Don't score as an immediate draw 2-fold repetitions of the root position (fixes #948) #1126
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mcostalba
reviewed
May 27, 2017
src/position.cpp
Outdated
| @@ -1103,7 +1103,7 @@ bool Position::is_draw(int ply) const { | |||
| // repeats once earlier but after or at the root, or repeats twice | |||
| // strictly before the root. | |||
In the current version a search stops when the current position is the same as any position earlier in the search stack, including the root position but excluding positions before the root. The new version makes an exception for repeating the root position. This gives correct scores for moves in the MultiPV > 1 mode. Fixes official-stockfish#948 (see it for the detailed description of the bug). LTC: http://tests.stockfishchess.org/tests/view/587910bc0ebc5915193f754b ELO: 0.38 +-1.7 (95%) LOS: 66.8% Total: 40000 W: 5166 L: 5122 D: 29712 STC: http://tests.stockfishchess.org/tests/view/5922e6230ebc59035df34a50 LLR: 2.94 (-2.94,2.94) [-3.00,1.00] Total: 94622 W: 17059 L: 17064 D: 60499 LTC: http://tests.stockfishchess.org/tests/view/59273a000ebc59035df34c03 LLR: 2.96 (-2.94,2.94) [-3.00,1.00] Total: 61259 W: 7965 L: 7897 D: 45397 Bench: 6599721
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OK, I've updated the comment. |
SapphireBrand
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Jun 7, 2017
In the current version a search stops when the current position is the same as any position earlier in the search stack, including the root position but excluding positions before the root. The new version makes an exception for repeating the root position. This gives correct scores for moves in the MultiPV > 1 mode. Fixes official-stockfish#948 (see it for the detailed description of the bug). LTC: http://tests.stockfishchess.org/tests/view/587910bc0ebc5915193f754b ELO: 0.38 +-1.7 (95%) LOS: 66.8% Total: 40000 W: 5166 L: 5122 D: 29712 STC: http://tests.stockfishchess.org/tests/view/5922e6230ebc59035df34a50 LLR: 2.94 (-2.94,2.94) [-3.00,1.00] Total: 94622 W: 17059 L: 17064 D: 60499 LTC: http://tests.stockfishchess.org/tests/view/59273a000ebc59035df34c03 LLR: 2.96 (-2.94,2.94) [-3.00,1.00] Total: 61259 W: 7965 L: 7897 D: 45397 Bench: 6599721 Closes official-stockfish#1126
SapphireBrand
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Jun 8, 2017
In the current version a search stops when the current position is the same as any position earlier in the search stack, including the root position but excluding positions before the root. The new version makes an exception for repeating the root position. This gives correct scores for moves in the MultiPV > 1 mode. Fixes official-stockfish#948 (see it for the detailed description of the bug). LTC: http://tests.stockfishchess.org/tests/view/587910bc0ebc5915193f754b ELO: 0.38 +-1.7 (95%) LOS: 66.8% Total: 40000 W: 5166 L: 5122 D: 29712 STC: http://tests.stockfishchess.org/tests/view/5922e6230ebc59035df34a50 LLR: 2.94 (-2.94,2.94) [-3.00,1.00] Total: 94622 W: 17059 L: 17064 D: 60499 LTC: http://tests.stockfishchess.org/tests/view/59273a000ebc59035df34c03 LLR: 2.96 (-2.94,2.94) [-3.00,1.00] Total: 61259 W: 7965 L: 7897 D: 45397 Bench: 6599721 Closes official-stockfish#1126
SapphireBrand
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Jun 9, 2017
In the current version a search stops when the current position is the same as any position earlier in the search stack, including the root position but excluding positions before the root. The new version makes an exception for repeating the root position. This gives correct scores for moves in the MultiPV > 1 mode. Fixes official-stockfish#948 (see it for the detailed description of the bug). LTC: http://tests.stockfishchess.org/tests/view/587910bc0ebc5915193f754b ELO: 0.38 +-1.7 (95%) LOS: 66.8% Total: 40000 W: 5166 L: 5122 D: 29712 STC: http://tests.stockfishchess.org/tests/view/5922e6230ebc59035df34a50 LLR: 2.94 (-2.94,2.94) [-3.00,1.00] Total: 94622 W: 17059 L: 17064 D: 60499 LTC: http://tests.stockfishchess.org/tests/view/59273a000ebc59035df34c03 LLR: 2.96 (-2.94,2.94) [-3.00,1.00] Total: 61259 W: 7965 L: 7897 D: 45397 Bench: 6599721 Closes official-stockfish#1126
atumanian
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Jan 24, 2018
In the current version a search stops when the current position is the same as any position earlier in the search stack, including the root position but excluding positions before the root. The new version makes an exception for repeating the root position. This gives correct scores for moves in the MultiPV > 1 mode. Fixes official-stockfish#948 (see it for the detailed description of the bug). LTC: http://tests.stockfishchess.org/tests/view/587910bc0ebc5915193f754b ELO: 0.38 +-1.7 (95%) LOS: 66.8% Total: 40000 W: 5166 L: 5122 D: 29712 STC: http://tests.stockfishchess.org/tests/view/5922e6230ebc59035df34a50 LLR: 2.94 (-2.94,2.94) [-3.00,1.00] Total: 94622 W: 17059 L: 17064 D: 60499 LTC: http://tests.stockfishchess.org/tests/view/59273a000ebc59035df34c03 LLR: 2.96 (-2.94,2.94) [-3.00,1.00] Total: 61259 W: 7965 L: 7897 D: 45397 Bench: 6599721 Closes official-stockfish#1126
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In the current version a search stops when the current position is the same as any position earlier in the search stack, including the root position but excluding positions before the root. The new version makes an exception for repeating the root position.
This gives correct scores for moves in the MultiPV > 1 mode.
Fixes #948 (see it for the detailed description of the bug).
Idea by @saproj (see the original PR - #925)
LTC: http://tests.stockfishchess.org/tests/view/587910bc0ebc5915193f754b
ELO: 0.38 +-1.7 (95%) LOS: 66.8%
Total: 40000 W: 5166 L: 5122 D: 29712
STC: http://tests.stockfishchess.org/tests/view/5922e6230ebc59035df34a50
LLR: 2.94 (-2.94,2.94) [-3.00,1.00]
Total: 94622 W: 17059 L: 17064 D: 60499
LTC: http://tests.stockfishchess.org/tests/view/59273a000ebc59035df34c03
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 61259 W: 7965 L: 7897 D: 45397
Bench: 6599721