Added the UCI_LimitStrength and the UCI_Elo options, with an Elo
range of 2100-2900. When UCI_LimitStrength is enabled, the number
of threads is set to 1, and the search speed is slowed down according
to the chosen Elo level.
Todo:
1. Implement Elo levels below 2100 by blundering on purpose and/or
crippling the evaluation.
2. Automatically calibrate the maximum Elo by measuring the CPU speed
during program initialization, perhaps by doing some bitboard
computations and measuring the time taken.
No functional change when UCI_LimitStrength is false (the default).
It is like a never finished painting. Everyday a little touch
more.
But this time it is very little ;-)
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Small micro-optimization in this very
time critical function.
Use bitwise 'or' instead of logic 'or' to avoid branches
in the assembly and use the result to skip an handful of checks.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Verified it is equivalent to the tuning branch results
with parameter values sampled after 100.000 games.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Some unwanted changes to Makefile slept in in patch
"Introduced the UCI_AnalyseMode option".
Revert them. No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This is more similar to how get_material_info() and
get_pawn_info() work and also removes some clutter from
evaluate_king().
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
When ordering moves we push all captures with negative SEE values
to badCaptures[] array during the scoring phase.
This patch delays the costly SEE call up to when the move has been
picked up in pick_move_from_list(), this way we save some SEE calls
in case we get a cutoff.
It seems we have a speed gain of about 1-1.5 % in terms of nodes/sec
and profiling seems to confirm the small but real speed increase.
Idea from Pablo Vazquez on talkchess.com
http://www.talkchess.com/forum/viewtopic.php?t=29018&start=20
It would be a no functional change but actually it is not because
now sorting set is different and so std::sort(), that is not a
stable sort, does not guarantees the order of same scored moves to
remain the same as before.
After 952 games at 1+0 we are below error bar, almost equal just
6 games of difference (+2 ELO)
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Do not call count_1s_max_15() if not necessary, as is
not in the common case (>95%).
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Use a polynomial weighted evaluation to calculate
material value.
This is far more flexible and elegant then applying
a series of single euristic rules as before.
Also correct a design issue in which we returned two
values, one for middle game and one for endgame, while
instead, because game phase is a function of board
material itself, only one value should be calculated and
used both for mid and end game.
Verified it is equivalent to the tuning branch results with
parameter values sampled after 40.000 games.
After 999 games at 1+0
Mod vs Orig +277 =482 -240 51.85% 518.0/999 +13 ELO
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
To use the same naming rule of the other types and
to be compatible with inttypes.h, used under Linux.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
We do not accept null search returned mate values,
but we always do a full search in those cases.
So the variable mateThreat that is set only if null move
search returns a mate value is always false.
Restore the functionality of mateThreat moving the
assignement where it can be triggered.
After 999 games at 1+0
Mod vs Orig +253 =517 -229 51.20% +8 ELO
Bug reported by xiaozhi
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Tord says that using a lower horizon at PV nodes
looks strange and inconsistent with the general
philosophy of our search (i.e. always being more
conservative at PV nodes). So set LMR at 3 also
on search_pv().
Test result after 601 games seems to confirm this.
Mod vs Orig +156 =318 -127 52.41% 315.0/601 +17 ELO
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Test extension of LMR horizon to 3 plies alone, without
touching null move search. To keep the patch minimal we still
don't change LMR horizon in PV search. This will be the object
of the next patch.
Result seems good after 998 games:
Mod vs Orig +252/=518/-228 51.20% 511.0/998 +8 ELO
So dynamic null move reduction seems a bit stronger then
fixed reduction even with LMR horizon set to 3.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Revert to LMR horizont of 2 plies. Only if parent move
is a null move increase to 3 so to avoid the bad combination
of null move reduction + LMR reduction. This is a more
aggressive patch then previous one, but it seems we are
going in the wromg direction.
After 531 games result is not good:
Mod vs Orig +123/=265/-143 48.12% 255.5/531 -13 ELO
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Set null move reduction to R=4, but increase the LMR horizon
to 3 plies. The two tweaks are related and should compensate
the combined effect of null move + LMR reduction at shallow
depths.
Idea from Tord.
After 999 games at 1+0
Mod vs Orig +251 =522 -225 51.30% + 9 ELO
On Tord iMac Core 2 Duo 2.8 GHz, one thread,
Mac OS X 10.6, at 1+0 time control we have:
Mod vs Orig 994-1006 -1.4 ELO
But Orig version is pgo compiled and Mod is not.
The PGO compiled version is about 8% faster, which
corresponds to about 7 Elo points. This means that
results are reasonably consistent.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Code that compiles cleanly under MSVC triggers one
compile error (correct) under Intel C++ and two(!)
under gcc.
The first is the same complained by Intel, but the second
is an interesting corner case of C++ standard (there are many)
that is correctly spotted only by gcc.
Both MSVC and Intel pass this silently, probably to avoid
breaking people code.
Now we are fully C++ compliant ;-)
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This avoid to duplicate storage allocation for every file
where they are used.
Note that simple numeric constant can remain in header because
are automatically folded by the compiler.
Patch suggested by Tord.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Push on the templatization even more to chip out some code
and take the opportunity to show some neat template trick ;-)
Ok. I would say we can stop here now....it is quickly becoming
a style exercise but we are not boost developers so give it a stop.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
a static eval cached in the transposition table would always equal the static
eval of the current position. This is in general not true, because the cached
value could be from a previous search with different evaluation parameter
settings, or from a search from the opposite side (Stockfish's evaluation
function is assymmetric by default).
We really don't need to have global endgame functions. We can
allocate them on the heap at initialization time and store the
corresponding pointer directly in the functions maps. To avoid
leaks we just need to remember to deallocate them in map d'tor.
These functions are always created in couple, one for each color,
so remove a lot of redundant hard coded info and just use the minimum
required: the type and the corresponding named string.
This greatly simplifies the code and also it is less error prone,
now is much simpler to add a new endgame specialized function: just
add the corresponding enum in endgame.h and the obvious add_xx()
call in EndgameFunctions c'tor, and of course, the most important part,
the EvaluationFunction<xxx>::apply() specialization in endgame.cpp
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This feature makes sense during development, but
It doesn't seem to make sense for normal users.
Also fix a possible race where the GUI adjudicates
the game a fraction of second before the engine sets
looseOnTime flag so that it will bogusly waits until
it ran out of time at the beginning of the next new game.
The fix is to always reset looseOnTime at the beginning
of a new game.
Race condition spotted by Tord.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This is another moves serialization macro but this time
focused on pawn moves where the 'from' square is given as
a delta from the 'to' square.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
It is very rare we have pawns on 7(2) rank, so we
can skip the promotion handling stuff in most cases.
With this patch pawn moves generation is almost 20% faster.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Mostly of times we are interested only in the sign of SEE,
namely if a capture is negative or not.
If the capturing piece is smaller then the captured one we
already know SEE cannot be negative and this information
is enough most of the times. And of course it is much
faster to detect then a full SEE.
Note that in case see_sign() is negative then the returned
value is exactly the see() value, this is very important,
especially for ordering capturing moves.
With this patch the calls to the costly see() are reduced
of almost 30%.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Some variables were global due to some old and now removed code,
but now can be moved in local scope.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Verification test give unusless result
After 999 games at 1+0
Mod vs Orig +250 =503 -246 50.20% +1 ELO
So we are well below our radar level. Neverthless
there are 100.000 games on Joona QUAD that we could
take in account and that shows that this tweak perhaps
has something good in it, altough very little.
Verification tests shows should not be a regression, at
least not a big one even in the worst case, so apply the
change anyway and keep the finger crossed ;-)
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
It turned out that the input sent to set_option_value() when it is called by
set_option() in uci.cpp always started with at least one whitespace. In most
cases, this is not a problem, because the majority of UCI options have numeric
values. It did, however, cause a problem for UCI options with non-numerical
values, like options of type CHECK and COMBO. In particular, changing the
value of an option of type CHECK didn't work, because the comparisons with
"true" and "false" would always return false. This means that the "Ponder"
and "UCI_Chess960" options haven't been working for a while.
Unfortunatly this tweak does not give good results.
After 894 games at 1+0 we have:
Mod vs Orig +205/-236/=453 48.27% -12 ELO !!
Perhaps we should test again, but in the mean time
we are going to revert this.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
A promotion move is not considered a possible evasion as it could be.
Bug introduced by patch
Convert also generate_pawn_blocking_evasions() to new API (7/5/2009)
Bug spotted by Kenny Dail.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Set gcc as default compiler on Linux, also compile
with symbols stripped to shrink binary file.
Original patch by Heinz van Saanen.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Predefined macro __INTEL_COMPILER is defined only for Intel,
while _MSC_VER is defined for both Intel C++ and MSVC.
So rearrange ifdefs to take in account this and test __INTEL_COMPILER
first and only if not defined check _MSC_VER for MSVC.
Patch suggested by Joona.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Add a new argument to bench to specify the name of the
file where timing information will be saved for each
benchmark session.
This argument is optional, if not specified file will
not be created.
Original patch by Heinz van Saanen
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This is mainly intended to allow 64 bit compiles on any
system and avoid to crash when the binary, compiled on a
box where POPCNT is not supported, is run on a Core i7
system or similar CPU.
What could happen is that when compiled in a standard 64 bit
system, because the correct headers for the POPCNT intrinsic
are not found, the compiler creates dummy bit count functions
instead, these are never called at runtime on the machine where
Stockfish has been compiled. But if we run the same binary on a
Core i7 system, because POPCNT is detected at run time, the dummy
bitcount functions will be called giving false results that will
crash the application.
Note that would be possible to fallback on software bit count in
these cases, but this is even more subtle because POPCNT path is not
optimized so that we have an application working but at sub-optimal
speed, so better to crash, at least user is loudly warned that there
is something wrong.
If, instead, Stockfish is compiled on a Core i7 system with POPCNT
enabled, then if the PGO compile has been done properly, the same binary
will run at optimal speed _both_ on the Core i7 machine and on any other
64 bit standard machine. This is the ideal mode for binary distribution.
Finally this patch disables bsfq support under Windows, because it seems
inline assembly is not supported both by MSVC and by Intel Windows version.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Also rename DISABLE_POPCNT_SUPPORT in NO_POPCNT and simplify a bit
the macro logic.
Always define a __popcnt64()or _mm_popcnt_u64() template, if the proper
function with the same name is defined in the intrinsics header, then it
will be choosen as first otherwise we fall back on the dummy template
that is never called at runtime anyway because cpu_has_popcnt() returns
false.
This fixes the compile error reported by Jim.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Avoid indirect calling of piece_of_color_and_type(c, PAWN) and its
alias pawns(c) in the pawn evaluation loop, but use the pawns
bitboards accessed only once before entering the loop.
Also explicitly mark functions as static to better self-document.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Was erroneusly changed with the 32bit in recent
patch "Retire USE_COMPACT_ROOK_ATTACKS...".
Also another clean up of define magics. Move compiler
specific definitions in types.h and remove redundant cruft.
Now this macro ugly mess seems more reasonable.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
On 64 bit systems we can use bsfq instruction to count
set bits in a bitboard.
This is a patch for GCC and Intel compilers to take advantage
of that and get a 2% speed up.
Original patch from Heinz van Saanen, adapted to current tree
by me.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This greatly simplifies bitboard.cpp that now has only two setups,
respectively for 32 and 64 bits CPU according to IS_64BIT define
that is automatically set but can be tweaked manually in
bitboard.h
No functional change both in 32 and in 64 bits.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
