Glaurung 0.1.6
Posted: 21 Jan 2005, 22:18The source code and Mac OS X executable for Glaurung 0.1.6 is now available for download from the Glaurung home page. A Windows executable will follow as soon as Dann or some Windows compiler guru has sent it to me.
Glaurung 0.1.6 contains several improvements compared to 0.1.5. The most important changes are found in the evaluation. First of all, Glaurung now has a rather complicated and expensive king safety eval. This slows the engine down by about 30% in the middle game, but I still think it is an improvement compared to the very primitive king safety found in 0.1.5. There are also numerous other new terms in the evaluation, including a bishop pair bonus and a simple outpost square eval. I have also made some changes, additions and bug fixes in the search. The most important is the introduction of a new pruning system for which I currently use the unattractive name "repeated probably fail low pruning". A better name is obviously needed.
I regret to inform that the infamous "mate in 1" and "0.00" bugs are still there in 0.1.6. I planned to look at these, but simply forgot them in the end. I hope to finally address them in the next version.
How much stronger is 0.1.6 compared to 0.1.5? I don't know yet. My gut feeling is that it will score slightly better against stronger opponents, perhaps slightly worse against weaker opponents, and that the net effect will be a small plus (perhaps 0-30 Elo points). More importantly, however, the new version has a much more aggressive and interesting style of play. It produces lots of sharp games, and frequently sacrifices material for an attack.
Tord
Glaurung 0.1.6 contains several improvements compared to 0.1.5. The most important changes are found in the evaluation. First of all, Glaurung now has a rather complicated and expensive king safety eval. This slows the engine down by about 30% in the middle game, but I still think it is an improvement compared to the very primitive king safety found in 0.1.5. There are also numerous other new terms in the evaluation, including a bishop pair bonus and a simple outpost square eval. I have also made some changes, additions and bug fixes in the search. The most important is the introduction of a new pruning system for which I currently use the unattractive name "repeated probably fail low pruning". A better name is obviously needed.
I regret to inform that the infamous "mate in 1" and "0.00" bugs are still there in 0.1.6. I planned to look at these, but simply forgot them in the end. I hope to finally address them in the next version.
How much stronger is 0.1.6 compared to 0.1.5? I don't know yet. My gut feeling is that it will score slightly better against stronger opponents, perhaps slightly worse against weaker opponents, and that the net effect will be a small plus (perhaps 0-30 Elo points). More importantly, however, the new version has a much more aggressive and interesting style of play. It produces lots of sharp games, and frequently sacrifices material for an attack.
Tord
