There is no reason to compile 3 different copies of search(). PV nodes are on
the cold path, and PvNode is a template parameter, so there is no cost in
computing:
const bool RootNode = PvNode && (ss-1)->ply == 0;
And this simplifies code a tiny bit as well.
Speed impact is negligible on my machine (i7-3770k, linux 4.2, gcc 5.2):
nps +/-
test 2378605 3118
master 2383128 2793
diff -4523 2746
Bench: 7751425
No functional change.
Resolves#568
In case of a very high material score, we can
overflow VALUE_INFINITE.
This patch fixes an assert with:
position fen 7k/QQQQR3/2B5/4KN1Q/3QQ3/8/8/4R3 b - - 0 1
go depth 1
No functional change.
Resolves#546
Make it explicit that those variables are not globals, but
are used only by main thread. I think it is a sensible
clarification because easy move is already tricky enough
and current patch makes the involved actors explicit.
No functional change.
Resolves#537
Tuned the global mobility factor for each piece, as well as some +- delta,
The master mobility factor was {266,334} and tuning gave
{267, 362} +S(-2,-2) for the Knight
{249, 328} +S( 0,-2) for the Bishop
{298, 353} +S(1,1) for the Rook
{265, 358} +S(2,-1) for the Queen
Passed STC
LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 49402 W: 9367 L: 9037 D: 30998
and LTC
LLR: 2.97 (-2.94,2.94) [0.00,5.00]
Total: 26831 W: 3871 L: 3658 D: 19302
Bench: 8355485
Resolves#536
Fix a bug where we could stop the search after only 10% of time used due to a matching easy move but later switch to a different move that was never pre-screened as easy due to SMP thread select.
STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 27227 W: 4910 L: 4800 D: 17517
LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 40368 W: 5826 L: 5733 D: 28809
Resolves#521
Simplify time management code by removing hard stops for unchanging first root moves.
Search is now stopped earlier at the end iteration if it did not have fail-lows at root.
This simplification also fixes pondering bug. Ponder flag was true by default
and cutechess-cli doesn't change it to false even though no pondering is possible.
Fix the issue by setting the default value of 'Ponder' flag to false.
10+0.1:
ELO: 3.51 +-3.0 (95%) LOS: 99.0%
Total: 20000 W: 3898 L: 3696 D: 12406
40+0.4:
ELO: 1.39 +-2.7 (95%) LOS: 84.7%
Total: 20000 W: 3104 L: 3024 D: 13872
60+0.06:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 37231 W: 5333 L: 5236 D: 26662
Stopped run at 100+1:
LLR: 1.09 (-2.94,2.94) [-3.00,1.00]
Total: 37253 W: 4862 L: 4856 D: 27535
Resolves#523Fixes#510
Also inline defintions of SpaceMask and CenterBindMask.
Verified from assembly that compiler computes the values
at compile time, so it is also theoretical faster.
While there factor out scale factor evaluation.
No functional change.
This is used by std::stable_sort() to sort moves from highest score to lowest score.
1) The comment is incorrect since highest to lowest means descending.
2) It's more natural to implement a less operator using another less operator rather than a greater operator.
No functional change.
Resolves#504
Comment is based on a misunderstanding of what unaligned memory access is. Here
is an article that explains it very clearly:
https://www.kernel.org/doc/Documentation/unaligned-memory-access.txt
No matter how we define TTEntry or TTCluster, there will never be any unaligned
memory access. This is because the complier knows the alignment rules, and does
the necessary adjustments to make sure unaligned memory access does not occur.
The issue being adressed here has nothing to do with unaligned memory access. It
is about cache performance. In order to achieve best cache performance:
- we prefetch the cacheline as soon as possible.
- we ensure that TT clusters do not spread across two cachelines. If they did,
we would need to prefetch 2 cachelines, which could hurt cache performance.
Therefore the true conditions to achieve this are:
1/ start adress of TT is cache line aligned. void TranspositionTable::resize()
enforces this.
2/ TT cluster size should *divide* the cache line size. Currently, we pack 2
clusters per cache lines. It used to be 1 before "TT sardines". Does not matter
what the ratio is, all we want is to fit an integer number of clusters per cache
line.
No functional change.
Resolves#506
Instead of creating a running std::thread and
returning, wait in Thread c'tor that the native
thread of execution goes to sleep in idle_loop().
In this way we can simplify how search is started,
because when main thread is idle we are sure also
all other threads will be idle, in any case, even
at thread creation and startup.
After lazy smp went in, we can simpify and rewrite
a lot of logic that is now no more needed. This is
hopefully the final big cleanup.
Tested for no regression at 5+0.1 with 3 threads:
LLR: 2.95 (-2.94,2.94) [-5.00,0.00]
Total: 17411 W: 3248 L: 3198 D: 10965
No functional change.
Now that we don't have anymore TimerThread, there is
no need of this long class hierarchy.
Also assorted reformatting while there.
To verify no regression, passed at STC with 7 threads:
LLR: 2.97 (-2.94,2.94) [-5.00,0.00]
Total: 30990 W: 4945 L: 4942 D: 21103
No functional change.
