ser aprobadas despóis do debido debate público e de ter consultadas todas as partes implicadas. É inaceptable que se fagan modificacións lexislativas que afectan os dereitos fundamentais nunha lei non orgánica e que trata de outro tema.

Na úlima Noite Galega das Telecomunicacións (a cena anual do colexio de enxeñeiros de telecomunicación) tiven a sorte de coñecer a Xosé María Fernández Pazos, director da Revista Codigo Cero e do programa da Radio Galega Banda Ancha. Por certo, a última hora, a directiva do colexio tomou a esperpéntica decisión de non reparti-los exemplares do número especial da revista “Código Cero” editados para a Noite Galega, supoño que é unha cacicada de Televés, que ten copada a xunta directiva, xa que na portada da revista aparecía propaganda de BluSens e de Arteixo Telecom.

Son de agradecer estas iniciativas nuha terra na que a radio e a televisión públicas están inundadas de vacas e mariscadores, un auténtico oasis no deserto. Todo o meu apoio para eles:

Blog do Programa Banda Ancha

At last, the first “stable” release of my chess engine. The main new features are:

• Static Exchange Evaluator (SEE): the biggest change,  affects move ordering introducing more move generation phases, also affects LMR, etc.
• New “experimental” evaluation function, with King Safety, X-Ray attacks and improved mobility
• Recapture extension, also changed a lot the extension mechanics adding fractional extensions
• Quiescense search now only generate checks the first 4 PLYs and follows only good captures
• UCI Options: can configure Hash Size, Book, LRM, IID, extensions, the evaluator to use, etc.
• Bugs with draw detection by the 50 move rule (I was doing at 50 PLY), and lots of other small bugs solved

Finally the Negascout code did not improve results at tournaments, so all the Negascout code is commented in the SearchEngine. I’ll continue to investigate.

With this release I include an package to run the program from chess GUIs like Arena, so now it can be included in “official” tournaments.

ELO at tests had a big increase from last version. Now scores over 2330 ELO points at BT2630 test (from the 2100 of Carballo 0.2). Also the positions solved of the “win at chess” test are now 275 of 300 (from the previous 237/300), well, also helped that the EPD parser had a bug and didn’t work well with positions with more than one solution. In LCT II also scores 2300 ELO. All the tests results are in the SVN, at the folder “testresults”.

But at tournament (playing against other java chess engines), the improvement is not so much. Now I think is over BrembroCE, but remains behind Jonathan Pettersson’s Mediocre, Alf and Frank Walter chess engines. I will center the next testing in tournament play.

Play Against Carballo Chess Engine

I’ve been using Opera Mini 4 for 1 year and I prefer it over the Symbian integrated browser because is faster, simpler and smaller. Now Opera announced the avaiability of an Opera Mini 5 Beta. The main new features are:

- Speed Dial with captures of the pages, like in the desktop version. I don’t use Opera for the desktop but the “Speed Dial” plugin for Firefox is one of my favourites. Also Is not very intuitive to edit a dial (pressing 1).
- Tabbed browsing: not very usable, too many clicks to change the tab till I discovered the shortcut (* ->).

Well, it also has touchscreen support but I couldn’t test it in my N95. I didn’t noticed improvements in page rendering: some pages continue to fail (especially with flash), and I need to see them in the Symbian browser.

The only inconvenience over the previous version is that the time to load the application has increased a lot and that is a bit less fluid; let’s see if with the final release this is solved. The beta can be downloaded at:

http://www.opera.com/mini/next