1.g4 opening is losing?

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jp
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Re: A small test...

Post by jp » Mon Feb 10, 2020 2:36 pm

Zenmastur wrote:
Mon Feb 10, 2020 2:23 pm
In this position the win isn't in doubt. Ok, maybe in JP's mind there is some doubt, but for the rest of us it's pretty much a sure thing.
jp & Louis & Uri & Dann are like-minded on that. 8-)

Zenmastur wrote:
Mon Feb 10, 2020 2:28 pm
zullil wrote:
Mon Feb 10, 2020 1:31 pm
I assume he wants a full mating line, preferably one that is at least arguably minimal.
It doesn't have to be exact. Within 4 moves is good enough. You shouldn't have any problems with this as it was meant to test his hardware and analysis skills in combination. Big hardware should have no problems with it.
Or Ovyron could do a quicker test on another example by restricting his engine1 and engine2 to depth 10 or 15. e.g. the position in the other thread where Black gives odds of all his pieces (keeping only Ps), where the minimal mate may be around 15 or 16, but possibly lower (or higher), and SF-dev starts showing non-minimal mate scores for depths 33+.

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Re: A small test...

Post by zullil » Mon Feb 10, 2020 5:42 pm

Zenmastur wrote:
Mon Feb 10, 2020 2:28 pm
zullil wrote:
Mon Feb 10, 2020 1:31 pm
Ovyron wrote:
Mon Feb 10, 2020 12:41 pm
Zenmastur wrote:
Mon Feb 10, 2020 8:52 am
Could you do a small test analysis for us? Something not too difficult like analyze this position to mate:

You mean some mate score as shown by the engine, right? Not the shortest mate, which I don't see the point of doing...

I assume he wants a full mating line, preferably one that is at least arguably minimal.
It doesn't have to be exact. Within 4 moves is good enough. You shouldn't have any problems with this as it was meant to test his hardware and analysis skills in combination. Big hardware should have no problems with it.
I'm seeing Mate-in-35 at this point. No idea if that's minimal.

jp
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Re: 1.g4 opening is losing?

Post by jp » Mon Feb 10, 2020 11:09 pm

Zenmastur wrote:
Mon Feb 10, 2020 12:58 am
While I might entertain arguments about the length of a mate, for me, arguing that I can't produce a proof tree and therefore there is no mate seems utterly ridiculous.
:shock: :shock:
No one ever said "therefore there is no mate". They said if you only have CC games, no matter how much effort went into them, you only have data, not proof.

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Ovyron
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Re: A small test...

Post by Ovyron » Tue Feb 11, 2020 1:48 am

Zenmastur wrote:
Mon Feb 10, 2020 2:23 pm
Lets say if you miss the length by 5 moves or more you get to defend 1.g4 against me and if you are within 4 moves I'll defend 1.g4 against you! But you have to give a complete line to mate so we can check it. Deal?
I can get it exactly, and I can produce a learning file so everyone downloads it and gets the exact mate score if they use the same learning engine. If doing this is what would get you to play 1.g4 against me, sure, can do! :) My analysis methods have never focused on playing the shortest win, but about finding a line that most likely wins, and forcibly win if I'm on a won position. But I know how to get more exact at will, so I'll report my progress about finding the shortest mate in a new thread...

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Re: A small test...

Post by Zenmastur » Tue Feb 11, 2020 2:05 am

Ovyron wrote:
Mon Feb 10, 2020 12:41 pm
Zenmastur wrote:
Mon Feb 10, 2020 8:52 am
Could you do a small test analysis for us? Something not too difficult like analyze this position to mate:

You mean some mate score as shown by the engine, right? Not the shortest mate, which I don't see the point of doing...

So for this I'll be using 2 different engines, instead of some boring Engine 1 and Engine 2 let's nickname them:

Femme Fatale: This engine is really good at finding mates at low depth. However, it'll show some insane lowerbounds, like "+M160", which stands for "I can guarantee to win this position, and I can guarantee to do it on 160 moves or less." That she does, she'll decrease their counter with every move, but not with more depth. But I don't think you'd be happy if I show a mate score of 200 for this, would you?

Harem Girl: This one is the opposite, failing to see mate until it's on her face, choosing to report scores of +132.00 instead. Her problem is that these +132 scores may stay the same after a move, or they may go backwards (like from 132.71 to 132.70), so it's not reliable on finding them. HOWEVER, once she sees the mate she'll show a much better lowerbound, such as +M23 for the same position that Femme Fatale showed +M160. This would be the score that you'd want to backsolve.

For these purposes I'll use Femme Fatale for the white side exclusively. The idea is that she'll be leading the position to a mate score. I'll be using Harem Girl for the black side at the tail of the variations, so she tells us better mate scores (which could be lower than what she shows, but we'd be happy if those are brought to the root.)

SPOILER ALERT - I'm not doing it to completion, just for enough time so it's clear how the procedure works.

Initially, I use Femme Fatale at Depth 32 for the main move, and Depth 22 to get an alternative move. This is important in case her mainline falls below an alternative move, so we're not following the winning line. So I start (I'm snipping the end of the variations for clarity):

32/58 1:47 +9.45 1.Rh8+ Kf7 2.Rf1+ Qf5 3.Rxf5+ Kg6 4.Rg5+ Kf6 5.Bd3 dxe3 6.Rg6+
22/38 0:04 +0.32 1.Bc4 Qxc4 2.Rh8+ Kf7 3.Ne5+ Ke6 4.Nxc4 Rac7 5.bxc3 dxe3 6.Nxe3

I'll be making these first white and black moves that it shows in her PV, so 1.Rh8+ Kf7 are moved.

32/54 1:10 +9.07 2.Rf1+ Qf5 3.Rxf5+ Ke6 4.Re5+ Kd6 5.Bf4 axb5 6.Nxa7
22/39 0:04 +0.35 2.Bc4 dxe3 3.bxc3 Qxc4 4.Ne5+ Ke6 5.Nxc4 Rac7 6.Nxe3

2.Rf1+ Qf5 are moved.

32/57 2:14 +10.66 3.Rxf5+ Ke6 4.Re5+ Kd6 5.Bf4 axb5 6.Nxa7 Rxa7 7.Rxc8

Here 2 minutes / move are deemed too long per node, so I decrease main depth to 31, and the depth of the alternatives to 21.

21/38 0:04 +5.15 3.Bc4+ Kf6 4.Rxf5+ Kxf5 5.Rf8+ Rf7 6.Bxf7 dxe3 7.Bc4+

3.Rxf5 Ke6 are moved.

31/02 0:01 +10.66 4.Re5+ Kd6 5.Bf4 axb5 6.Nxa7 Rxa7 7.Rxc8 Ba5 8.Rxb5+
21/37 0:04 +6.74 4.Rf3 axb5 5.Nxa7 Rxa7 6.Rxc8 Rxa2 7.bxc3 dxe3 8.Rxe3+

And so on...

31/02 0:02 +10.66 5.Bf4 axb5 6.Nxa7 Rxa7 7.Rxc8 Ba5 8.Rxb5+ Kd7 9.Rc4
21/36 0:03 +6.74 5.Rxc8 dxe3 6.Rxe3 Bf6 7.Rd3+ Ke6 8.Nxa7 Rxa7 9.Rc6+
.
.
.
... snip snip...
.
.
.

We need a better 12th.

40/54 0:58 +132.72 12...Ra7 13.Rg5 Kf7 14.Be5 (265.310.352) 4521 TB:2.770.218

31/02 0:00 +M146 13.Rbxd4 Ke6 14.Rd6+ Kf5 15.Rd7 (1.293.266) 2288

So now I'd play Femme Fatale's move into Harem Girl until she shows a better bound, then go back and forward until she shows a mate score for the 9th move, and I go back to the 8th, and so on.

By this point it should be clear what I'm doing. After I'm done Harem Girl would be able to show a mate score from the root position, and since she'd store it on her learning file, she'd show it immediately even after I unload and reload the engine in the GUI.

The reason I have to reach depths below 2 minutes is that to backsolve a score I'd need to at least reach this depth everywhere, which becomes a waste of time with more depth.
I was hoping that this would be a little more straight forward than it turned out to be. But the explanation you provided was helpful in seeing exactly how you go about analyzing a position. It seems sound enough.

The reason I picked a mate instead of some other type of position is there is a clear goal, it has a definite end, and the sub-goals are all pretty straight forward. I figure if you can't drive this position to a near optimal conclusion you also won't be able to drive positions with less well defined goals and end points to near optimal solutions either. For example some positions in your current game.

From your analysis I got this:



Would you say that this is correct?

If so, and this is your finale analysis then I'll post my analysis and then we can compare them and pick them apart.

Regards,

Zenmastur
Only 2 defining forces have ever offered to die for you.....Jesus Christ and the American Soldier. One died for your soul, the other for your freedom.

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Re: 1.g4 opening is losing?

Post by mmt » Tue Feb 11, 2020 2:40 am

In this position, SF 11 with a good percentage of 7-piece tablebases does find a mate at depth 56 in 15 mins. But I don't know in how many moves because I don't have DTM tablebases :)

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Ovyron
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Re: A small test...

Post by Ovyron » Tue Feb 11, 2020 5:23 am

Zenmastur wrote:
Tue Feb 11, 2020 2:05 am
Would you say that this is correct?
No way! I didn't even check any black alternative near the root, so any black move could be better than my line. I was just demonstrating the core of the method, and where it got to after the used time (you can see the search times of the PVs and sum them to know how long it took me to reach this point. After 2 hours of interaction I'd be in a much better place) if how I do it isn't actually relevant and what matters is if I can do it, I'll try to find a shortest mate line ASAP (which will be faster as I don't really have to copy and paste PVs to show them.)

What you saw in that post is how far I get after about 30 minutes of interaction, but I had no reason to continue. If I get to play against your 1.g4 then that's a good reason to continue, so I'll bring in a mate line that hopefully is within 5 moves of the real thing.

jp
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Re: A small test...

Post by jp » Tue Feb 11, 2020 5:42 am

Ovyron wrote:
Tue Feb 11, 2020 5:23 am
Zenmastur wrote:
Tue Feb 11, 2020 2:05 am
If I get to play against your 1.g4 then that's a good reason to continue, so I'll bring in a mate line that hopefully is within 5 moves of the real thing.
Sounds like a deal. 8-)

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Ovyron
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Re: 1.g4 opening is losing?

Post by Ovyron » Tue Feb 11, 2020 6:07 am

I'll do my best! Remember that if I fail I have to lose -- I mean, defend 1.g4 against him! :shock:

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Re: 1.g4 opening is losing?

Post by mmt » Tue Feb 11, 2020 8:17 am

I like how you guys assume I've already lost :mrgreen:

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