We can have ttValue == VALUE_NONE when we use a TT
slot to just save a position static evaluation, but
in this case we also save DEPTH_NONE so to avoid
using the ttValue in search. This happens to work,
but due to a number of lucky and tricky cases that
we now documnet through a bunch of asserts and a
little change to value_from_tt() that has no real
effect but clarifing the code.
No functional change.
On some platforms 128 MB of RAM for TT is too much,
so run 'bench' with the default 32 MB size.
No functional change although of course now 'bench'
reports a different number: 5545018
Use popcount() instead in the only calling place.
It is used only at initialization so there is no
speed regression and anyhow even initialization
itself is not slowed down: magic bitboard setup
stays around 175 msec on my slow 32bit Core Duo.
No functional change.
Simplify the code and doing this introduce a couple
of (very small) functional changes:
- Always compare to depth even in "mate value" condition
- TT cut-off in qsearch also in case of PvNode, as in search
Verified against regression with 2500 games at 30"+0.05
on 2 threads: 451 - 444 - 1602
Functional changed: new bench is 5544977
As Joona says: "The problem is that when doing full
window search (-VALUE_INFINITE, VALUE_INFINITE), and
pruning all the moves will return fail low which is
mate score, because only clause touching alpha is
"mate distance pruning". So we are returning mate score
although we are just pruning all the moves. In reality
there probably is no mate in sight.
Bug spotted and fixed by Joona.
Port to qsearch() the same changes we recently
added to search().
Overall this search refactoring series shows
almost 2% speed up on gcc compile.
No functional change.
When using the Makefile (as for the mingw case),
IS_64BIT and USE_BSFQ are already set with
ARCH=x86-64 and do not need to be redefined.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
First disable Contempt Factor during analysis, then
calculate the modified draw score from the point of
view of the player, so from the point of view of
RootPosition color.
Thanks to Ryan Taker for suggesting the fixes.
No functional change.
These kind of arch specific code is really nasty
to make it right becuase you need to verify on
all the platforms.
Now should compile properly also on ARM
Reported by Jean-Francois.
No functional change.
A simplification and also a small speed-up of
about 1% mainly due to reducing calls to
thisThread->cutoff_occurred().
Worst case split point recovering time after a
cut-off occurred is limited to 3 msec on my slow
PC, and usually is below 1 msec, so it seems safe
to remove the cutoff_occurred() check.
No functional change.
This is very crude and very basic: simply in case
of a draw for repetition or 50 moves rule return
a negative score instead of zero according to the
contempt factor (in centipawns). If contempt is
positive engine will try to avoid draws (to use
with weaker opponents), if negative engine will
try to draw. If zero (default) there are no changes.
No functional change.
Use a value related to PawnValue instead.
This is a different patch from previous one because
could affect game play and skill levels, although
in a mostly unmeasurable way. Indeed thresold has
been raised so easy move is a bit harder to trigger
and skill level is a bit more prone to blunders.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Show the real value in the code, not hide it
behind a variable name, especially when there
is only once occurence.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Extend for an extra half-ply in case the node is (probably)
going to fail high. In this case the added overhead is limited.
A novelity is the way this patch has been tested: Always in
self-play but with a much longer TC to allow the singular
extension to fully kick in and also (my impression) to have
less noisy results.
Ater 1015 games on my QUAD at 60"+0.05
Mod vs Orig 173 - 150 - 692 ELO +8
Handle also the SMP case. This has been quite tricky, not
trivial to enforce the node limit in SMP case becuase
with "helpful master" concept we can have recursive split
points and we cannot lock them all at once so there is the
risk of counting the same nodes more than once.
Anyhow this patch should be race free and counted nodes are
correct.
No functional change.
As long as isPvMove (renamed to pvMove) is set after
legality check, we can postpone legality even in PV case.
Patch aligns the PV case with the common non-pv one.
No functional change.
We have a crash with this position:
rkqbnnbr/pppppppp/8/8/8/8/PPPPPPPP/RKQBNNBR w HAha -
What happens is that even if we are castling QUEEN_SIDE,
in this case we have kfrom (B8) < kto (C8) so the loop
that checks for attackers runs forever leading to a crash.
The fix is to check for (kto > kfrom) instead of
Side == KING_SIDE, but this is slower in the normal case of
ortodhox chess, so rewrite generate_castle() to handle the
chess960 case as a template parameter and allow the compiler
to optimize out the comparison in case of normal chess.
Reported by Ray Banks.
Broken by commit a44c5cf4f7 of 3 /12 / 2011 that
was labeled "No functional change" because our 'bench'
test didn't triggered that particular endgame. Indeed
we need to run a specific bench on a set of endgames
position when touching endgame.cpp because normal bench
does not cover endgames properly.
Found by MSVC 2012 code analyzer.
It seems Intel is unable to properly workout templates with 'static'
storage specifier.
Workaround using an anonymous namespace instead.
No functional change.
Currently we exit the loop when
abs(bestValue) >= VALUE_KNOWN_WIN
but there is no logical reason for this. It seems more
natural to re-search again with full open window.
This has practically no impact in most cases, we have a
'no functional change' running 'bench' command.
The trick here is to check for legality only in the
(rare) cases we have pinned pieces or a king move
or an en-passant.
This trick is able to increase the speed of perft
of more then 20%!
No functional change.
Simply reshuffling the code inverting the condition in next_attacker()
yields a miraculous speed up of more than 3% under gcc!
On my laptop a bench run goes from 320Knps to 330Knps
No functional change.
This allows to reduce the scanning for new X-ray attacks
according to the capturing piece type.
It seems to be just a very small speed increase in MSVC 64
bit and gcc 32 bit, I guess cache issues value more than some
instruction less to execute (as usual).
No functional change.
It is very difficult and risky to assure
that a running thread doesn't access a global
variable. This is currently true, but could
change in the future and we don't want to rely
on code that works 'by accident'. The threads
are still running when ThreadPool destructor is
called (after main() returns) and this could
lead to crashes if a thread accesses a global
that has been already freed. The solution is to
use an exit() function and call it while we are
still in main(), ensuring global variables are
still alive at threads termination time.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
When many threds concurrently print you need to serialize
the access to std::cout to avoid output lines are intermixed
with the contents of each thread.
This is not strictly needed at the moment because
only main thread prints out, although some ad-hoc
test could trigger UCI::loop() printing while searching.
Anyhow we want to lift this pretty avoidable constrain
also as a prerequisite for future work.
This patch just introduces the support, next one will enable
the serialization.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Before the search we setup the starting position doing all the
moves (sent by GUI) from start position to the position just
before to start searching.
To do this we use a set of StateInfo records used by each
do_move() call. These records shall be kept valid during all
the search because repetition draw detection uses them to back
track all the earlier positions keys. The problem is that, while
searching, the GUI could send another 'position' command, this
calls set_position() that clears the states! Of course a crash
follows shortly.
Before searching all the relevant parameters are copied in
start_searching() just for this reason: to fully detach data
accessed during the search from the UCI protocol handling.
So the natural solution would be to copy also the setup states.
Unfortunatly this approach does not work because StateInfo
contains a pointer to the previous record, so naively copying and
then freeing the original memory leads to a crash.
That's why we use two std::auto_ptr (one belonging to UCI and another
to Search) to safely transfer ownership of the StateInfo records to
the search, after we have setup the root position.
As a nice side-effect all the possible memory leaks are magically
sorted out for us by std::auto_ptr semantic.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Should be more clear from where the 'magic' numbers
come from.
Also bit of reformat while there.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Instead of just size(). Although code is longer,
should be more immediate to understand when reading.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
To mimics C++11 std::mutex and std::condition_variable,
also rename locks and condition variables to be more
uniform across the classes.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Reduce of one instruction. It seems a tad faster on
the profiler now. Very slightly but anyhow it is a
code semplification.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This better mimics std::vector::operator[] and
fixes a warning with MSVC 64bit.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Further reduce redundancy in move generation.
Veirifed no speed regression on MSVC, Clang and gcc.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Greatly simplify these very performace critical functions.
Amazingly we don't have any speed regression actually under
MSVC we have the same assembly for generate_moves() !
In generate_direct_checks() 'target' is calculated only
once being a loop invariant.
On Clang there is even a slight speed up.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Are used by Position but do not belong to that class,
there is only one instance of them (that's why were
defined as static), so move to a proper namespace instead.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Check we are the last slave of the split point
before to wake up the master. This should avoid
spurious wakes up.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
We can detect the split point master also from within idle_loop,
so we can call the function without parameters and remove an
overloaded member hack in Thread class.
Note that we don't need to take a lock around curSplitPoint
when entering idle_loop() because if we are the master then
curSplitPoint cannot change under our feet (because is_searching
is set and so we cannot be reallocated), if we are a slave
we enter idle_loop() only upon Thread creation and in that case
is always splitPointsCnt == 0. This is true even in the very rare
case that curSplitPoint != NULL, if we have been already allocated
even before entering idle_loop().
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Directly use the underlying std::map instead and avoid
a useless inheritance.
As a nice side-effect Options global object has now a
default c'tor avoiding possible issues with globals
initializations.
Suggested by Rein Halbersma.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Templetize MovePicker::next_move() member function instead. It
is easier and we also avoid the forwarding of MovePicker() c'tor
arguments in the common case.
Suggested by Rein Halbersma.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
And group there all the formatting functions but
uci_pv() that requires access to search.cpp variables.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Use the helpers to format the PV info but without
writing to output stream (file or cout). Message
formatting and sending are two logically different
task.
Incidentaly reintroduce the pretty_pv() name,
from Glaurung memories :-)
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Simplifies the code and seems more natural.
We have a very small fucntional change becuase now
at PV nodes castles are extended one ply anyhow.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
With warning level 4 MSVC complains that a default
assignment operator could not be generated due to
member 'file' is a reference (warning C4512).
Use a pointer instead of a reference and move
struct Tie outisde class Logger while there.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
It seems more accurate: lsb is clear while 'first
bit' depends from where you look at the bitboard.
And fix compile in case of 64 bits platforms that
do not use BSFQ intrinsics.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Instead of -O4 option that does not work with both mingw and
Linux gcc (tested with Clang 3.1).
As reported by Reed Kotler:
Turns out that -O4 is not a valid option for clang unless you have
the proper gold linker and plugins built. That's because -O4 enables
LTO, which writes out bitcode files during the compile, and then loads
those and optimizes them during the link phase.
It requires a linker that supports LLVM's LTO. There is a plugin for
Gold available as part of LLVM.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
We have a signed integer here so let the return type
take in account that.
Found by Clang with -Weverything option.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Return a reference instead of void so to enable
chained assignments like
"p = q = Position(...);"
Suggested by Rein Halbersma.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Although a (little) functional change, we have no ELO change
but formula it is now more clear.
After 13019 games at 30"+0.05
Mod vs Orig 2075 - 2088 - 8856 ELO 0 (+- 3.4)
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
It seems the standard behaviour as implemented
in most engines although UCI protocol does not
specify what to do upon "ucinewgame" command.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Calculate the attacks only for the piece to disambiguate,
not for all.
Also some reformatting while there.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Marco Costalba