Restore old behaviour that after search is aborted we call insert_pv,
before breaking out from the iterative deepening loop.
Remove one useless FIXME and document other better.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Check all fail highs in assumed PV with greater care (fruit/Toga already does this).
Add a flag when aspiration search fails high at ply 1 to prevent search to
be terminated prematurely.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This reverts commit 55dd98f7c717b94a659931cd20e088334b1cf7a6.
Revert fallback-system for root_search
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
However also this patch is immediately reverted. For three reasons:
1) the case it affects is very rare (and then we are likely to lose anyway),
so we can well live without this.
2) Because the case is so rare it's hard to test this change properly.
3) To perform fallback search, we must reset so many global variables that this
patch is very likely both buggy and extremely bad style.
Consider including this again if we clean-up global variables one day...
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
However just after finished writing this patch I realized that this
is not the way to go. So this will be immediately reverted.
(Just save this here in git in case I change my mind later :) )
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Implement system where aspiration search window is calculated using
values from previous iterations.
And then some crazy experimental stuff: If search fails low at the root,
don't widen window, but continue and hope we will find a better move
with given window. If search fails high at the root, cut immediately,
add some more time and start new iteration.
Note: this patch is not complete implementation, but a first test
for this idea. There are many FIXMEs left around. Most importantly
how to deal with the situation when we don't have any move!
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Sometimes C++ can be really bad!
In this case an hard coded c string selects Option c'tor
with int argument instead of the std::string one becuase
it is considered a better matching by the compiler.
Fix the bug changing the argument type from std::string to
const char* so to be a better match then the int one.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Store boolean values as "1" and "0" instead of "true" and "false"
and convert back to UCI protocol convention when needed.
This is simpler then the other way around.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Apart from the teoretical speed increase, the main reason
of this patch is a good amount of code cleanup.
Note that now UCI options are printed in alphabetical
order and not in insertion order as before. Next patch
will take care of restoring old behaviour.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
In null move search do not jump directly in
qsearch() from depth(4*OnePly), but only
from depth(3*OnePly).
After 999 games at 1+0: +248 -224 =527 +8ELO
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
It doesn't seem to work against Toga. After more then 400 games
we are at -13 ELO while, without it we are at + 5 ELO after 1000
games.
So revert for now to keep code simple.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
MSVC gives:
warning C4146: unary minus operator applied to unsigned type,
result still unsigned
When finds -b where b is an unsigned integer. So rewrite the two's
complement in a way to avoid the warning. Theoretically the new
version is slower, but in practice changes nothing.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Strangely enough it seems that optimization doesn't work.
After 760 games at 1+0: +155 -184 =421 -13 ELO
Probably the overhead, although small, for setting the flag
is not compensated by the saved evaluation call.
This could be due to the fact that after a TT value is stored,
if and when we hit the position again the stored TT value is
actually used as a cut-off so that we don't need to go on
with another search and evaluation is avoided in any case.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
If we want to store a value of type VALUE_TYPE_EVAL for
a given position and we found an already exsisting entry
for the same position then we skip.
We don't want to overwrite a more valuable score with a
lesser one. Note that also in case the exsisting entry is
of VALUE_TYPE_EVAL type the overwrite is unuseful because
we would store the same score again.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
When the stored TT value equals the static value set a
proper flag so to not call evaluation() if we hit the
same position again but use the stored TT value instead.
This is another trick to avoid calling costly evaluation()
in qsearch.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Fix a bug in the way a move is stored and read in a TT entry.
We use a mask of 19 bits insteaad of 17 so that the last
two bits in the TT entry end up to be random data.
This bug will bite us when we will use these two until now
unused bits.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
After testing it seems patch is bad:
After 999 games 1+0: +242 -271 =486 -10 ELO
So restore saving of TT at the end but using new Joona
idea of storing as VALUE_TYPE_UPPER/VALUE_TYPE_LOWER instead
of VALUE_TYPE_EXACT.
Some optimization is still possible but better test new ideas
one by one.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Instead of just drop evaluation score after stand pat
logic save it in TT so to be reused if the same position
occurs again.
Note that we NEVER use the cached value apart to avoid an
evaluation call, in particulary we never return to caller
after a succesful tt hit.
To accomodate this a new value type VALUE_TYPE_EVAL has been
introduced so that ok_to_use_TT() always returns false.
With this patch we cut about 15% of total evaluation calls.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
It is now disabled by default due to bad results
against a pool of engines...more testing is needed tough.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This is the only "correct" exact value we can store.
Otherwise there could be spurious failed high/low nodes.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Some changes to the zobrist keys, to make them identical
to those used by Glaurung 1.
The only purpose is to make it possible for both programs
to use the same opening book.
Merged from Glaurung current development snapshot.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This is what prevented USE_32BIT_ATTACKS from working
on some architectures (like PowerPC).
Merged from Glaurung current development snapshot.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
We implicitly considered the minimum depth stored in TT
to be Depth(0), but because we store values in TT also in
qsearch() where depth is < 0, we need to use a negative
number as minimum depth.
Bug spotted by Joona Kiiski.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
I have just made a new rule that no modification
that increases pruning is allowed if after 1000 games
ELO is not increased by at least 10 point (was +5 in this case)
Yes, I like this kind of nosense rules :-)
Previous setup didn't change anything
After 996 games 1+0: +267 -261 =468 +2 ELO
Now with this new setup we have
After 999 games 1+0: +277 -245 =477 +11 ELO
Seems reasonable...
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Reduce of two plies near the leafs and when we still
have enough depth to go so to limit horizon effects.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
