Semeai improvements

[gunnar]

This ticket is intended for collecting and evaluating patches to improve the semeai reading, in particular with regard to the STS-RV test collection (see #41). It will be closed when no further short term improvements are in sight.

[gunnar]

Don't amalgamate dragons over three liberty strings. (Cf. #197)

[gunnar]

Don't allow sacrifice of goal worm when catching lunch in owl/semeai reading.

[gunnar]

There is no breakage on the standard regressions for gunnar_7_12.7 and a small increase in reading nodes (+0.089% +0.21% -0.041%). On STS-RV the result is five passes and no fails. The passes are

STS-RV_1:23     PASS 1 0 C3 [1 0 (C3|C2)]
STS-RV_GSAT:26  PASS 1 1 G2 [1 1 (E3|G2|F1)]
STS-RV_Misc:16  PASS 1 1 A18 [1 1 (B19|C19|A18)]
STS-RV_Misc:19  PASS 1 1 Q5 [1 1 (T5|S5|R5|Q5|O1)]
STS-RV_RH:18    PASS 0 0 PASS [0 0 PASS]

All these results are relative r2410.

[gunnar]

Don't amalgamate dragons over two liberty strings (probably not a good idea).

[gunnar]

Don't play outer liberties in recognized eyespace.

[gunnar]

Do some more distrusting of tactical moves in semeai reading.

[gunnar]

There's a rather bad breakage for gunnar_7_12.8 on the normal regressions:

owl:123         PASS 1 C5 [1 C5]
trevorb:590     PASS M9 [H12|M9]
semeai:73       FAIL 1 1 PASS [1 0 PASS]
semeai:74       FAIL 0 0 PASS [1 0 (PASS|L13)]
semeai:75       FAIL 1 1 PASS [1 0 PASS]
semeai:76       FAIL 0 0 PASS [1 0 (PASS|N3|K2)]
semeai:77       FAIL 1 1 PASS [1 0 PASS]
semeai:78       FAIL 0 0 PASS [1 0 (PASS|A6|C6|C1)]
semeai:79       FAIL 1 1 PASS [1 0 PASS]
semeai:80       FAIL 0 0 PASS [1 0 (PASS|E9|E8|J9|H5)]
owl1:279        PASS 1 PASS [1 PASS]
century2002:180 FAIL O11 [T9]
auto_handtalk:3 FAIL 1 T15 [2 T15]
gunnar:101      PASS T8 [T8]
thrash:23       FAIL J6 [A5|D7]
13x13b:21       FAIL J13 [K11]
seki:1106       FAIL C9 [C1]
seki:2050       FAIL dead [alive]
4 PASS
14 FAIL
Total nodes: 1704626871 3334488 12416594 (+0.1% -0.03% +0.02%)

For STS-RV it's rather the opposite, 14 passes, 2 fails:

STS-RV_1:3      PASS 1 1 D8 [1 1 (D8|C3|B3|A3)]
STS-RV_1:5      PASS 1 1 M4 [1 1 (M4|N4|R3|R2|R1)]
STS-RV_1:20     PASS 1 1 T3 [1 1 (R3|S4|S2|T3)]
STS-RV_1:54     PASS 1 0 O2 [1 0 (O2|O1|R2|Q1|S1)]
STS-RV_1:59     PASS 0 0 PASS [0 0 PASS]
STS-RV_1:158    PASS 1 1 P6 [1 1 (N3|O5|P6|Q6|R6|S6|T6)]
STS-RV_1:160    FAIL 0 0 PASS [1 1 (N17|017|O16|O15|O14|R13|T12)]
STS-RV_1:205    PASS 1 1 C2 [1 1 C2]
STS-RV_Misc:4   PASS 1 1 A10 [1 1 A10]
STS-RV_Misc:9   PASS 1 1 J1 [1 1 J1]
STS-RV_Misc:14  PASS 1 0 B9 [1 0 B9]
STS-RV_Misc:35  PASS 1 1 J1 [1 1 J1]
STS-RV_Misc:42  PASS 1 0 A9 [1 0 A9]
STS-RV_Misc:44  PASS 1 0 B9 [1 0 B9]
STS-RV_RH:67    FAIL 0 0 PASS [1 1 B4]
STS-RV_e:2      PASS 1 1 B17 [1 1 B17]

[gunnar]

Don't amalgamate dragons over three liberty strings or a specific class of two liberty strings.

[gunnar]

Replying to gunnar:

There is no breakage on the standard regressions for gunnar_7_12.7 and a small increase in reading nodes (+0.089% +0.21% -0.041%). On STS-RV the result is five passes and no fails.

The patch gunnar_7_12.7b has a mixed breakage with 6 passes and 5 fails on the normal regressions plus increasing the owl nodes by 0.7%. On STS-RV it adds one more pass for STS-RV_1:58.

The more complicated patch gunnar_7_12.7c retains the pass for STS-RV_1:58 but without any breakage on the normal regressions and the same node cost as gunnar_7_12.7.

[gunnar]

Replying to gunnar:

There's a rather bad breakage for gunnar_7_12.8 on the normal regressions:

The typical problem can be examplified with semeai:73. In this position

the patch changes the three white stones from a lunch to an eyespace. As a consequence black is found to have two eyes and claims life, whereas white doesn't look alive, so the semeai is statically evaluated as a full win for black.

[gunnar]

Revised patch

[gunnar]

semeai:133      FAIL 1 1 H2 [1 2 H2]

This is actually backwards. The correct result is 1 1 H2!.

[gunnar]

nngs2:150       FAIL J18 [M3|L3]

The semeai reading for the upper left corner is nowhere near correct with or without the patch gunnar_7_12.9.

[gunnar]

gunnar_7_12.8b makes a huge difference when it comes to avoiding to play supposedly lunch-capturing moves inside own eyespace, e.g. in STS-RV_e:2. That combined with a positive overall regression balance suffices for accepting it.

[gunnar]

Semeai testcase revisions.

[gunnar]

Avoid overvaluation of eyespaces which are split by a single stone in atari, plus tuning.