Almost no change so commit because is a pruning
reduction patch.
After 1088 games at 1'+0 with QUAD
Mod vs Orig +178 =727 -183 (-2 ELO)
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
We don't need to pass side_to_move because we can get
it directly from the position object.
Note that in benchmark we always used to pass '0' and
it was a bug, but with no effect because was used only
in time[] and increment[], set always to 0 for both
colors.
Also additional small cleanup while there.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Considering only VALUE_TYPE_EXACT nodes is too
restrictive and has a number of side-effects, most
notably the truncation of PV line after a fail high
at root.
Note that in this way we are no more guaranteed that
PV line is built up with PV nodes only, because
it could happen that a side search overwrites with a
cut-off move a PV node and this cut-off move ends up
in PV.
Change should be almost not measurable, perhaps with
ponder on we could have some beneficial effect.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Currently starting from depth 12*OnePly on we have a verification
search deeper then the null search.
Note that, although reduction is R we start from one ply less then
null search, so actually we reach a depth that is OnePly shallower
then null search.
After 1130 games at 1'+0 on QUAD
Mod vs Orig +202 =756 -172 +9 ELO
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
After the previous patch, it's impossible to build
anything else than x86 32-bit binary!
So revert.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Tested with Orig set at f5ef5632f so to evaluate
direct gain against 1.8
After 3239 games at 10"+0.1
Mod vs Orig +701 =1906 -632 +7 ELO
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Unfortunatly the source of this issue is not in the
different handling of log(0) illegal value.
No functional change on MSVC.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
It happens that when d == 0 we calculate:
log(double(0 * 0) / 2)
Unfortunately, log(0) is "illegal" and can generate either a
floating point exception or return a nonsense "huge" value
depending on the platform.
This fixs in the proper way the GCC/ICC rounding difference,
bug was from our side, not in the intel compiler.
Also fixed some few other warnings.
Bug spotted by Richard Lloyd.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Also renamed history access value in something more
in line with the meaning.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
It seems there is absolutely no difference in using gains.
After 7025 games at 5"+0
Mod vs Orig +1903 =3236 -1886 (+1 ELO)
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This time with a new algorithm by Joona.
It works basically like this:
repeat
{
1) pick 8000 random positions from qsearch
2) "go depth 8" to get the true evaluation.
3) "eval" to get the stand pat score
4) Adjusting parameters one by one to minimize deltasum between
true evaluation and stand pat scores.
}
* Good news: method seems to converge
* Bad news: Point where it converges is not optimum.
So it's more or less trial and error... sometimes works, sometimes
doesn't. It can give you the right direction, but if you let it run
too long, it fails. Far from scientific ;)
After 14800 games with 5s/game
Orig - Mod: 3318 - 3570 - 7626 (+6 elo)
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
When first condition is met then second one is
always true.
Spotted by Ralph Stoesser.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This should allow to skip overwritten nodes because
only in PV we store in TT with VALUE_TYPE_EXACT flag.
Test result for the whole series is:
After 3627 games at 5"
Mod vs Orig +1037 =1605 -985 +5 ELO
After 1311 games at 1'+0"
Mod vs Orig +234 =850 -227 +2 ELO
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Extract PV info from TT instead of using
a set of arrays. This is almost equivalent
except for cases when TT is full and the PV entry
is overwritten, but this is very rare.
(Almost) No functional change
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Due to rounding errors in apply_weight() where we divide
by 0x100 it is not possible to keep some functionality.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
A pawn is unstoppable also if enemy king can reach it
but path to queening is protected.
Original idea by Ralph Stoesser fixed by me.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
