The idea is to fail high more easily in static
null test if in the parent node we are already
very deep in the move list, so the propability
to fail high there is very low.
[edit: I have slightly changed the functionality
moving
ss->futilityMoveCount = moveCount;
At the end of the pruning code, this should not affect
ELO in anyway, but makes code more natural and logic]
Test with SPRT is good at 15+0.05
LLR: 2.96 (-2.94,2.94)
Total: 50653 W: 10024 L: 9780 D: 30849
And at 60+0.05
LLR: 2.97 (-2.94,2.94)
Total: 40799 W: 7227 L: 6921 D: 26651
bench: 4530093
This reverts commit 0d68b523a3.
After easy move semplification this machinery is not
needed anymore (because of we don't need to know if a
root move is a recapture)
No functional change.
Rename to insertion_sort so to avoid confusion
with std::sort, also move it to movepicker.cpp
and use the bit slower std::stable_sort in
search.cpp where it is used in not performance
critical paths.
No functional change.
Following a user request I added the handling of UCI:
go mate x
Currently we just return from a PV node if x moves have been
done. Probably not the best approach. I have looked at Fruit/Toga
sources and there is even simpler: engine falls back on a fixed
depth search.
No functional change.
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>
In particualr before to wake up main thread that
could take some random time. Until we don't reset
search time we are not able to correctly track
the elapsed search time and this can be dangerous
under extreme time pressure.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
There is no need to "invent" different names
from the original UCI parameters.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
And introduce SPlitPoint bestMove to pass back the
best move after a split point.
This allow to define as const the search stack passed
to split.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
And directly pass RootMoves instead of SearchMoves
to main thread. A class declaration is better suited
in a header and slims a bit the fatty search.cpp
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
We just need to verify if a legal move is among the
SearchMoves, so we don't need a vector for this.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
We try hard not to lose on time even under extreme
time pressure. We achieve this through 3 different but
coordinated steps:
1) Increase max frequency of timer events
2) Quickly return after a stop signal
3) Take in account timer resolution
With these SF played under LittleBlitzer at 1"+0.02 and 3"+0
without losing on time even one game.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Diretcly use the underlying std::vector<Move> and the
STL algorithms. Also a bit of cleanup while there.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Detach from the UI thread the input arguments used by
the search threads so that the UI thread is able to receive
and process any command sent by the GUI while other threads
keep searching.
With this patch there is no more need to block the UI
thread after a "stop", so it is a more reliable and
robust solution than the previous patch.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Move global search-related variables under "Search" namespace.
As a side effect we can move uci_async_command() and
wait_for_stop_or_ponderhit() away from search.cpp
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Use the starting thread to wait for GUI input and instead use
the other threads to search. The consequence is that now think()
is alwasy started on a differnt thread than the caller that
returns immediately waiting for input. This reformat greatly
simplifies the code and is more in line with the common way
to implement this feature.
As a side effect now we don't need anymore Makefile tricks
with sleep() to allow profile builds.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
The timer will be fired asynchronously to handle
time management flags, while other threads are
searching.
This implementation uses a thread waiting on a
timed condition variable instead of real timers.
This approach allow to reduce platform dependant
code to a minimum and also is the most portable given
that timers libraries are very different among platforms
and also the best ones are not compatible with olds
Windows.
Also retire the now unused polling code.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Node count is different just becuase now we don't log on
"bench.txt" file anymore so that we avoid some calls to
pretty_pv() that calls Position::do_move().
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This change allows to remove some quite a bit of code
and seems the natural thing to do.
Introduced file thread.cpp to move away from search.cpp a lot
of threads related stuff.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Shrink search() signature for better readibility.
We get also a nice 1.3% speed increase.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
And also store the node counter in Position and not in Thread.
This will allow to properly count nodes also in sub trees with
SMP active.
This requires a surprisingly high number of changes
in a lot of places to make it work properly.
No functional change but node count changed for obvious reasons.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
It has more sense to treat the two evaluation metrics
in the same way.
As a side effect now we use the correct eval margin when
pruning in a SplitPoint node.
No functional change in single thread.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
It has more sense to treat the two evaluation metrics
in the same way.
As a side effect now we use the correct eval margin when
pruning in a SplitPoint node.
No functional change in single thread.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Rewrite sp_search() to have same signature of search()
This is the first prerequistite step toward unification.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Let be explicit about what this functions do, and
we save some code lines too.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
After we set ss->threatMove we could go under a IID step that
resets SearchStack ss and so also ss->threatMove.
When later we use that field in futility pruning we have this
set to MOVE_NONE !
The fix is to use a local variable and add threatMove to SplitPoint
to pass this move to slaves.
Spotted by Ralph Stoesser, fix suggested by Richard Vida.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
