Search found 3561 matches

by lkaufman
Wed Mar 02, 2011 4:23 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Why are the Ippo derivative stronger than Stockfish?
Replies: 77
Views: 36100

Re: Why are the Ippo derivative stronger than Stockfish?

The idea itself is not new of course. It is about avoiding stand pat in qsearch when the side to move is under serious threat, but the static evaluation is still above scout. Upon entering search() instead of classical int search(int depth, int scout) { if (depth < ONE_PLY) ...
by lkaufman
Mon Feb 28, 2011 4:40 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Why are the Ippo derivative stronger than Stockfish?
Replies: 77
Views: 36100

Re: Why are the Ippo derivative stronger than Stockfish?

1. optimized - yes, there are speed optimizations all over the place. But they give at most 10-12% speedup over latest Ivanhoes (I have not measured anything, it is just my upper-bound guesstimate). 2. improved - yes, in almost all areas. What is different you ask? Well, material balance, rook/quee...
by lkaufman
Sat Feb 26, 2011 3:29 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Why are the Ippo derivative stronger than Stockfish?
Replies: 77
Views: 36100

Re: Why are the Ippo derivative stronger than Stockfish?

I would feel very uncomfortable revealing in public what I have learned from H1.5... Just give appropriate credit in the next Critter release, for example "without ideas obtained by disassembling Houdini 1.5 this Critter version would not nearly have been as strong" . Robert But he said that what h...
by lkaufman
Fri Feb 25, 2011 8:07 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Why are the Ippo derivative stronger than Stockfish?
Replies: 77
Views: 36100

Re: Why are the Ippo derivative stronger than Stockfish?

I would feel very uncomfortable revealing in public what I have learned from H1.5, but take my word - almost all of the improvements are very IPPO specific and are not applicable to neither SF, Critter nor Komodo. And some of them we already use and are not that original... e.g. rewarding safe quee...
by lkaufman
Fri Feb 25, 2011 7:28 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Why are the Ippo derivative stronger than Stockfish?
Replies: 77
Views: 36100

Re: Why are the Ippo derivative stronger than Stockfish?

An interesting question is what would happen if someone ported the SF eval to an IPP* derivative or the IPP* eval to SF, with appropriate changes to scale so margins are valid. Has anyone done so? Any opinions on what would happen in each of these two cases? I think you are the man who should know,...
by lkaufman
Fri Feb 25, 2011 6:44 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Why are the Ippo derivative stronger than Stockfish?
Replies: 77
Views: 36100

Re: Why are the Ippo derivative stronger than Stockfish?

I don't agree. Houdini 1.03 _could be_ more or less Ippo cleaned up and refined, perhaps throwing in some SF stuff. But Houdini 1.5 has some new tricks in IMHO, otherwise you cannot get 70 ELO jump only fine tuning an engine that, by the way, is already very well tuned. I agree completely about Hou...
by lkaufman
Fri Feb 25, 2011 5:44 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Why are the Ippo derivative stronger than Stockfish?
Replies: 77
Views: 36100

Re: Why are the Ippo derivative stronger than Stockfish?

No, I wasn't asking why we haven't (yet) passed SF, I want to know why passing SF won't make us #1! Sorry but you have a bit of confusion: #1 is currenty houdini not ippo and houdini is 60-70 ELO far away....so I think you have to wait for someone to disassemble Houdini for you and reveals the coup...
by lkaufman
Fri Feb 25, 2011 5:16 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Why are the Ippo derivative stronger than Stockfish?
Replies: 77
Views: 36100

Re: Why are the Ippo derivative stronger than Stockfish?

[quote="mcostalba The ELO difference between SF and Ippo should be around 20 ELO or less. You cannot build up a "theory" out of such a small difference: anything can account for that, few tweaks or few slightly differences are enough and we have much more then slightly differences bewteen Ippo and S...
by lkaufman
Fri Feb 25, 2011 3:20 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Why are the Ippo derivative stronger than Stockfish?
Replies: 77
Views: 36100

Re: Why are the Ippo derivative stronger than Stockfish?

Their search algorithms still differ a lot. IPP* has different pruning rules close to the leaves compared to Stockfish. You can't just blindly copy Rule X from IPP* to SF. The search is one picture. And we don't want to copy the whole search, it would just be pointless. Anyway we got a lot of good ...
by lkaufman
Thu Feb 24, 2011 1:32 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Why are the Ippo derivative stronger than Stockfish?
Replies: 77
Views: 36100

Why are the Ippo derivative stronger than Stockfish?

It seems to me that both the Ippo family programs and SF use many similar ideas, and both are extremely well written and fast programs. Moreover SF had access to the Ippo open-source code for a long time now, and yet despite huge progress it still lacks behind all of these programs, though the gap i...