🔍 Add Internal Iterative Reduction (IIR)

[eduherminio]

Most basic attempt, without min. depth 👎🏽 (it also makes a bunch of tests fail, but because they assume a certain depth to be reached when searching depth 5)

Score of Lynx-iir-basic-1965-win-x64 vs Lynx 1964 - main: 764 - 840 - 1036  [0.486] 2640
...      Lynx-iir-basic-1965-win-x64 playing White: 516 - 297 - 507  [0.583] 1320
...      Lynx-iir-basic-1965-win-x64 playing Black: 248 - 543 - 529  [0.388] 1320
...      White vs Black: 1059 - 545 - 1036  [0.597] 2640
Elo difference: -10.0 +/- 10.3, LOS: 2.9 %, DrawRatio: 39.2 %
SPRT: llr -2.25 (-77.9%), lbound -2.25, ubound 2.89 - H0 was accepted

Using min depth 4, as recommended in EP discord

8+0.08 👍🏽ish (had to cancel)

Score of Lynx-iir-basic-1966-win-x64 vs Lynx 1964 - main: 3972 - 3794 - 4844  [0.507] 12610
...      Lynx-iir-basic-1966-win-x64 playing White: 2699 - 1235 - 2372  [0.616] 6306
...      Lynx-iir-basic-1966-win-x64 playing Black: 1273 - 2559 - 2472  [0.398] 6304
...      White vs Black: 5258 - 2508 - 4844  [0.609] 12610
Elo difference: 4.9 +/- 4.8, LOS: 97.8 %, DrawRatio: 38.4 %
SPRT: llr 2.04 (70.6%), lbound -2.25, ubound 2.89

40+0.4 👍🏽

Score of Lynx-iir-basic-1966-win-x64 vs Lynx 1964 - main: 1628 - 1476 - 2472  [0.514] 5576
...      Lynx-iir-basic-1966-win-x64 playing White: 1170 - 404 - 1214  [0.637] 2788
...      Lynx-iir-basic-1966-win-x64 playing Black: 458 - 1072 - 1258  [0.390] 2788
...      White vs Black: 2242 - 862 - 2472  [0.624] 5576
Elo difference: 9.5 +/- 6.8, LOS: 99.7 %, DrawRatio: 44.3 %
SPRT: llr 2.89 (100.1%), lbound -2.25, ubound 2.89 - H1 was accepted

Try checking ttBestMove instead of ttHit failed as well

Using min depth 3 vs depth 4
8+0.08 👎🏽ish

Finished game 10401 (Lynx-iir-basic-1986-win-x64 vs Lynx-iir-basic-1985-win-x64): * {No result}
Score of Lynx-iir-basic-1986-win-x64 vs Lynx-iir-basic-1985-win-x64: 3154 - 3107 - 4137  [0.502] 10398
...      Lynx-iir-basic-1986-win-x64 playing White: 2146 - 998 - 2055  [0.610] 5199
...      Lynx-iir-basic-1986-win-x64 playing Black: 1008 - 2109 - 2082  [0.394] 5199
...      White vs Black: 4255 - 2006 - 4137  [0.608] 10398
Elo difference: 1.6 +/- 5.2, LOS: 72.4 %, DrawRatio: 39.8 %

Using min depth 5 vs depth 4
8+0.08 👎🏽ish

Score of Lynx-iir-basic-1987-win-x64 vs Lynx-iir-basic-1985-win-x64: 3194 - 3182 - 4054  [0.501] 10430
...      Lynx-iir-basic-1987-win-x64 playing White: 2166 - 1010 - 2040  [0.611] 5216
...      Lynx-iir-basic-1987-win-x64 playing Black: 1028 - 2172 - 2014  [0.390] 5214
...      White vs Black: 4338 - 2038 - 4054  [0.610] 10430
Elo difference: 0.4 +/- 5.2, LOS: 56.0 %, DrawRatio: 38.9 %
SPRT: llr -1.48 (-51.4%), lbound -2.25, ubound 2.89