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SEE on non-capture moves in main search
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Robert Hyatt



Joined: 27 Feb 2006
Posts: 15869
Location: Birmingham, AL
PostPost subject: Re: SEE on non-capture moves in main search    Posted: Fri Mar 30, 2007 9:27 pm Reply to topic Reply with quote
hgm wrote:
bob wrote:
First, read the following sentence, quoted verbatim from Tord's comments:

=====================================================
"However, among the winning and equal captures, MVV/LVA move ordering performs better than SEE move ordering, which is counter-intuitive to me. "
=====================================================

Now, please point out exactly _where_ I managed to misread something?

So he is not using pure MVV/LVA, as in pure MVV/LVA you would order QxR before PxB, even if the R is defended. But in the latter case QxR is not likely to be a good or equal capture, so it goes in the back with the losing captures, after the (obviously) winning PxB.


Again, read _what_ I wrote. QxR wins a pawn (queen for 2 rooks). That is a winning exchange by SEE. It should _not_ be searched prior to RxN which wins a knight.

Quote:


This repairs the major shortcoming of pure MVV/LVA, and it repairs it much bettwer than pure SEE ordering does. Ordering on SEE-scores only is some 20-30% slower with me than the MVV/SEE/LVA Tord describes.


"slower with me". I am running some tests right now. So far, for my program, this has hurt performance, not helped. More when I have the entire test completed so I can post overall averages...


Quote:


Comparing it with pure MVV/LVA ordering, a you are insistantly doing, is not at all relevant, as no serious engine is using pure MVV/LVA ordering, and it is old hat that it is stupid to order QxR early if you don't know if the Rook is defended.



Can we stop with the blanket statements that are wrong? "no serious engine uses MVV/LVA". Let me name a few, from older to newer:

(1) Belle
(2) chiptest
(3) deep thought
(4) deep blue
(5) dark thought
(6) Hydra

MVV/LVA is the only viable solution when using special-purpose hardware. But plenty of programs have used it (my list above is not complete) with reasonable results. As I mentioned, I produced _real_ data on this comparison about 15 years ago, and SEE only improves on MVV/LVA by 10% if you don't do the prune losing captures trick And it is significantly faster. In fact, it is fast enough to be a "break-even" deal compared to SEE, without the bad capture pruning feature turned on...


Quote:
(Nevertheless microMax still uses pure MVV/LVA, as its 10-character SEE is not significantly faster than a full QS with futility, so SEEing before QSing is mainly a waste of time there.)

To me it seems intuitively clear that an equal QxQ (SEE=0) should be ordered before a winning NxR (SEE=+2). Because in 99% of the cases the equal QxQ of course will also have a QS=2, as the STM will simply follow it up by the NxR. The goo captures don't go away


What if after QxQ, RxQ the NxR is no longer possible because the rook retreated to capture the queen. The best plan, period, is to search the move with the best potential gain. NxR is better than QxQ unless QxQ has a higher SEE score because the queen is undefended...

The other hand-waving doesn't do much to convince me otherwise, because I have tried so many different move ordering ideas over the years, and SEE is the one that keeps working.


[/quote]if you take an even higher piece (MVV!) in an equal capture, as he has to capture back. If he doesn't, he will lose more that the victim of the good captures is worth, so certainly more than its SEE value.[/quote]

You forgot a critical case as I pointed out, making this a false assumption in plenty of cases.

Quote:
And if you go for the crumbs first, the opponent will go berserk with his heavy pieces. The quickest way to prove a winning line (i.e. through the smallest tree) is by annihalating his counter-strike capability first. If you will not try QxQ first, he will certainly try it in the reply, and it can only end worse (as your Queen might be undefended).


I don't buy that either. The queen is not always _the_ piece that is causing difficulty. That is a dynamic characteristic of the position that you are attempting to generalize on and recognize using static criteria. alpha/beta is sensitive to producing scores outside the window as quickly as possible. You seem to be suggesting that playing moves that win more slowly are more efficient, which I don't buy at all.

However, there's apparently little reason to continue down this argument, although I will post my SEE + MVV/LVA results when they are done. Early results were worse, but I am running a lot of positions to be sure.
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Subject Author Date/Time
SEE on non-capture moves in main search Gary Wed Mar 28, 2007 11:25 pm
      Re: SEE on non-capture moves in main search Robert Hyatt Thu Mar 29, 2007 1:17 am
            Re: SEE on non-capture moves in main search Tord Romstad Thu Mar 29, 2007 10:03 am
                  Re: SEE on non-capture moves in main search ed Thu Mar 29, 2007 1:34 pm
                        Re: SEE on non-capture moves in main search Sam Hamilton Fri Mar 30, 2007 12:07 am
                        Re: SEE on non-capture moves in main search Tord Romstad Fri Mar 30, 2007 11:46 am
                  Re: SEE on non-capture moves in main search Robert Hyatt Thu Mar 29, 2007 9:35 pm
                        Re: SEE on non-capture moves in main search H.G.Muller Thu Mar 29, 2007 10:27 pm
                              Re: SEE on non-capture moves in main search Robert Hyatt Fri Mar 30, 2007 12:05 am
                                    Re: SEE on non-capture moves in main search H.G.Muller Fri Mar 30, 2007 6:50 am
                                          Re: SEE on non-capture moves in main search Robert Hyatt Fri Mar 30, 2007 9:27 pm
                                                Re: SEE on non-capture moves in main search Tord Romstad Fri Mar 30, 2007 10:29 pm
                                                      Re: SEE on non-capture moves in main search Robert Hyatt Sun Apr 01, 2007 1:51 am
                                                            Re: SEE on non-capture moves in main search Tord Romstad Sun Apr 01, 2007 7:54 am
                                                                  Re: SEE on non-capture moves in main search Robert Hyatt Mon Apr 02, 2007 1:57 am
                                                            Re: SEE on non-capture moves in main search H.G.Muller Sun Apr 01, 2007 10:22 am
                                                                  Re: SEE on non-capture moves in main search Robert Hyatt Mon Apr 02, 2007 2:05 am
                                                                        Re: SEE on non-capture moves in main search H.G.Muller Mon Apr 02, 2007 12:31 pm
                                                                              Re: SEE on non-capture moves in main search Robert Hyatt Mon Apr 02, 2007 3:56 pm
                                                                                    Re: SEE on non-capture moves in main search Steven Edwards Mon Apr 02, 2007 4:44 pm
                                                                                          Re: SEE on non-capture moves in main search H.G.Muller Mon Apr 02, 2007 4:59 pm
                                                                                          Re: SEE on non-capture moves in main search Robert Hyatt Mon Apr 02, 2007 6:44 pm
                                                                                          Re: SEE on non-capture moves in main search Robert Hyatt Mon Apr 02, 2007 6:40 pm
                                                                                    Re: SEE on non-capture moves in main search H.G.Muller Mon Apr 02, 2007 4:53 pm
                                                Re: SEE on non-capture moves in main search H.G.Muller Sat Mar 31, 2007 8:38 am
                                                      Re: SEE on non-capture moves in main search Robert Hyatt Sun Apr 01, 2007 1:59 am
                                                            Re: SEE on non-capture moves in main search Tord Romstad Sun Apr 01, 2007 7:58 am
                                                                  Re: SEE on non-capture moves in main search Robert Hyatt Mon Apr 02, 2007 3:57 pm
                                                                  Re: SEE on non-capture moves in main search Peter Fendrich Mon Apr 02, 2007 5:19 pm
                                                                        Re: SEE on non-capture moves in main search Robert Hyatt Mon Apr 02, 2007 6:46 pm
                                                                        Re: SEE on non-capture moves in main search Tord Romstad Mon Apr 02, 2007 6:51 pm
                                                                              Re: SEE on non-capture moves in main search Peter Fendrich Mon Apr 02, 2007 7:53 pm
                                                                                    Re: SEE on non-capture moves in main search H.G.Muller Mon Apr 02, 2007 9:01 pm
                                                                                          Re: SEE on non-capture moves in main search Peter Fendrich Mon Apr 02, 2007 9:30 pm
                                                                                          Re: SEE on non-capture moves in main search H.G.Muller Tue Apr 03, 2007 8:46 am
                                                                                          Re: SEE on non-capture moves in main search Peter Fendrich Tue Apr 03, 2007 10:29 am
                                                                                          Re: SEE on non-capture moves in main search Robert Hyatt Tue Apr 03, 2007 9:23 pm
                                                                                          Re: SEE on non-capture moves in main search Tord Romstad Wed Apr 04, 2007 2:38 pm
                                                                                          Re: SEE on non-capture moves in main search Peter Fendrich Wed Apr 04, 2007 7:49 pm
                                                                                          Re: SEE on non-capture moves in main search Tony Tue Apr 03, 2007 10:54 am
                                                                                          Re: SEE on non-capture moves in main search Robert Hyatt Tue Apr 03, 2007 9:24 pm
                                                                                          Re: SEE on non-capture moves in main search H.G.Muller Tue Apr 03, 2007 9:29 pm
                                    Re: SEE on non-capture moves in main search Tord Romstad Fri Mar 30, 2007 11:40 am
                              Re: SEE on non-capture moves in main search Tord Romstad Fri Mar 30, 2007 11:54 am
                                    Re: SEE on non-capture moves in main search H.G.Muller Fri Mar 30, 2007 1:28 pm
                                          Re: SEE on non-capture moves in main search H.G.Muller Fri Mar 30, 2007 4:41 pm
                        Re: SEE on non-capture moves in main search Tord Romstad Fri Mar 30, 2007 11:30 am
                              Re: SEE on non-capture moves in main search Uri Blass Fri Mar 30, 2007 11:50 am
                                    Re: SEE on non-capture moves in main search Tord Romstad Fri Mar 30, 2007 10:32 pm
                              Re: SEE on non-capture moves in main search H.G.Muller Fri Mar 30, 2007 12:16 pm
                              Re: SEE on non-capture moves in main search Robert Hyatt Fri Mar 30, 2007 9:32 pm
                                    Re: SEE on non-capture moves in main search Tord Romstad Fri Mar 30, 2007 10:00 pm
      Re: SEE on non-capture moves in main search Mark Lefler Thu Mar 29, 2007 6:30 am
      Re: SEE on non-capture moves in main search H.G.Muller Thu Mar 29, 2007 9:28 am
            Re: SEE on non-capture moves in main search Tord Romstad Thu Mar 29, 2007 10:13 am
                  Re: SEE on non-capture moves in main search H.G.Muller Thu Mar 29, 2007 12:03 pm
                        Re: SEE on non-capture moves in main search Tord Romstad Thu Mar 29, 2007 12:39 pm
                              Re: SEE on non-capture moves in main search H.G.Muller Thu Mar 29, 2007 2:15 pm
                                    Re: SEE on non-capture moves in main search Zach Wegner Thu Mar 29, 2007 9:10 pm
                  Re: SEE on non-capture moves in main search Steven Edwards Thu Mar 29, 2007 2:18 pm
                  Re: SEE on non-capture moves in main search Rob Sun Apr 01, 2007 6:01 pm
      Re: SEE on non-capture moves in main search Gary Sun Apr 01, 2007 8:26 am
      Re: SEE on non-capture moves in main search Markoff Thu Apr 05, 2007 11:25 pm
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