A tuning patch which cover the following changes:
increase the importance of queen and rook mobility in endgame and
decrease it in mg, since if we use the heavy pieces too early in the game
we will just make opponent develop their pieces by threatening ours.
King Psqt:
1)King will be encouraged more to stay in the first ranks in the MG
2)and will be encouraged more to go to the middle of the board/last ranks in the EG
Bishop scale better in EG
Logical changes on various psqt tables
1/6 of the changes of the last tuning session on mobility tables
STC: LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 227879 W: 41240 L: 40313 D: 146326
LTC : LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 167047 W: 21871 L: 21291 D: 123885
Bench: 5695960
Closes#1008
Fixes failing build for
make ARCH=x86-32 clean && make ARCH=x86-32 optimize=no build
by passing -m32 also to the link step.
Extend travis testing accordingly.
No functional change.
Closes#999
Minor non-functional simplifications in computing the scale factor.
In my opinion, the code is now slightly more readable:
- remove one condition which can never be satisfied.
- immediately return instead of assigning the sf variable.
Tested for non-regression:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 62162 W: 11166 L: 11115 D: 39881
No functional change
Closes#992
Also the penalty/bonus function is misleading, we
should simply change it to stat_bonus(depth) for
bonus and -stat_bonus(depth+ ONE_PLY) for extra
penalty.
STC:
LLR: 2.96 (-2.94,2.94) [0.00,5.00]
Total: 11656 W: 2183 L: 2008 D: 7465
LTC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 11152 W: 1531 L: 1377 D: 8244
Bench: 6101931
Results for 20 tests for each version (pgo-builds):
Base Test Diff
Mean 2110519 2118116 -7597
StDev 8727 4906 10112
p-value: 0,774
speedup: 0,004
Further verified for no regression:
http://tests.stockfishchess.org/tests/view/5885abd10ebc5915193f79e6
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 21786 W: 3959 L: 3840 D: 13987
No functional change
Move more code into eval_init, removing some
clutter in the main routine.
Write eval_init only from "our" point of view
(do not init the attackedBy[Them] bitboards).
Add mobilityArea to the evalinfo
A few edits while being there
tested for non-regression at STC
http://tests.stockfishchess.org/tests/view/587fab230ebc5915193f77d9
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 39585 W: 7183 L: 7094 D: 25308
Non functional change.
After we have taken into account all cheap evaluation
terms, we check whether the score exceeds a given threshold.
If this is the case, we return a scaled down evaluation.
STC:
LLR: 3.35 (-2.94,2.94) [0.00,5.00]
Total: 12575 W: 2316 L: 2122 D: 8137
LTC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 67480 W: 9016 L: 8677 D: 49787
Current version is the one rewritten by ceebo
further edited by me.
Bench: 5367704
After the history simplifications, we are only using Value Stats for CounterMoveHistory table. Therefore the parameter CM is not necessary.
No functional change.
Add asserts to check for overflow in Score * int multiplication.
There is no overflow in current master, but it would be easy to
create one as the scale of the current eval does not leave many
spare bits. For instance, adding the following unused variables
in master at the end of evaluate() (line 882 of evaluate.cpp)
overflows:
Score s1 = score * 4; // no overflow
Score s2 = score * 5; // overflow
Assertion failed: (eg_value(result) == (i * eg_value(s))),
function operator*, file ./types.h, line 336.
Same md5 checksum as current master for non debug compiles.
No functional change.
Order the enum and the array the same way they appear around line 250.
Makes it much easier to follow.
Add comments in the array definition and critical rows.
Use same terminology as elsewhere in pawns.cpp
No functional change.
Previously, we had duplicated History:
- one with (piece,to) called History
- one with (from,to) called FromTo
Now that we have only one, rename it to History, which is the generally accepted
name in the chess programming litterature for this technique.
Also correct some comments that had not been updated since the introduction of CMH.
No functional change.
Perform more complex verification and validation.
- signature.sh : extract and optionally compare Bench/Signature/Node count.
- perft.sh : verify perft counts for a number of positions.
- instrumented.sh : run a few commands or uci sequences through valgrind/sanitizer instrumented binaries.
- reprosearch.sh : verify reproducibility of search.
These script can be used from directly from the command line in the src directory.
Update travis script to use these shell scripts.
No functional change.
Now taht we correctly value-initialize Thread objects,
we don't need c'tors anymore because tables will be
zero-initialized by the compier when Thread object
is instanced.
Verified that we have no errors with Valgrind.
No functional change.
If not explicitly initialized in a class constructor,
then all data members are default-initialized when
the corresponing struct/class is instanced.
For array and built-in types (int, char, etc..)
default-initialization is a no-op and we need to
explicitly zero them.
No functional change.
Tested using syzygy bench method:
- 2016 random positions ranging between 3 and 10 pieces
- each searched using bench at depth=10
Same node count (and no speed regression).
No functional change.
EasyMove is cleared after every iteration of the
search if the 3rd move in the PV of the main thread
changes from the previous iteration. Therefore,
clearing EasyMove during a search iteration may be
excessive. The tests show that this is indeed unnecessary.
In the new version the EasyMove variable is used only in
the Thread::search function.
STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 47719 W: 8438 L: 8362 D: 30919
LTC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 122841 W: 15448 L: 15457 D: 91936
bench: 5468995
Implement a threefold repetition detection. Below are the examples of
problems fixed by this change.
Loosing move in a drawn position.
position fen 8/k7/3p4/p2P1p2/P2P1P2/8/8/K7 w - - 0 1 moves a1a2 a7a8 a2a1
The old code suggested a loosing move "bestmove a8a7", the new code suggests "bestmove a8b7" leading to a draw.
Incorrect evaluation (happened in a real game in TCEC Season 9).
position fen 4rbkr/1q3pp1/b3pn2/7p/1pN5/1P1BBP1P/P1R2QP1/3R2K1 w - - 5 31 moves e3d4 h8h6 d4e3
The old code evaluated it as "cp 0", the new code evaluation is around "cp -50" which is adequate.
Brings 0.5-1 ELO gain. Passes [-3.00,1.00].
STC: http://tests.stockfishchess.org/tests/view/584ece040ebc5903140c5aea
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 47744 W: 8537 L: 8461 D: 30746
LTC: http://tests.stockfishchess.org/tests/view/584f134d0ebc5903140c5b37
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 36775 W: 4739 L: 4639 D: 27397
Patch has been rewritten into current form for simplification and
logic slightly changed so that return a draw score if the position
repeats once earlier but after or at the root, or repeats twice
strictly before the root. In its original form, repetition at root
was not returned as an immediate draw.
After retestimng testing both version with SPRT[-3, 1], both passed
succesfully, but this version was chosen becuase more natural. There is
an argument about MultiPV in which an extended draw at root may be sensible.
See discussion here:
https://github.com/official-stockfish/Stockfish/pull/925
For documentation, current version passed both at STC and LTC:
STC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 51562 W: 9314 L: 9245 D: 33003
LTC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 115663 W: 14904 L: 14906 D: 85853
bench: 5468995
Non-functional changes
a) splitting the threat array to avoid using an enum
b) reorder the scores according to functions where they are used.
c) declarations in evaluate_pieces after the const(s) like elsewhere
d) more compact definitions of KingFlank,
now that we need it also for the PanwLessFlank penalty.
e) reuse CenterFiles in evaluate_space
f) move one line inside next popcount
No functional change.
It was a bit of a hack, without intrinsic value, but rather compensating for the
fact that checks were mistuned.
STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 88308 W: 15553 L: 15545 D: 57210
LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 53115 W: 6741 L: 6662 D: 39712
bench 5468995
Fixes the only exception, in razoring.
The code already does assert(PvNode || (alpha == beta - 1)), and it can be verified by studying the program flow that this is indeed the case, also for the modified line.
No functional change.
