1.g4 opening is losing?

[jp]

I like how you guys assume I've already lost

No, we still demand you draw. If you draw with White, we want to see the next White win.

[Ovyron]

Your draw would just look more and more impressive over time! In my game against Harvey I was seeing -2.80 positions that white could draw, if I thought you were already lost I'd be playing my moves instantly, but if there's someone aware about your drawing chances, it's me. I WAS ON YOUR SHOES!

Anyway, solving Zenmastur's game is taking longer than expected, what is this?

[d]8/r2k2p1/8/bR6/2R2B2/3P4/PP6/2K5 b - -

"Harem Girl"

40/51 1:35 +132.73 42...Bc7 43.Rxc7+ Rxc7+ 44.Bxc7 Kxc7 45.Rg5 g6 46.Rxg6 Kb7 47.Rb6+ Kc7 48.b4 Kc8 (457.543.715) 4773 TB:1.873.762
41/53 1:38 +M63-- 42...Bc7 43.Rxc7+ (472.924.365) 4782 TB:1.928.314
41/53 1:41 +M54-- 42...Bc7 43.Rxc7+ (489.234.969) 4822 TB:1.953.261
41/53 1:52 +M40-- 42...Bc7 43.Rxc7+ (560.258.410) 4987 TB:3.856.879
41/53 2:07 +M25 42...Bd8 43.Rd5+ Ke8 44.Re4+ Kf7 45.Rxd8 Rb7 46.Kb1 (664.963.639) 5228 TB:5.283.860
41/53 2:07 +M25 42...Bd8 43.Rd5+ Ke8 44.Re4+ Kf7 45.Rxd8 Rb7 46.Kb1 (664.963.835) 5228 TB:5.283.860
42/59 2:28 +M34++ 42...Ke6 (801.910.850) 5391 TB:7.141.423
42/59 2:36 +M43++ 42...Ke6 (846.313.567) 5407 TB:7.397.678
42/59 2:47 +M26 42...Ke6 43.Rc6+ Kd7 44.Rc4 (905.209.767) 5410 TB:7.666.246
42/59 2:47 +M26 42...Ke6 43.Rc6+ Kd7 44.Rc4 (905.209.856) 5410 TB:7.666.246
43/41 2:54 +M35++ 42...Ra6 (947.795.506) 5418 TB:7.939.881
43/41 2:56 +M44++ 42...Ra6 (953.178.106) 5415 TB:8.006.254
43/41 2:56 +M57++ 42...Ra6 (955.691.123) 5414 TB:8.015.887
43/41 2:57 +132.69++ 42...Ra6 (960.656.167) 5413 TB:8.036.922
43/41 3:00 +132.47++ 42...Ra6 (977.615.913) 5412 TB:8.128.563
43/43 3:20 +132.17++ 42...Ra6 (1.078.234.118) 5382 TB:8.998.189
43/65 4:45 +131.79++ 42...Ke6 (1.519.225.024) 5328 TB:11.701.221
43/65 4:47 +130.97++ 42...Ke6 (1.532.196.502) 5322 TB:11.776.257
43/65 4:48 +129.50++ 42...Ke6 (1.533.220.598) 5322 TB:11.786.916
43/65 4:48 +128.66++ 42...Ke6 (1.533.708.362) 5322 TB:11.792.445
43/65 4:48 +74.02++ 42...Ke6 (1.534.031.865) 5321 TB:11.796.172
43/65 4:48 +70.58++ 42...Ke6 (1.534.549.880) 5321 TB:11.798.438
43/65 4:48 +68.85++ 42...Ke6 (1.535.218.422) 5321 TB:11.801.587
43/65 4:48 +66.66++ 42...Ke6 (1.536.943.596) 5320 TB:11.809.486
43/65 4:49 +63.98++ 42...Ke6 (1.538.815.754) 5319 TB:11.820.229
43/65 4:50 +60.62++ 42...Ke6 (1.542.428.498) 5317 TB:11.836.654
43/65 4:50 +56.39++ 42...Ke6 (1.544.255.091) 5316 TB:11.844.292
43/65 4:51 +51.08++ 42...Ke6 (1.547.109.158) 5316 TB:11.863.363
43/65 4:51 +43.60++ 42...Ke6 (1.549.194.193) 5315 TB:11.882.361
43/65 4:52 +34.43++ 42...Ke6 (1.553.371.505) 5313 TB:11.905.751
43/65 4:52 +24.00++ 42...Ke6 (1.554.920.967) 5313 TB:11.909.412
43/65 5:04 +10.93++ 42...Ke6 (1.613.237.024) 5291 TB:12.100.778
43/65 5:35 +10.93 42...Ke6 (1.752.766.644) 5221 TB:13.160.069

Finds the mate in 26, I let it run more to see if it finds a faster mate, instead it now thinks white advantage falls down to +10 pawns?? I've never seen anything like this before...

[zullil]

Your draw would just look more and more impressive over time! In my game against Harvey I was seeing -2.80 positions that white could draw, if I thought you were already lost I'd be playing my moves instantly, but if there's someone aware about your drawing chances, it's me. I WAS ON YOUR SHOES!

Anyway, solving Zenmastur's game is taking longer than expected, what is this?

[d]8/r2k2p1/8/bR6/2R2B2/3P4/PP6/2K5 b - -

"Harem Girl"

40/51 1:35 +132.73 42...Bc7 43.Rxc7+ Rxc7+ 44.Bxc7 Kxc7 45.Rg5 g6 46.Rxg6 Kb7 47.Rb6+ Kc7 48.b4 Kc8 (457.543.715) 4773 TB:1.873.762
41/53 1:38 +M63-- 42...Bc7 43.Rxc7+ (472.924.365) 4782 TB:1.928.314
41/53 1:41 +M54-- 42...Bc7 43.Rxc7+ (489.234.969) 4822 TB:1.953.261
41/53 1:52 +M40-- 42...Bc7 43.Rxc7+ (560.258.410) 4987 TB:3.856.879
41/53 2:07 +M25 42...Bd8 43.Rd5+ Ke8 44.Re4+ Kf7 45.Rxd8 Rb7 46.Kb1 (664.963.639) 5228 TB:5.283.860
41/53 2:07 +M25 42...Bd8 43.Rd5+ Ke8 44.Re4+ Kf7 45.Rxd8 Rb7 46.Kb1 (664.963.835) 5228 TB:5.283.860
42/59 2:28 +M34++ 42...Ke6 (801.910.850) 5391 TB:7.141.423
42/59 2:36 +M43++ 42...Ke6 (846.313.567) 5407 TB:7.397.678
42/59 2:47 +M26 42...Ke6 43.Rc6+ Kd7 44.Rc4 (905.209.767) 5410 TB:7.666.246
42/59 2:47 +M26 42...Ke6 43.Rc6+ Kd7 44.Rc4 (905.209.856) 5410 TB:7.666.246
43/41 2:54 +M35++ 42...Ra6 (947.795.506) 5418 TB:7.939.881
43/41 2:56 +M44++ 42...Ra6 (953.178.106) 5415 TB:8.006.254
43/41 2:56 +M57++ 42...Ra6 (955.691.123) 5414 TB:8.015.887
43/41 2:57 +132.69++ 42...Ra6 (960.656.167) 5413 TB:8.036.922
43/41 3:00 +132.47++ 42...Ra6 (977.615.913) 5412 TB:8.128.563
43/43 3:20 +132.17++ 42...Ra6 (1.078.234.118) 5382 TB:8.998.189
43/65 4:45 +131.79++ 42...Ke6 (1.519.225.024) 5328 TB:11.701.221
43/65 4:47 +130.97++ 42...Ke6 (1.532.196.502) 5322 TB:11.776.257
43/65 4:48 +129.50++ 42...Ke6 (1.533.220.598) 5322 TB:11.786.916
43/65 4:48 +128.66++ 42...Ke6 (1.533.708.362) 5322 TB:11.792.445
43/65 4:48 +74.02++ 42...Ke6 (1.534.031.865) 5321 TB:11.796.172
43/65 4:48 +70.58++ 42...Ke6 (1.534.549.880) 5321 TB:11.798.438
43/65 4:48 +68.85++ 42...Ke6 (1.535.218.422) 5321 TB:11.801.587
43/65 4:48 +66.66++ 42...Ke6 (1.536.943.596) 5320 TB:11.809.486
43/65 4:49 +63.98++ 42...Ke6 (1.538.815.754) 5319 TB:11.820.229
43/65 4:50 +60.62++ 42...Ke6 (1.542.428.498) 5317 TB:11.836.654
43/65 4:50 +56.39++ 42...Ke6 (1.544.255.091) 5316 TB:11.844.292
43/65 4:51 +51.08++ 42...Ke6 (1.547.109.158) 5316 TB:11.863.363
43/65 4:51 +43.60++ 42...Ke6 (1.549.194.193) 5315 TB:11.882.361
43/65 4:52 +34.43++ 42...Ke6 (1.553.371.505) 5313 TB:11.905.751
43/65 4:52 +24.00++ 42...Ke6 (1.554.920.967) 5313 TB:11.909.412
43/65 5:04 +10.93++ 42...Ke6 (1.613.237.024) 5291 TB:12.100.778
43/65 5:35 +10.93 42...Ke6 (1.752.766.644) 5221 TB:13.160.069

Finds the mate in 26, I let it run more to see if it finds a faster mate, instead it now thinks white advantage falls down to +10 pawns?? I've never seen anything like this before...

The engine is failing-high? It found a Mate-in-26, and then discovered that the line is in error, and that Black can refute it.

[fastgm]

Could you do a small test analysis for us? Something not too difficult like analyze this position to mate:

[d]2b3k1/r2r2p1/p1N1q3/1B6/3p4/2b1B2R/PPP5/2K4R w - - 0 36

No outside help please!

No, it's not some trick position if that's what you are wondering. If I recall, when I had a machine that was about twice as fast as yours I could do mates in 30 no problem. I hit more resistance when I got to a mate in 35. And Mates in 40 were difficult and time consuming to produce. So, I figure somewhere in this range should stress your hardware a fair amount. If your analysis algorithm is as good as you claim this position shouldn't be much of a problem for you. AB engines excel at this type of positions, especially programs like SF. If on the other hand it's too much for your hardware (it's mainly a hardware test) and your analysis is less than stellar then you may have problems calculating it all the way to mate. So, it's not meant to be so hard that you can't do it just hard enough so that your hardware by itself probably won't get you there. Or so my theory says. Then depending on how much or little you struggle with it will give you an idea of if you need new hardware or a new analysis algorithm or neither or both. This shouldn't take that much time if you are as efficient as you say you are.

When I'm analyzing, I don't try to be efficient for the most part. I like chasing positions all the way to mate if it's within the capabilities of the hardware I'm running on. Even if it takes a lot more time to do that than just finding a move that is “good enough”. A failing of mine that I fully recognize. I try to avoid it when playing CC games but sometimes the urge to find the best move is too strong.

And, you are right my algorithm for finding the best move is much simpler than yours.

Regards,

Zenmastur

My solution is mate in 30 moves.

[Ovyron]

No, the line is a mate in 26 or less, the engine loses sight of this and the best line it can find is a +10 advantage, but after forcing the line it does find the mate again, and all is well, but time is lost having to play the moves in positions where one expected that more depth would show a more accurate mate score.

I have yet to see a position where a Mate is found on a position where there's no mate.

[zullil]

No, the line is a mate in 26 or less, the engine loses sight of this and the best line it can find is a +10 advantage, but after forcing the line it does find the mate again, and all is well, but time is lost having to play the moves in positions where one expected that more depth would show a more accurate mate score.

I have yet to see a position where a Mate is found on a position where there's no mate.

No line appears in your engine output. All I see for the Mate-in-26 is a four-move PV. How do you know what line to force if you don't know the line that is the engine has called Mate-in-26?

[jp]

I have yet to see a position where a Mate is found on a position where there's no mate.

So when an engine shows mate in 30, and this blows out to mate in 50, etc., you believe it's always engine "forgetting" rather than engine mistake?

[Ovyron]

No line appears in your engine output. All I see for the Mate-in-26 is a four-move PV. How do you know what line to force if you don't know the line that is the engine has called Mate-in-26?

I'm using two engines. The other one knows a line that mates at all times (though not the fastest mate, just the easiest mate to find), so I feed the mating moves to this one. The difference is that this one has learning, the mating one doesn't, so eventually this one would learn a mate score and be able to show it from the root (I'm making it show mate scores closer and closer to the root) while the mating one would always have a mate outside of its horizon from the root, because of the depths I can reach.

[Ovyron]

So when an engine shows mate in 30, and this blows out to mate in 50, etc., you believe it's always engine "forgetting" rather than engine mistake?

I've never seen a mate in 30 reported when it was impossible to mate this fast, have you?

[jp]

I don't know. I hope not! That's the open question.

Sometimes SF makes the mate announcement and then calculates longer and makes a longer mate announcement or retracts altogether. It must raise some doubt. We need to capture examples to look at.

I also wonder when it gives a mate announcement with a mate line that is apparently "wrong" (White and Black trade suboptimal moves). See here: http://talkchess.com/forum3/viewtopic.p ... 94#p829094.

It's what we want when an engine updates its mate announcement to a quicker mate, but if that means it found better moves for the mating side, why would it be impossible for it also to find better moves for the defending side (leading to a slower mate) -- unless it becomes near-exhaustive in analyzing defending moves once it thinks there's a mate?