Tidy up comments in thread.cpp

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Tidy up comments in uci.cpp

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Don't disable IO buffering at startup

It was never clear to me why we needed this trick, and now
that we rely only on C++ std::getline() and std::cout for
input / output it is even more a mistery what this code does.

So disable it and wait to see if someone screams ;-)

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Retire neighboring_files_bb() overload

Rarely used and we prefer to not hide the complexity.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Prefer 0 to EmptyBoardBB

Easier and even faster or at least easier to optimize.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Retire move.h

Also some assorted comments fixes and other trivia.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Move SearchStack under Search namespace

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Fix disambiguation bug in move_to_san()

A pinned piece cannot move and so does not play any role
in SAN disambiguation.

Reported by Steven Edwards.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Use operator() instead of apply() in endgames

It is more idiomatic for a functor (a function object) as are
the endgames.

Suggested by Rein Halbersma.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Prefer empty() to size()

As Heinz says:

"Function empty() should have a constant run-time even
 on lousy compilers and you spare the not.

The change is even measurable: + 100-150 nodes/sec. Wow:-)"

Patch from Heinz van Saanen

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Retire all extensions (but checks) for non-PV nodes

It seems we don't have any added value. Note that the
moves that were used to be extended are still flagged
as dangerous so to avoid at least pruning them.

After 9555 games
Mod vs Orig 1562 - 1540 - 6453 ELO +0 (+- 4)

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Remove some (int) casts

A cast rarely is the right solution. In this case was enough
to redifine 3 variables with type size_t instead of int

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Set captureThreshold according to static evaluation

Consider negative captures as good if
still enough to reach beta.

After 7502 games:
Mod vs Orig 1225 - 1158 - 5119 ELO +3 (+- 4.5)

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Fix compile for 64 bits

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Fix description of endgame scaling functions

Triggered by a comment of Eelco on talkchess. Also
a bit of cleanup while there.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Don't update bestValue when pruning

Simply return a fail-low score

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Allow to prune also first move

Tested togheter with previous patch; shows no regression and
is a semplification.

After 5817 games:
Mod vs Orig 939 - 892 - 3986 ELO +2 (+- 5.1)

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Prune silly comments in search()

Comments should be informative but not pedantic / obvious.
The only exception is the function description where we
indulge a bit on the "chatty" side, but has always been like
this since Glaurung times, so we continue with this tradition.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Fix a crash when quitting while searching

The Position object used by UI thread is a local variable in
uci_loop(), so after receiving "quit" command the function
returns and the position is freed from the stack.

This should not be a problem becuase in start_thinking() we copy
the position to RootPosition that is the one used by main search
thread. Unfortunatly we blindly copy also StateInfo pointer that
still points to the startState struct inside UI position. So the
pointer becomes stale as soon as UI thread leaves uci_loop() and
because this happens while main search thread is still recovering
after the 'stop' signal we have a crash.

The fix is to update the pointer to the correct startState after
the copy.

Found with Valgrind.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Fix another crash triggered by previous patch

It is ok to redirect st pointer to startState, but the latter
should be updated with the content pointed by the st of the
original position. The bug is hidden when startState and *st
are the same as is the case of searching from start position,
but as soon as moves are made (as is the case when splitting)
the bug leads to a crash.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>