Dev Builds » 20260504-0632

Use this dev build

NCM plays each Stockfish dev build 20,000 times against Stockfish 15. This yields an approximate Elo difference and establishes confidence in the strength of the dev builds.

Summary

Host Duration Avg Base NPS Games WLD Standard Elo Ptnml(0-2) Gamepair Elo
ncm-dbt-01 06:38:04 583419 4000 1781 328 1891 +132.24 ± 4.48 0 32 513 1425 30 +309.29 ± 15.04
ncm-dbt-02 06:39:06 585667 4026 1794 344 1888 +131.01 ± 4.37 1 15 562 1403 32 +304.7 ± 14.3
ncm-dbt-03 06:39:48 584929 3996 1771 324 1901 +131.79 ± 4.55 0 31 527 1402 38 +304.9 ± 14.84
ncm-dbt-04 06:39:43 567118 3986 1747 340 1899 +128.15 ± 4.47 0 21 578 1360 34 +293.89 ± 14.1
ncm-dbt-05 06:39:31 581768 3992 1753 335 1904 +129.04 ± 4.51 0 29 553 1381 33 +297.2 ± 14.46
20000 8846 1671 9483 +130.44 ± 2.0 1 128 2733 6971 167 +301.94 ± 6.5

Test Detail

ID Host Base NPS Games WLD Standard Elo Ptnml(0-2) Gamepair Elo CLI PGN
467608 ncm-dbt-02 586266 26 13 3 10 +140.8 ± 64.93 0 0 4 8 1 +296.06 ± 224.51
467607 ncm-dbt-05 580323 492 212 43 237 +124.4 ± 13.22 0 3 77 160 6 +277.06 ± 38.91
467606 ncm-dbt-04 567561 486 208 39 239 +126.07 ± 12.71 0 2 74 163 4 +287.43 ± 39.65
467605 ncm-dbt-03 585928 496 205 36 255 +123.31 ± 13.17 0 8 64 175 1 +286.4 ± 43.03
467604 ncm-dbt-01 584076 500 227 43 230 +134.15 ± 11.86 0 1 67 179 3 +318.25 ± 41.77
467603 ncm-dbt-02 585084 500 226 38 236 +137.37 ± 12.36 0 1 66 177 6 +321.19 ± 42.12
467602 ncm-dbt-05 579620 500 233 39 228 +142.25 ± 11.51 0 2 54 192 2 +352.8 ± 47.05
467601 ncm-dbt-04 568673 500 225 39 236 +135.76 ± 13.01 0 2 68 172 8 +309.64 ± 41.56
467600 ncm-dbt-03 585211 500 215 44 241 +123.81 ± 12.73 0 3 77 166 4 +280.42 ± 38.93
467599 ncm-dbt-01 585211 500 220 45 235 +126.97 ± 13.76 0 10 58 179 3 +293.29 ± 44.99
467598 ncm-dbt-02 586943 500 223 48 229 +126.97 ± 12.28 0 2 74 171 3 +293.29 ± 39.69
467597 ncm-dbt-05 578259 500 224 52 224 +124.6 ± 13.09 0 4 75 166 5 +280.42 ± 39.57
467596 ncm-dbt-04 566849 500 219 48 233 +123.81 ± 12.92 0 4 75 167 4 +280.42 ± 39.57
467595 ncm-dbt-01 583824 500 222 39 239 +133.34 ± 12.29 0 3 64 180 3 +315.35 ± 43.03
467594 ncm-dbt-03 585759 500 220 35 245 +134.95 ± 12.64 0 4 61 181 4 +318.25 ± 44.18
467593 ncm-dbt-02 585169 500 227 43 230 +134.15 ± 12.47 0 1 70 173 6 +309.64 ± 40.79
467592 ncm-dbt-05 583740 500 212 38 250 +126.17 ± 14.12 0 10 61 174 5 +285.49 ± 43.92
467591 ncm-dbt-04 568236 500 223 45 232 +129.35 ± 13.36 0 4 71 168 7 +290.66 ± 40.76
467590 ncm-dbt-01 582819 500 218 34 248 +134.15 ± 11.64 0 2 63 184 1 +324.17 ± 43.32
467589 ncm-dbt-03 586223 500 233 41 226 +140.62 ± 12.02 0 0 64 180 6 +333.32 ± 42.66
467588 ncm-dbt-02 585674 500 214 35 251 +130.14 ± 11.99 0 0 75 171 4 +301.33 ± 39.1
467587 ncm-dbt-04 566888 500 221 41 238 +130.94 ± 12.17 0 3 66 179 2 +309.64 ± 42.33
467586 ncm-dbt-05 578588 500 226 43 231 +133.34 ± 13.08 0 3 68 172 7 +304.07 ± 41.65
467585 ncm-dbt-01 583531 500 218 36 246 +132.54 ± 13.28 0 5 64 175 6 +304.07 ± 43.1
467584 ncm-dbt-03 583908 500 224 43 233 +131.74 ± 13.49 0 3 72 166 9 +293.29 ± 40.39
467583 ncm-dbt-02 582945 500 221 42 237 +130.14 ± 12.59 0 5 63 180 2 +306.84 ± 43.45
467582 ncm-dbt-04 564605 500 224 52 224 +124.6 ± 12.14 0 2 76 170 2 +288.06 ± 39.11
467581 ncm-dbt-05 580199 500 212 45 243 +120.67 ± 12.41 0 3 79 166 2 +275.45 ± 38.39
467580 ncm-dbt-03 582068 500 225 45 230 +130.94 ± 12.76 0 3 69 173 5 +301.33 ± 41.33
467579 ncm-dbt-01 579785 500 227 44 229 +133.34 ± 12.29 0 2 67 177 4 +312.48 ± 41.9
467578 ncm-dbt-02 585928 500 227 38 235 +138.18 ± 12.12 0 1 64 180 5 +327.18 ± 42.83
467577 ncm-dbt-04 567086 500 210 45 245 +119.11 ± 12.99 0 3 84 158 5 +263.42 ± 37.11
467576 ncm-dbt-05 580655 500 222 34 244 +137.37 ± 12.36 0 3 60 183 4 +327.18 ± 44.54
467575 ncm-dbt-01 584076 500 224 41 235 +133.34 ± 13.26 0 6 60 179 5 +309.64 ± 44.55
467574 ncm-dbt-03 585674 500 223 38 239 +134.95 ± 12.64 0 3 64 178 5 +315.35 ± 43.03
467573 ncm-dbt-02 585843 500 215 49 236 +119.89 ± 12.79 0 4 79 164 3 +270.57 ± 38.47
467572 ncm-dbt-01 584034 500 225 46 229 +130.14 ± 12.78 0 3 70 172 5 +298.62 ± 41.01
467571 ncm-dbt-05 592763 500 212 41 247 +123.81 ± 11.96 0 1 79 168 2 +285.49 ± 38.15
467570 ncm-dbt-04 567047 500 217 31 252 +135.76 ± 11.58 0 1 64 183 2 +327.18 ± 42.83
467569 ncm-dbt-02 587155 500 228 48 224 +130.94 ± 12.37 1 1 67 179 2 +312.48 ± 41.9
467568 ncm-dbt-03 584664 500 226 42 232 +134.15 ± 13.24 0 7 56 183 4 +315.35 ± 46.07

Commit

Commit ID dc1686345cf29789cdb823441bf198928a5f0d66
Author anematode
Date 2026-05-04 06:32:23 UTC
Hyperbola quintessence for ARM Passed STC https://tests.stockfishchess.org/tests/view/69f44c1e1e5788938e86aa2a LLR: 2.93 (-2.94,2.94) <0.00,2.00> Total: 27680 W: 7340 L: 7053 D: 13287 Ptnml(0-2): 72, 2862, 7683, 3153, 70 x86 is unaffected Data from Joost's machine (Neoverse V2): ``` ==== master ==== ==== Bench: 2723949 ==== 1 Nodes/second : 276819933 2 Nodes/second : 273971948 3 Nodes/second : 275567995 Average (over 3): 275453292 ==== 5b54755db23a3de29407b805b85e7bbdef28df49 ==== ==== Bench: 2723949 ==== 1 Nodes/second : 282861542 2 Nodes/second : 279085277 3 Nodes/second : 279612223 Average (over 3): 280519680 (+1.8%) ``` Data from my M1 macbook ``` Result of 100 runs ================== base (./stockfish ) = 1474702 +/- 6169 test (...fish.rbit-pr) = 1500236 +/- 6690 diff = +25533 +/- 4011 speedup = +0.0173 P(speedup > 0) = 1.0000 ``` Hyperbola quintessence works nicely on ARM because it has an efficient bit reversal instruction `rbit`. This lets us avoid the large magic bitboards lookup table. Codegen looks nice (this is for rook attacks I think): ``` 0000000100001ecc <__ZN9Stockfish10attacks_bbILNS_9PieceTypeE3EEEyNS_6SquareEy>: 100001ecc: 2a0003e8 mov w8, w0 100001ed0: f002cb09 adrp x9, 0x105964000 <dyld_stub_binder+0x105964000> 100001ed4: 91200129 add x9, x9, #0x800 100001ed8: 8b081928 add x8, x9, x8, lsl #6 100001edc: a9402909 ldp x9, x10, [x8] 100001ee0: 8a01012b and x11, x9, x1 100001ee4: dac0016c rbit x12, x11 100001ee8: a941210d ldp x13, x8, [x8, #0x10] 100001eec: cb08018c sub x12, x12, x8 100001ef0: dac0018c rbit x12, x12 100001ef4: cb0d016b sub x11, x11, x13 100001ef8: ca0b018b eor x11, x12, x11 100001efc: 8a090169 and x9, x11, x9 100001f00: 8a01014b and x11, x10, x1 100001f04: dac0016c rbit x12, x11 100001f08: cb080188 sub x8, x12, x8 100001f0c: dac00108 rbit x8, x8 100001f10: cb0d016b sub x11, x11, x13 100001f14: ca0b0108 eor x8, x8, x11 100001f18: 8a0a0108 and x8, x8, x10 100001f1c: 8b090100 add x0, x8, x9 100001f20: d65f03c0 ret ``` closes https://github.com/official-stockfish/Stockfish/pull/6795 No functional change
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