This will allow to have wider access to attack
information, for instance from MovePicker.
Note that 'eval' field become obsolete, it is kept
just becasue when we get a position score from TT
we update 'eval' even without an EvalInfo object.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
In sp_search_pv() we do a LMR search using sp->alpha, at the end
we detect a fail high with condition (value > sp->alpha), but if
another thread has increased sp->alpha during our LMR search we
could miss to detect a fail high event becasue value will be equal
to old alpha and so smaller then new one.
This patch fixes this SMP-bug and changes also the non SMP versions
of the search to keep code style in sync.
Bug spotted by Bruno Causse.
No functional change (for single CPU case)
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
futilityValue is now calculated immediately after
staticValue, so remove small bunch of unused code
No functional change
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
MSVC raises an "use of partially uninitialized variable" for futilityValue
and staticValue but this is not rue becasue when !isCheck variables
are never used, anyhow silence the warning.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This is less prone to bugs because now it's up to the
compiler don't forget this important initialization.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
No change in functionality signature
The only functional change is that when we reach PLY_MAX,
we now return VALUE_DRAW instead of evaluating position.
But we reach PLY_MAX only when position is dead drawn and
transposition table is filled with draw scores, so this
shouldn't matter at all.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This way razoring is always based on exact evaluation and
follows simple formula.
Joona's test results are positive:
32-bit 1CPU:
Mod - Orig: 1073 - 993
64-bit 4CPU:
Mod - Orig: 759 - 721
Functionality Signature: 11448962
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Don't clamp to zero if a move continues to fail.
After 946 games at 1+0
Mod vs Orig +208 =562 -176 +12 ELO
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Also retire razoring margins vector and use
a simpler formula instead.
Now that we use a more accurate static evaluation
try to avoid useless null searches when we are well
below beta. And for teh same reason increase a bit
the razoring.
After 972 games at 1+0
Mod vs Orig +224 =558 -190 +12 ELO
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
It means we have already received "stop" or "quit" commands.
This fixes an hang in tactical test in Fritz GUI. Bug
introduced by previous bug fix :-(
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
According to UCI standard once engine receives 'go infinite'
command it should search until the "stop" command and do not exit
the search without being told so, even if PLY_MAX has been reached.
Patch is quite invasive because it cleanups some hacks used
by fixed depth and fixed nodes modes, mainly during benchmarks.
Bug found by Pascal Georges.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
After deep tests Louis Zulli found on his OCTAL machine that
best setup for an 8 core CPU is as following
"Threads" = 8
"Minimum Split Depth" = 6 or 7 (mSD)
"Maximum Number of Threads per Split Point" = not important (MNTpSP)
Here are testing results:
mSD7 (8 threads) vs mSD4 (8 threads): 291 - 120 - 589
mSD6 vs mSD7: 168 - 188 - 644
mSD6-MNTpSP5 vs mSD6-MNTpSP6: 172 - 172 - 656
SF-7threads vs SF-8threads: 179 - 204 - 617
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
So to have the same layout and be as much similar as
possible. The only functional change is that now we
try ttMove as first also in PV nodes and at the end
we save the ttMove, as it happens in search. This
should have almost zero impact on ELO but it seems
the correct thing to do.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This is an important design change because we know
compute evaluation in each node.
This is a 2.0 type change!
After 977 games at 1+0
Mod vs Orig +236 =538 -202 51.74% +12 ELO
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
If after 'moves' there is a space then we crash.
The problem is that operator>>() trims whitespaces so that
after 'moves' has been extract we are still not at eof()
but remaining string contains only spaces. So that the next
extarction operation uip >> token ends up with unchanged token
value that remains 'moves', this garbage value is then feeded
to RootPosition.do_move() through move_from_string() that does
not detect the invalid move value leading to a crash.
This bug is triggered by Shredder 12 interface under Mac that
puts a space after 'moves' without any actual move list.
Bug fixed by Justin Blanchard
After reviewing UCI parsing code I spotted other possible weak
points due to the fact that we don't test if the last extract
operation has been succesful. So I have extended Justing patch
to fix the remaining possible holes in uci.cpp
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
According to standard en-passant is recorded in fen string regardless
of whether there is a pawn in position to make an en passant capture.
Instead internally we set ep square only if the pawn can be captured.
So teach from_fen() to correctly handle this difference.
Bug reported and fixed by Justin Blanchard.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Try to get a position evaluation better then
the quick one with the help of the TT table.
This allows the null search conditions and
chosen reductions to be more accurate.
After 908 games at 1+0
Mod vs Orig +209 =526 -173 +14 ELO
Functionality Signature: 16627355
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Linear rule, less aggressive then Dann's one.
It seems it scales well with depth. We will need to
verify against weaker engine if it keeps the score.
After 999 games at 1+0 on my Dual Core
Mod vs Orig +232 =534 -207 +9 ELO
After 1000 games by Martin Thoresen on his QUAD at 1+0
Mod vs Orig 521/479 52.10%
Functionality Signature: 17655312
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
The most interesting thing is a bit of rewrite
and semplification in connected_moves()
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
It is not useful becasue it is safe to call
get_next_move() multiple times when phase == PH_STOP
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Because that's the correct meaning. Note that also the
corresponding UCI option has been renamed.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
After history accounting rewrite in 1.6, a small
tweak of history parameters seems positive.
Note that these are not to be considered the optimal
values, just a wild guess that proved good.
Finding the optimal values would require a much longer
testing time.
After 967 games at 1+0
Mod vs Orig 240 529 198 +15 ELO
Functionality Signature: 21222553
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
According to the standard, compiler is free to choose
the enum type as long as can keep its data.
Also cast to short and right shift are implementation
defined in case of a signed integer.
Normally all the compilers implement this stuff in
the "usual" way, but gcc with -O3 and -O2 pushes
aggressively the language to its limits to squeeze
even the last bit of speed. And this broke our
not 100% standard conforming code.
The fix is to rewrite the Score enum and the 16 bits
word extracting functions in a way that is 100% standard
compliant and with no speed regression on gcc and also on
the other compilers.
Verified it works on all compilers and with equivalent
functionality.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
The compiler is allowed to chose the size of an enum variable
based on the values it is expected to store. So force the compiler
to use at least a 32 bit integer type for the Score.
MSVC and Intel do not change, while gcc under -O3 is affected
by this change.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
We cannot cast a pointer type to an unrelated pointer type.
This is a violation of the strict aliasing rules.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
It is not clear why is not true, even in single thread
case, but as a matter of fact it is not!
So remove it.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Unfortunatly we need to slow down to -O1 to be sure
it works always.
Note that sometime it works also with -O2 or even -O3,
but user has to try himself.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
