Chessbase engines (fritz, shredder, junior, etc.) often will show a #150 (or other high numbers near that) as their positional evaluation. It's obvious that it doesn't really mean that there's a mate in 150 as it's not looking that deep. So it must stand for something, but I'm not sure what. It's only displayed when one side has a easily winning advantage. Does anyone know what it means? Does it have something to do with tablebases?
Originally posted by ark13Is it because a computer cannot represent infinity (i.e a win) so it just selects a large number much greater than the combined value of the pieces?
Chessbase engines (fritz, shredder, junior, etc.) often will show a #150 (or other high numbers near that) as their positional evaluation. It's obvious that it doesn't really mean that there's a mate in 150 as it's not looking that deep. So it must stand for something, but I'm not sure what. It's only displayed when one side has a easily winning advantage. Does anyone know what it means? Does it have something to do with tablebases?
Originally posted by John DalmasNo, I don't think that's it. Because it doesn't say the advantage is 150, or something like that. Instead, it says mate in 150.
Is it because a computer cannot represent infinity (i.e a win) so it just selects a large number much greater than the combined value of the pieces?
Originally posted by ark13I think that John Dalmas is on the right lines, it says #150 to indicate a large advantage that can't be calculated, so mate in infinity. As an aside Integer infinity can't be represented, but the ISO floating point representation allows for it (all bits zero or something like that, except for the first bit that shows the sign so + and - infinity are distinct).
No, I don't think that's it. Because it doesn't say the advantage is 150, or something like that. Instead, it says mate in 150.
Originally posted by DeepThoughtBut how could the advantage be so large it can't be calculated? It has as many numbers as it needs for normal positions. There can't be an infinite advantage without it being mate. And once it sees mate, then it can't express it with numbers. But clearly it doesn't see mate when it shows mate in 150, or else it would have it in a reasonable number.
I think that John Dalmas is on the right lines, it says #150 to indicate a large advantage that can't be calculated, so mate in infinity. As an aside Integer infinity can't be represented, but the ISO floating point representation allows for it (all bits zero or something like that, except for the first bit that shows the sign so + and - infinity are distinct).
Originally posted by ark13Mine never does this. If it can't see a forced mate it displays a number. That number is the number of pawns it believes a side is ahead by. Positive means white is ahead, negative means black is ahead.
Chessbase engines (fritz, shredder, junior, etc.) often will show a #150 (or other high numbers near that) as their positional evaluation. It's obvious that it doesn't really mean that there's a mate in 150 as it's not looking that deep. So it must stand for something, but I'm not sure what. It's only displayed when one side has a easily winning advantage. Does anyone know what it means? Does it have something to do with tablebases?
In some positions it gets to around 22. However whenever it displays a #number it means mate in that many. If the ending involves tablebases engines can find mates extending many many moves. Say fritz looks at a position and finds that in 7 moves it can force a trade. The position after the trade is one in the tablebases you have attached to it. It will then know exactly how many moves to mate from there instantly, even if it is 100 or more.
Originally posted by XanthosNZMy experience is as XanthosNZ.
Mine never does this. If it can't see a forced mate it displays a number. That number is the number of pawns it believes a side is ahead by. Positive means white is ahead, negative means black is ahead.
I've seen mate in 23 or more often since installing the five piece TBs.
Originally posted by XanthosNZYeah, I know what you're saying. And mine usually does exactly what you're saying. However, sometimes, it'll display something like #150, or #149, or #175, etc. I have no idea why, but all of my engines do that.
Mine never does this. If it can't see a forced mate it displays a number. That number is the number of pawns it believes a side is ahead by. Positive means white is ahead, negative means black is ahead.
In some positions it gets to around 22. However whenever it displays a #number it means mate in that many. If the ending involves tablebases engines ca ...[text shortened]... t will then know exactly how many moves to mate from there instantly, even if it is 100 or more.
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Originally posted by XanthosNZAfter black's 33rd move here, Shredder finds Rc7 and shows (#150). After a few minutes of analysis, it'll eventually change the evaluation to (#6).
Give me a position where it displays something like that.
This also strikes me as strange. The engine is getting 14, 15, and 16 ply deep, and fails to find a forced mate in 6 full moves right away. It should find it after 12.
Originally posted by ark13Where?
After black's 33rd move here, Shredder finds Rc7 and shows (#150). After a few minutes of analysis, it'll eventually change the evaluation to (#6).
This also strikes me as strange. The engine is getting 14, 15, and 16 ply deep, and fails to find a forced mate in 6 full moves right away. It should find it after 12.
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Originally posted by XanthosNZEDIT: Oh, I just realized I didn't post the game😛😳
Where?
Game 624881
Originally posted by ark13Interesting. I ran Hiarcs 9, Fritz 8, and Crafty 19.19 on that position. Crafty and Hiarcs both showed #7 after 4 seconds at a depth of 9 plies; Fritz showed #7 by the time it finished opening, and showed a depth of 6 plies. Hiarcs hit 12 plies at 51 seconds. I didn't run the others that long. Rc7 is the move, of course.
After black's 33rd move here, Shredder finds Rc7 and shows (#150). After a few minutes of analysis, it'll eventually change the evaluation to (#6).
This also strikes me as strange. The engine is getting 14, 15, and 16 ply deep, and fails to find a forced mate in 6 full moves right away. It should find it after 12.
I'd like to see the line that produces #6.
Perhaps processor speed and RAM is a factor. I'm running a P-4 550 3.4 GhZ processor with 512 RAM. The engines are set at 128 MB hash.
Sorry I don't have Shredder; it's on my wish list, but I may get CB 9 first.
Originally posted by WulebgrMaybe it's just something weird with Shredder. I can't remember if I've seen my other engines doing it. Fritz found it quickly, without the mate in 150. However, my Fritz is behaving strangely too in that on white's move, he shows Rc7 with mate in 8. Then, after Rc7, he shows mate in 6. But when I go back, it says mate in 8 again😕
Interesting. I ran Hiarcs 9, Fritz 8, and Crafty 19.19 on that position. Crafty and Hiarcs both showed #7 after 4 seconds at a depth of 9 plies; Fritz showed #7 by the time it finished opening, and showed a depth of 6 plies. Hiarcs hit 12 plies at 51 seconds. I didn't run the others that long. Rc7 is the move, of course.
I'd like to see the line that pr ...[text shortened]... t 128 MB hash.
Sorry I don't have Shredder; it's on my wish list, but I may get CB 9 first.
Oh, and Shredder only sees mate in 7 before Rc7. It was mate in 6 after.
Originally posted by ark13Never seen that... and I usually analyze all my losses.
Chessbase engines (fritz, shredder, junior, etc.) often will show a #150 (or other high numbers near that) as their positional evaluation. It's obvious that it doesn't really mean that there's a mate in 150 as it's not looking that deep. So it must stand for something, but I'm not sure what. It's only displayed when one side has a easily winning advantage. Does anyone know what it means? Does it have something to do with tablebases?