LCzero sacs a knight for nothing

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George Tsavdaris
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Re: LCzero sacs a knight for nothing

Post by George Tsavdaris » Sat Apr 21, 2018 10:02 am

Laskos wrote: Yes, some sort of list. For ECM200.epd middlegame tactical suite (200 positions), analyzed for 20s/position. At this time control and my hardware, LC0 performs overall (Elo-wise) comparably to GreKo 6.5 2330 Elo CCRL standard A/B engine, which fares much better tactically (but much worse positionally). And it seems on this tactical middlegame suite ID124 is still the best of the nets.

Having watched around 100+ games of ID150+ and ~40 games of ID 156 versus 2100-3100 CCRL ELO opponents, i see that LC0(with that IDs as also with previous) completely outplays positionaly the other engines in many many cases, just to miss in at least 80% of them a tactical hit that either cost LC0 the win or even the draw and it loses.

LC0 is on par i dare to say with Stockfish dev in evaluation, but of course is ultra weak in tactics. It's even better than Stockfish in King attacks as i have seen. In placing its pieces to attack. Not in executing the attack since in that aspect is fails miserably due to bad tactics. The pattern recognition its NNs are offering it to see how to attack the King, seem to be extremely prosperous.


Meanwhile ID160 had a good jump in self-play ELO.
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noobpwnftw
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Re: LCzero sacs a knight for nothing

Post by noobpwnftw » Sat Apr 21, 2018 10:27 am

I think the approach is trying to summarize simulation results, which is good at handling general cases.

Those tactical lines are isolated incidents which it can never solve, while with minimax the search will develop that line deep and fast enough to see it.

It is not like we cannot write better evaluation code, but once a while it turns out that a simplification actually gains ELO because the search will run faster. LC0 is doing the opposite, and people seem to ignore the fact that it's evaluation is just slow, and blame the hardware for poor performance, even with A0's hardware you get some 80k NPS, convert that naively to CPU, 1 TPU ~= 10x 1080TI, one 1080TI ~= 32 CPU cores. so for A0 that's 4*10*32 = 1280 CPU cores.

Given that many CPU cores I'm sure I can get more than +100 ELO against a 64-core SF8 to get that result.

noobpwnftw
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Re: LCzero sacs a knight for nothing

Post by noobpwnftw » Sat Apr 21, 2018 10:46 am

In fact, my test shows that it would only need about 1/3 of A0's hardware performance to get there, not including all the training efforts, now you tell me which is more efficient?

Michel
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Re: LCzero sacs a knight for nothing

Post by Michel » Sat Apr 21, 2018 11:39 am

If the move probabilties are supposed to single out "unclear" moves, then things could work. But I don't really see how the whole updating process would work towards identifying "unclear" moves.
Well we will have to wait to see how good (or bad) LC0 will eventually become at tactics. I am hoping that the majority of chess tactics actually depend on fairly standard patterns and that the NN (value head and policy head) can learn to recognize those patterns. This would be similar to how humans handle tactics.

Recent experiments (by Kai and Killiani) show that the policy network of LC0 is on par with SF at depth 1 (with quiescence search). This might mean that LC0 already statically recognizes some recapture patterns. Unfortunately it may also mean that SF simply prunes too much at depth 1 to be competitive...
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Laskos
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Re: LCzero sacs a knight for nothing

Post by Laskos » Sat Apr 21, 2018 12:12 pm

Michel wrote:
If the move probabilties are supposed to single out "unclear" moves, then things could work. But I don't really see how the whole updating process would work towards identifying "unclear" moves.
Well we will have to wait to see how good (or bad) LC0 will eventually become at tactics. I am hoping that the majority of chess tactics actually depend on fairly standard patterns and that the NN (value head and policy head) can learn to recognize those patterns. This would be similar to how humans handle tactics.

Recent experiments (by Kai and Killiani) show that the policy network of LC0 is on par with SF at depth 1 (with quiescence search). This might mean that LC0 already statically recognizes some recapture patterns. Unfortunately it may also mean that SF simply prunes too much at depth 1 to be competitive...
I don't think SF9 depth=1 is excessively weak and misses much compared to lesser pruning, older engines. An older test showing depth=1 results in RR games from regular openings:

Code: Select all

Rank Name                        ELO   Games   Score   Draws 
   1 Komodo 8                     92    1000     63%     18% 
   2 Houdini 4                    78    1000     61%     26% 
   3 Hannibal 1.4                 56    1000     58%     23% 
   4 SF 14122014                  43    1000     56%     20% 
   5 Hiarcs 14                   -22    1000     47%     16% 
   6 Shredder 6PB (2002)        -302    1000     15%     14% 
Finished match
And IIRC the newer results are not that different.

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Laskos
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Re: LCzero sacs a knight for nothing

Post by Laskos » Sat Apr 21, 2018 12:55 pm

George Tsavdaris wrote:
Laskos wrote: Yes, some sort of list. For ECM200.epd middlegame tactical suite (200 positions), analyzed for 20s/position. At this time control and my hardware, LC0 performs overall (Elo-wise) comparably to GreKo 6.5 2330 Elo CCRL standard A/B engine, which fares much better tactically (but much worse positionally). And it seems on this tactical middlegame suite ID124 is still the best of the nets.

Having watched around 100+ games of ID150+ and ~40 games of ID 156 versus 2100-3100 CCRL ELO opponents, i see that LC0(with that IDs as also with previous) completely outplays positionaly the other engines in many many cases, just to miss in at least 80% of them a tactical hit that either cost LC0 the win or even the draw and it loses.

LC0 is on par i dare to say with Stockfish dev in evaluation, but of course is ultra weak in tactics. It's even better than Stockfish in King attacks as i have seen. In placing its pieces to attack. Not in executing the attack since in that aspect is fails miserably due to bad tactics. The pattern recognition its NNs are offering it to see how to attack the King, seem to be extremely prosperous.


Meanwhile ID160 had a good jump in self-play ELO.
Yes, ID160 seems the strongest (at least in my test). Now I am checking its scaling, seems to scale nicely from 1s/move to 4s/move compared to similar in strength Jabba 1.0 (in my conditions).

syzygy
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Re: LCzero sacs a knight for nothing

Post by syzygy » Sat Apr 21, 2018 1:09 pm

noobpwnftw wrote:In fact, my test shows that it would only need about 1/3 of A0's hardware performance to get there, not including all the training efforts, now you tell me which is more efficient?
The human cost of developing LC zero is zero... Well, more or less :)

Werewolf
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Re: LCzero sacs a knight for nothing

Post by Werewolf » Sat Apr 21, 2018 1:21 pm

Laskos wrote:
George Tsavdaris wrote:
Laskos wrote: Yes, some sort of list. For ECM200.epd middlegame tactical suite (200 positions), analyzed for 20s/position. At this time control and my hardware, LC0 performs overall (Elo-wise) comparably to GreKo 6.5 2330 Elo CCRL standard A/B engine, which fares much better tactically (but much worse positionally). And it seems on this tactical middlegame suite ID124 is still the best of the nets.

Having watched around 100+ games of ID150+ and ~40 games of ID 156 versus 2100-3100 CCRL ELO opponents, i see that LC0(with that IDs as also with previous) completely outplays positionaly the other engines in many many cases, just to miss in at least 80% of them a tactical hit that either cost LC0 the win or even the draw and it loses.

LC0 is on par i dare to say with Stockfish dev in evaluation, but of course is ultra weak in tactics. It's even better than Stockfish in King attacks as i have seen. In placing its pieces to attack. Not in executing the attack since in that aspect is fails miserably due to bad tactics. The pattern recognition its NNs are offering it to see how to attack the King, seem to be extremely prosperous.


Meanwhile ID160 had a good jump in self-play ELO.
Yes, ID160 seems the strongest (at least in my test). Now I am checking its scaling, seems to scale nicely from 1s/move to 4s/move compared to similar in strength Jabba 1.0 (in my conditions).
I'd love to see your tactical results on ID 160.

My own tests are no longer totally negative, but are very mixed.

Below is the "easiest" position in my testsuite, which I've posted many times but LCZero ID 160 still cannot get in 20 minutes.

[pgn] 1.e4 e5 2.Nf3 d6 3.Nc3 g6 4.Bc4 Bg4 5.Ne5 [/pgn]

and yet, curiously it gets the following position which is MUCH harder for alpha betas.


[pgn] 1. d4 d5 2. c4 dxc4 3. Nc3 e5 4. e3 exd4 5. exd4 Nf6 6. Bxc4 Be7 7. Nf3 Nbd7 8. Bxf7+ [/pgn]



This position was a real challenge until around 1993-1995 because dedicateds thought 8.Ng5 was a simpler way to win (it's not) and 8.Bf7 requires seeing quite deeply in one line.

Yet LCZero 160 finds this in 12 seconds!

jdart
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Re: LCzero sacs a knight for nothing

Post by jdart » Sat Apr 21, 2018 4:29 pm

I wonder if some kind of hybrid NN/minimax algorithm might make sense, where the NN would guide the search but the search would validate that the so-called best line is tactically sound? I am not actually an expert in this area. But while A0 is very interesting, in practical terms, on current consumer hardware, it does not seem like pure NN is a promising approach. True, you can throw hardware at it to make it better. But on comparable hardware (dollars or FLOPS or however you want to measure it) Stockfish is still hard for it to beat.

--Jon

noobpwnftw
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Re: LCzero sacs a knight for nothing

Post by noobpwnftw » Sat Apr 21, 2018 5:27 pm

For hybrid approach, I have an idea: couldn't we run some MCTS threads and make use of their simulations for root move ordering? Let's just say if we can feed one GPU with 2 CPU threads, then we have them running independently, from time to time we could reorder root moves by their eval scores scaled to win rate estimation, it may help with favoring moves that score a few centi-pawns less but more favorable in the NN's view.

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