Author: Stephen Ham
Date: 15:59:53 10/18/05
Go up one level in this thread
On October 18, 2005 at 18:15:18, Dann Corbit wrote: >On October 18, 2005 at 17:49:50, Mark R. Anderson wrote: > >>On October 18, 2005 at 15:24:52, Dann Corbit wrote: >> >>>On October 18, 2005 at 15:10:36, Mark R. Anderson wrote: >>> >>>>CCC Friends, >>>> >>>>I have heard that Toga is a Fruit clone. I presume this was done with the >>>>permission of the author, when Fruit was a free engine. So, what is the >>>>difference in style and capabilities between Fruit and Toga? Is Toga a >>>>"tweaked" Fruit, like Uri's Fruit version? >>>> >>>>What makes Toga separate from Fruit? I know from experience that Toga is a good >>>>and strong engine, but the engine it was based on, Fruit, is really a top >>>>engine, so one would expect that. So, I am wondering, why should I have Toga on >>>>my hard drive, if I have a much improved version of the engine it was derived >>>>from (Fruit 2.2). I mean no disrespect to the creator of Toga ... I am just >>>>curious. I have Hiarcs 9, 8, 7, etc, and also Fritz 8, 7, 6, 5, but I only >>>>tend to really play and analyze with the latest versions. So, what has Toga got >>>>that Fruit doesn't? Does it have a different playing style, or is it just >>>>perhaps Fruit 2.1+? >>>> >>>>Thanks for any comments or insight. >>> >>>The license of Fruit 2.1 and earlier clearly allowed GPL modifications of the >>>source code. >>> >>>Hence, there is no problem with the existance of "clones" as long as they >>>publish the modified source code. >>> >>>Thomas Gaksch has made some small changes to the source code that result in >>>different play. From the data I have seen, Toga II 1.0 is stronger than Fruit >>>2.1 but not as strong as Fruit 2.2. >>> >>>At any rate, it will play a bit differently than Fruit does. >>> >>>If you want to know exactly what has been changed, you can do diffs on the >>>source trees. I believe that Mr. Gaksch has also added one new file. >> >>Dann, >> >>Thanks for the info. How about playing style? > >I do not know a clear definition of playing style. If I did know such a >definition, I probably would not be competent enough to comment on it. > >>Tactical strength? > >Very strong -- about as strong as most professional programs > >>Endgame? > >No EGTB or Bitbase files, so it will probably make some endgame mistakes >(actually, I have watched it do so). Not enough to make a significant >difference in playing strength. But I would not use Toga II for endgame >analysis. > >>That's more like what I mean. >> >>Mark Dear Gents, I'm testing Toga II, Shredder 9 and Fruit 2.2 at home. Based upon my very long time-control tournaments and matches, and test positions from my correspondence games, Toga II is stronger than Fruit 2.1, but not as strong as Fruit 2.2 or Shredder. So this confirms what Dann wrote. Regarding style, I see that Toga II and Shredder 9 find tactical shots fastest and they accordingly play in a more aggressive style than Fruit 2.2. I'm really impressed with Fruit 2.2. It will indeed find tactical shots, but takes longer to find them than Shredder 9 or Toga II. Fruit 2.2 plays in a steady but generally straight-foward style. While it's not "positional", it's certainly not naturally agressive. So if given enough time to find tactical shots, it will play them. In the endgame, I'm impressed with Fruit 2.2. Again, while it doesn't have a dramatic/dynamic style of play in the middle game (it's a little dull), it also seems to play a relatively risk avoiding endgame. Regardless, it's an effective and efficient player, even if its moves seem dull. Shredder 9 is also a strong endgame player and has some advantage due to EGTBs. But Shredder has a more dynamic syle in the endgame too. Generally, these engines are probably equally good endgame players, but still quite different stylistically. I'm investigating a position now where neither Shredder nor Fruit 2.2 select the same candidate moves, and their solutions are entirely different. I'm giving each of them 24-hours to examine the position. Then I'll give each of the engines the PV from the other, to see if they find each other's solution, and how long they take. For me, the biggest advantage of Fruit 2.2 over Shredder 9 is that Shredder has a very "optimistic" (read: wildly inaccurate) evaluation function. Dead equal positions are sometimes assessed by Shredder as being wins. And Shredder will flip back and forth in dynamic positions regarding who has an advantage. Fruit 2.2, however, has a relatively accurate evaluation, superior to Toga's as well. Since Fruit 2.2 isn't a naturally dynamic player, some claim that it's positional. I don't find that to be true at all. Instead, it's just rock-solid with no clear weaknesses. I think Hiarcs 9 and Pro-Deo are the best positional engines, IMHO, but they get outsearched in dynamic positions. That said, I've played long time-control matches and games with the three, being careful to follow Uri's advice to add other engines to the mix. So I added Hiarcs 9 and Junior 9. While each CB engine has its own book, I have none for Toga II and Fruit 2.2 when playing in a CB GUI. So I gave Toga II a book a created from my correspondence games, including my TNs and my private analysis. Fruit has played with either a "solid" Fritz 7 book or Nimzo 7.32 (I'm trying to find which is more compatible). In general, the results show Shredder 9 and Fruit 2.2 on top, with a very slight edge to Shredder. Toga II is often close behind, while Hiarcs and Junior always finish on the bottom. I think Junior is hurt by a bad book that I manually fix and update after each loss. The neat thing about Shredder 9 and Fruit 2.2 is they are the only engines I've seen that can still win from bad positions by outplaying Junior and Hiarcs. Sure, other strong engines can outplay and defeat weaker engines from bad positions. But Junior 9 and Hiarcs 9 are already very strong. But sometimes, Fruit or Shredder will make one bad move that gets them into trouble. But they sometimes are able to still win from bad positions - which I find impressive. All the best, Steve
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