Thermography
-
Gérard TAILLE
- Gosei
- Posts: 1346
- Joined: Sun Aug 23, 2020 2:47 am
- Rank: 1d
- GD Posts: 0
- Has thanked: 21 times
- Been thanked: 57 times
Thermography
I begin to study thermography.
On the first examples I studied, thermograhy allowed me to have a better understanding concerning the value of a local area depending of the temperature of the environment. Really interesting indeed.
In the other hand I found examples in which I failed to find a good help from thermography and I wondering if my analysis was correct.
Black to move In the diagramm above, hesitating between "a" and "b" I tried to see if thermography can help me.
I calculated the two thermographs of the local area in the upper part of the board, under the two possibilities for black. Unfortunetly the thermographs associated to a black move at "a" and a black move at "b" seems identical. Is it true ?
In addition I built the other following diagram with the same temperature for the environment:
Black to move Maybe I am wrong but in the first diagram you must play "a" and in the second you must play "b".
Can thermography help to resolve thses two situations?
Thank you in advance for helping me.
On the first examples I studied, thermograhy allowed me to have a better understanding concerning the value of a local area depending of the temperature of the environment. Really interesting indeed.
In the other hand I found examples in which I failed to find a good help from thermography and I wondering if my analysis was correct.
Black to move In the diagramm above, hesitating between "a" and "b" I tried to see if thermography can help me.
I calculated the two thermographs of the local area in the upper part of the board, under the two possibilities for black. Unfortunetly the thermographs associated to a black move at "a" and a black move at "b" seems identical. Is it true ?
In addition I built the other following diagram with the same temperature for the environment:
Black to move Maybe I am wrong but in the first diagram you must play "a" and in the second you must play "b".
Can thermography help to resolve thses two situations?
Thank you in advance for helping me.
-
Bill Spight
- Honinbo
- Posts: 10905
- Joined: Wed Apr 21, 2010 1:24 pm
- Has thanked: 3651 times
- Been thanked: 3373 times
Re: Thermography
There is only one thermograph for the top side. (Edit: Oh, it's not just the top side, because White has only one eye on the right side.) It may well be that Black should normally play at a and b at different temperatures. Which player is to move is not a condition of the thermograph.Gérard TAILLE wrote:I begin to study thermography.
On the first examples I studied, thermograhy allowed me to have a better understanding concerning the value of a local area depending of the temperature of the environment. Really interesting indeed.
In the other hand I found examples in which I failed to find a good help from thermography and I wondering if my analysis was correct.
Black to move In the diagramm above, hesitating between "a" and "b" I tried to see if thermography can help me.
I calculated the two thermographs of the local area in the upper part of the board, under the two possibilities for black. Unfortunetly the thermographs associated to a black move at "a" and a black move at "b" seems identical. Is it true ?
What you have are two different whole board positions, each at temperature 0. It is probably easier to figure out correct play than to calculate the thermographs for each board.In addition I built the other following diagram with the same temperature for the environment:
Black to move Maybe I am wrong but in the first diagram you must play "a" and in the second you must play "b".
Can thermography help to resolve thses two situations?
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.
-
Gérard TAILLE
- Gosei
- Posts: 1346
- Joined: Sun Aug 23, 2020 2:47 am
- Rank: 1d
- GD Posts: 0
- Has thanked: 21 times
- Been thanked: 57 times
Re: Thermography
Oops now I am lost.Bill Spight wrote: What you have are two different whole board positions, each at temperature 0.
Lets go slowly by considering only the first diagram
Black to play I see three local areas.
The area A for which I hesitate between the three moves marked "a"
The area B, quite simple, for which the gote move at "b" has a miai value of 2.5
The area C, also quite simple, for which the gote move at "c" has a miai value of 1
The area A is a little difficult to evaluate at least because I see three possible moves.
Let's call the areas B and C the environment.
My understanding was that the temperature of the environment is equal here to 2.5 (max of miai values in the environment) but when you mention temperature 0 it seems something is wrong in my head. Can you clarify this point Bill?
In order to know if I should play in area A rather than in the environment (B + C) I have first to calculate the miai value of area A.
Seeing that the ogeima move gains between 2.5 and 3 points, without knowing the exact value of the miai value, I know its value is greater or equal to 2.5 and I conclude it is a good idea to begin by a move in area A.
Before going further with the different possibilities for black in area A, is the beginning of the reasonning correct?
-
Bill Spight
- Honinbo
- Posts: 10905
- Joined: Wed Apr 21, 2010 1:24 pm
- Has thanked: 3651 times
- Been thanked: 3373 times
Re: Thermography
OK. Then we regard each of the moves in the top as sente, since they threaten to kill White. If White dies, the other areas of the board become moot, so they are not independent. However, we can get around that by assigning the value if Black kills as BIG. I.e., we simply assume that White must answer Black's threat and do not worry about the details. Since we are using the thermograph for heuristics, that's good enough, in general.Gérard TAILLE wrote:Oops now I am lost.Bill Spight wrote: What you have are two different whole board positions, each at temperature 0.
Lets go slowly by considering only the first diagram
Black to play I see three local areas.
The area A for which I hesitate between the three moves marked "a"
The area B, quite simple, for which the gote move at "b" has a miai value of 2.5
The area C, also quite simple, for which the gote move at "c" has a miai value of 1
The area A is a little difficult to evaluate at least because I see three possible moves.
Let's call the areas B and C the environment.
Now let's look at the right side of the thermograph, when White plays first. (White is associated with Right and Black with Left. Since Black scores are positive, this reverses the numbering of the x-axis that we learned in school. A quirk of combinatorial game theory (CGT).)
Black to play plays the hane-and-connect of
White to play plays the hane at
The position after
But White has another plausible play instead of
If White plays
What about the thermograph of the resulting position?
For the left wall of the thermograph after the marked stones have been played,
Now, that fact was probably obvious, but we can demonstrate it as shown.
Actually, once we know that the result of allowing Black two moves in a row in the top is BIG, we know that Black can play there with sente. The miai value is the gain for White of playing the reverse sente. The gain for Black's first play is BIG, which is all we need to know for comparison. And by inspection we know that Black does not have to preserve a play in the top as a ko threat.In order to know if I should play in area A rather than in the environment (B + C) I have first to calculate the miai value of area A.
More later.
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.
-
Gérard TAILLE
- Gosei
- Posts: 1346
- Joined: Sun Aug 23, 2020 2:47 am
- Rank: 1d
- GD Posts: 0
- Has thanked: 21 times
- Been thanked: 57 times
Re: Thermography
In order to talk about thermograph let's me verify my understanding is correct:
Let's assume the best sequence for black is the sente following sequence:
and let's suppose the best sequence for white is the gote move:
Is the following thermograph correct with this assumption?
Let's assume the best sequence for black is the sente following sequence:
and let's suppose the best sequence for white is the gote move:
Is the following thermograph correct with this assumption?
- Attachments
-
- t1.png (6.02 KiB) Viewed 118896 times
-
Bill Spight
- Honinbo
- Posts: 10905
- Joined: Wed Apr 21, 2010 1:24 pm
- Has thanked: 3651 times
- Been thanked: 3373 times
Re: Thermography
OK. To continue, let's look at Black's play on the top. We already know that Black plays with sente.
First let's look at Black's crawl and White's block. At first blush, it looks like what is left is a double hane-and-connect, which is worth -5, with Black continuing at or below temperature 1. But looking a bit deeper, as I believe you have, that is not the case.
OC, if White plays first the local score is -6, as expected.
The local score is not -4. Why? Because of the follow-up at a.
White to play can play
, for a local score of -3. What if Black plays first?
If Black plays
White can make a ko with
. The result will depend upon the ko threat situation and the rules.
Now, Professor Berlekamp developed komaster theory, which makes certain assumptions about who can win the ko and how, in the 1980s, and first published about it in Games of No Chance (MSRI, 1996). For non-komaster situations, Berlekamp, Bill Fraser, and I developed a theory of a Neutral Threat Environment (NTE) in the early 2000s, and I first published about it in LNCS 2883: Computers and Games (Springer, 2003). AFAICT, none of these ideas has been adopted by professional go players.
The traditional assumption, as may be inferred from the texts, is that there are no ko threats that are not shown. Assuming no ko threats, White cannot afford to make the ko, as Black kills White if she wins the ko.
If we assume that there are no ko threats, the evaluation depends upon the number of dame White has.
Again,
-
form a unit. The local score is +2. So the count before
or
is -½ and the gain for each player is 2½.
Backing up then, to before the hane-and-connect, White's hane-and-connect moves to a local score of -6, and Black's hane-and-connect moves to a count of -½ at or above temperature 2½, we get a count of -3¼ with a move gaining 2¾. And backing up again to the original position (with no dame), we get a count of -3¼ and a gain for the reverse sente of 4¾.
-
form a unit.
and
are miai. The local score is -3, the same as when White plays first.
Backing up to before the hane-and-connect, the count is -4½ and each play gains 1½.
Edit: And backing up to the original position, the count is -4½ and White's reverse sente gains 3½.
That evaluation will be true with more dame, OC.
Going back to the board as given:
Since the b and c regions involve White dame, we cannot just assume that they are independent of the top region.
More later.
First let's look at Black's crawl and White's block. At first blush, it looks like what is left is a double hane-and-connect, which is worth -5, with Black continuing at or below temperature 1. But looking a bit deeper, as I believe you have, that is not the case.
OC, if White plays first the local score is -6, as expected.
The local score is not -4. Why? Because of the follow-up at a.
White to play can play
If Black plays
Now, Professor Berlekamp developed komaster theory, which makes certain assumptions about who can win the ko and how, in the 1980s, and first published about it in Games of No Chance (MSRI, 1996). For non-komaster situations, Berlekamp, Bill Fraser, and I developed a theory of a Neutral Threat Environment (NTE) in the early 2000s, and I first published about it in LNCS 2883: Computers and Games (Springer, 2003). AFAICT, none of these ideas has been adopted by professional go players.
The traditional assumption, as may be inferred from the texts, is that there are no ko threats that are not shown. Assuming no ko threats, White cannot afford to make the ko, as Black kills White if she wins the ko.
If we assume that there are no ko threats, the evaluation depends upon the number of dame White has.
Again,
Backing up then, to before the hane-and-connect, White's hane-and-connect moves to a local score of -6, and Black's hane-and-connect moves to a count of -½ at or above temperature 2½, we get a count of -3¼ with a move gaining 2¾. And backing up again to the original position (with no dame), we get a count of -3¼ and a gain for the reverse sente of 4¾.
Backing up to before the hane-and-connect, the count is -4½ and each play gains 1½.
Edit: And backing up to the original position, the count is -4½ and White's reverse sente gains 3½.
That evaluation will be true with more dame, OC.
Going back to the board as given:
Since the b and c regions involve White dame, we cannot just assume that they are independent of the top region.
More later.
Last edited by Bill Spight on Sat Sep 26, 2020 10:21 am, edited 2 times in total.
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.
-
Gérard TAILLE
- Gosei
- Posts: 1346
- Joined: Sun Aug 23, 2020 2:47 am
- Rank: 1d
- GD Posts: 0
- Has thanked: 21 times
- Been thanked: 57 times
Re: Thermography
Oops, I missed the ko you mentionned!
Let me have the opportunity to build a simpler position because this one does not reflect the issue I have in mind.
Let me have the opportunity to build a simpler position because this one does not reflect the issue I have in mind.
-
Bill Spight
- Honinbo
- Posts: 10905
- Joined: Wed Apr 21, 2010 1:24 pm
- Has thanked: 3651 times
- Been thanked: 3373 times
Re: Thermography
Let's make the traditional assumption of no ko threats. ThenGérard TAILLE wrote:In order to talk about thermograph let's me verify my understanding is correct:
Let's assume the best sequence for black is the sente following sequence:
and let's suppose the best sequence for white is the gote move:
Is the following thermograph correct with this assumption?
This White reverse sente will not appear in the original thermograph. The original count is -3 and the reverse sente gains 5.
The local score is -3.
In this case the original count is -4 and White's reverse sente gains 4. These values will hold with more dame.
The attached thermograph is like that, but the right wall is 1 pt. off.
And we still cannot assume that the b and c areas are independent.
More later.
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.
-
Gérard TAILLE
- Gosei
- Posts: 1346
- Joined: Sun Aug 23, 2020 2:47 am
- Rank: 1d
- GD Posts: 0
- Has thanked: 21 times
- Been thanked: 57 times
Re: Thermography
Bill, let me first verify with you if this new position fits my issue:
Diagramm 1
Black to play I hope the best sequence is the following
Diagramm 2
Black to play here I hope the best sequence is the following
If the above sequences are correct my basic question is the following:
Black to play Can thermography help (I do not claim for a solution given by thermography but just an help!) to choose between "a", "b" and "c" depending of the environment (here the presence or absence of point d) ?
BTW if the environment is empty you can see that the correct black move is the ogeima at "c".
Diagramm 1
Black to play I hope the best sequence is the following
Diagramm 2
Black to play here I hope the best sequence is the following
If the above sequences are correct my basic question is the following:
Black to play Can thermography help (I do not claim for a solution given by thermography but just an help!) to choose between "a", "b" and "c" depending of the environment (here the presence or absence of point d) ?
BTW if the environment is empty you can see that the correct black move is the ogeima at "c".
-
Bill Spight
- Honinbo
- Posts: 10905
- Joined: Wed Apr 21, 2010 1:24 pm
- Has thanked: 3651 times
- Been thanked: 3373 times
Re: Thermography
Basically, no.Gérard TAILLE wrote:Bill, let me first verify with you if this new position fits my issue:
Diagramm 1
Black to play I hope the best sequence is the following
Diagramm 2
Black to play here I hope the best sequence is the following
If the above sequences are correct my basic question is the following:
Black to play Can thermography help (I do not claim for a solution given by thermography but just an help!) to choose between "a", "b" and "c" depending of the environment (here the presence or absence of point d) ?
Why? Because thermography works best with a rich environment of numerous alternative plays that are close in size. Both of these environments are sparse with large temperature drops.
Still, thermography offers a preference of plays to try in order. However, with so few plays on the board, it is probably easier to work out best play than to derive the thermographs.
That said, thermography's top choice of plays works for the first board.
Result: Black +8, the same as with the sequence you found.
However, it is not as good for the second board.
The result is only +6, which is 1 point worse than the sequence you found.
However, because of the big temperature drop after F-01, you might derive the thermograph of the top region plus F-01, in which case that thermograph will indicate how to play at or below temperature 1. The combined thermograph will show that after Black takes sente she will then play at F-01, and then it will be better to leave White a sente at temperature 1 than a gote at temperature 2, even at the cost of 1 point on average. But of course you can come to that conclusion without figuring out the thermograph.
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.
-
Gérard TAILLE
- Gosei
- Posts: 1346
- Joined: Sun Aug 23, 2020 2:47 am
- Rank: 1d
- GD Posts: 0
- Has thanked: 21 times
- Been thanked: 57 times
Re: Thermography
Very interesting Bill. Now I begin to understand !Bill Spight wrote: Basically, no.
Why? Because thermography works best with a rich environment of numerous alternative plays that are close in size. Both of these environments are sparse with large temperature drops.
I tried to go further in order to answer the following question: under an "ideal" environment, can thermography help choosing between the gote ogeima and the sente keima?Bill Spight wrote: Still, thermography offers a preference of plays to try in order. However, with so few plays on the board, it is probably easier to work out best play than to derive the thermographs.
I tried to draw the corresponding combined thermograph (choosing to ignore the point of the white eye) and the answer seems yes but I am not completly sure:
Above temperature +3 you have to choose the sente keima and under this temperature you have to choose ogeima.
In addition, in order to avoid a reverse sente white move, you would be advised to play the sente keima before you reach the +4 temperature
Is that true ?
- Attachments
-
- keima vs ogeima.png (15.14 KiB) Viewed 118819 times
-
Gérard TAILLE
- Gosei
- Posts: 1346
- Joined: Sun Aug 23, 2020 2:47 am
- Rank: 1d
- GD Posts: 0
- Has thanked: 21 times
- Been thanked: 57 times
Re: Thermography
Yes Bill, after a deeper analysis I understand clearly what you mean. In fact I see some interesting similarity with double sente moves analysis.Bill Spight wrote:
Basically, no.
Why? Because thermography works best with a rich environment of numerous alternative plays that are close in size. Both of these environments are sparse with large temperature drops.
Still, thermography offers a preference of plays to try in order. However, with so few plays on the board, it is probably easier to work out best play than to derive the thermographs.
When thinking about what you call a rich environment of numerous alternative plays that are close in size it is clear that you cannot find in this ideal environment what is commonly called a double sente move.
If you cannot (or you do not want ?) read all the yose, you have to exclude from the environment all double sente moves and then you can assume the remaining environment is ideal.
Let'us take only one double sente area and assume white has just played in this area threatening a big got move g >> t. We are now in a very common situation where it exists a big gap between g and t.
Now it is black to play and, to avoid answering white threat and give her a good reverse sente move, black decides to play a sente move similar to move at "a" or "b" in the previous diagram. What move do you choose ? "a" or "b" ?
What is the difference between "a" and "b" ? They have the same miai value but "b" create a gote move with a miai value equal to +1.
As a consequence if t >= 1 the two moves "a" and "b" are equivalent.
What happens if 0 <= t < 1 ?
The key in this problem seems to be the tedomari/miai situation above t.
If black plays "a" in sente she has built a tedomari situation above t, made of only big gote move g
In the other hand if black plays "b" in sente she has built a miai situation above t, made of the big gote move g and the gote move of value +1 > t
As a consequence black must choose move "a".
Now let's take a situation with two double sente areas and assume black has taken the first one and white has answered with the second one. We have now two big gote moves g1 and g2 >> t. You can see that the tedomari/miai situation is the reverse comparing to the previous one.
As a consequence black must choose move "b".
It is exactly the situation I created in my problem with the temperature of the environment equal to zero and:
- in first diagram two gote moves => black must choose "b" to create a tedomari situation
- in second diagram only one gote move => black must choose "a" to avoid creating a miai situation.
Thank you again Bill for your help which allowed me to try to go farther (but maybe with some new mistakes ??)
-
Bill Spight
- Honinbo
- Posts: 10905
- Joined: Wed Apr 21, 2010 1:24 pm
- Has thanked: 3651 times
- Been thanked: 3373 times
Re: Thermography
Thermography does that by definition.Gérard TAILLE wrote:Very interesting Bill. Now I begin to understand !Bill Spight wrote: Basically, no.
Why? Because thermography works best with a rich environment of numerous alternative plays that are close in size. Both of these environments are sparse with large temperature drops.
I tried to go further in order to answer the following question: under an "ideal" environment, can thermography help choosing between the gote ogeima and the sente keima?Bill Spight wrote: Still, thermography offers a preference of plays to try in order. However, with so few plays on the board, it is probably easier to work out best play than to derive the thermographs.
However, the large monkey jump (ogeima) is sente, too.
I tried to draw the corresponding combined thermograph (choosing to ignore the point of the white eye) and the answer seems yes but I am not completly sure:
Above temperature +3 you have to choose the sente keima and under this temperature you have to choose ogeima.
In addition, in order to avoid a reverse sente white move, you would be advised to play the sente keima before you reach the +4 temperature
Is that true ?[/quote]
I don't know what you mean by ignoring the point of the White eye.
One option not shown yet is the kosumi.
We can compare it to the keima by means of a difference game. Let's mirror the board, except for the results of the two different sente exchanges.
If the kosumi exchange is at least as good as the keima exchange then White to play cannot win the difference game.
After
If
If
White to play cannot win the difference game, so the kosumi sente is at least as good as the keima sente.
But are the two equivalent? If so, then Black to play cannot win the difference game, either. Let' see.
Therefore, the kosumi sente is better than the keima sente.
(N. B. We cannot conclude that if both plays are gote.)
While we are at it, let's compare the kosumi sente to the crawl sente.
Black plays the hane-and-connect on the right and gets the last play on the left to win by 1 pt. If
If
If White plays the hane-and-connect on the right side, then Black plays sente on the left and gets the last play for jigo.
So the kosumi sente is better than the crawl sente, as well.
That's two down, one to go.
Last edited by Bill Spight on Sun Sep 27, 2020 11:47 am, edited 1 time in total.
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.
-
Bill Spight
- Honinbo
- Posts: 10905
- Joined: Wed Apr 21, 2010 1:24 pm
- Has thanked: 3651 times
- Been thanked: 3373 times
Re: Thermography
At your peril, OC.Gérard TAILLE wrote:Yes Bill, after a deeper analysis I understand clearly what you mean. In fact I see some interesting similarity with double sente moves analysis.Bill Spight wrote:
Basically, no.
Why? Because thermography works best with a rich environment of numerous alternative plays that are close in size. Both of these environments are sparse with large temperature drops.
Still, thermography offers a preference of plays to try in order. However, with so few plays on the board, it is probably easier to work out best play than to derive the thermographs.
When thinking about what you call a rich environment of numerous alternative plays that are close in size it is clear that you cannot find in this ideal environment what is commonly called a double sente move.
If you cannot (or you do not want ?) read all the yose, you have to exclude from the environment all double sente moves and then you can assume the remaining environment is ideal.
It was known in the 1970s that there is a problem with the idea of double sente. See Ogawa-Davies, for instance. OC, there are global double sente, but they depend upon what else is on the board. In terms of CGT evaluation or even traditional evaluation of go positions, they do not exist. Circa 1980 I submitted an article to Go World to that effect, but it was not accepted. {shrug} For more on double sente, see https://senseis.xmp.net/?DoubleSenteIsRelative .
Neither is as good as the kosumi.What is the difference between "a" and "b" ?
If you do a difference game to compare the two as sente, you find that neither is better than the other, but they are not equivalent.
Neither sente can be shown to be as good as the other. IOW, they are incomparable. Which is better, if either, depends on the rest of the board.
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.
-
Gérard TAILLE
- Gosei
- Posts: 1346
- Joined: Sun Aug 23, 2020 2:47 am
- Rank: 1d
- GD Posts: 0
- Has thanked: 21 times
- Been thanked: 57 times
Re: Thermography
After
Let me try this other move:
At first sight, because the exchange
I see two possible answers for black:
if black a: white can simply answer
if black b: white cut at
This is again clearly a loss for black because by playing the kosumi instead of the large jump black offers white not only this move