Arasan 14.2

[jdart]

Arasan 14.2 is available from http://www.arasanchess.org.

Changes in Arasan 14.2:
1) The chess engine handled input from the the UI in several places
and had duplicate code for scanning input and breaking it into lines.
This is now centralized and simplifed.
2) Some other code cleanup, especially conversion from C-style string
handling to C++.
3) Simplified code for lazy eval. Partial (lazy) scores are no longer
cached in the scoring module (such scores were seldom used anyway).
4) Outpost scores reduced.
5) Tweaked threshold values for history pruning and late move pruning (due
to a bug, 14.1 actually did only late move pruning above depth =
1 ply).
6) Reduced thresholds for static null pruning.
7) Some changes to LMR and root move reduction logic.
8) Bug fix: ensure final stage of ply 0 search window widening sets a
correct upper/lower bound.
9) Improvement to logic for searching checks in q-search.
10) Fix material eval adjustment for Q vs 2R.
11) Support is added for varying the engine strength via UCI or Winboard
options (Arasan GUI supports this too).
12) GUI bug fix: search could hang when a "Go" command is issued when it
is the user's turn to move, and the user then makes a manual move before
the search completes.
13) Winboard driver fixes: pings could be processed out of order in some
cases. Also, an extra move could be sent after Winboard has sent a
"resign" or "result" command.

This version is measurably stronger than 14.1 in my testing.

I have also updated the test suite (arasan14.epd), replacing one position (arasan14.167) and adding some new ones (arasan14.176-197).

--Jon

[Jamal Bubker]

Thanks Jon !

[Graham Banks]

Arasan 14.2 is available from http://www.arasanchess.org.

Thanks Jon.

[Dan Honeycutt]

I have also updated the test suite (arasan14.epd), replacing one position (arasan14.167) and adding some new ones (arasan14.176-197).

--Jon

Hi Jon,

14.14 has a typo - it says "am Qxd6" should be "bm Qxd6".

Best
Dan H.

[jdart]

14.14 has a typo - it says "am Qxd6" should be "bm Qxd6".

Nope. "am" means "avoid move."

[d] 8/5pk1/3p1bp1/1B5p/2P1PP2/3Q2PK/5q2/8 w - - 0 1

Qxd6 here is bad: Black will reply .. h4, winning.

--Jon

[Dan Honeycutt]

14.14 has a typo - it says "am Qxd6" should be "bm Qxd6".

Nope. "am" means "avoid move."

Ahhh, thanks, I didn't know that.

Best
Dan H.

[fern]

In my comp. the change has been that Arasan does not do a thing. I play e4 and nothing happens....

What??'

Fern

[jdart]

I need a little more information. What plaform? What interface are you using? Is there a debug log available?

--Jon

[fern]

I use windows 7 and I use your GUI. As I said, after activating the exe, the board comes to life as usual, but then no move happens after the gui correctly display my first move.

Hope is enough for you to detect the issue.

my best
Fern, Arasan user since ever.

[jdart]

I will look into it.

It is not documented but if you start the GUI (arasan.exe) with "-trace" on the command line, it will produce a trace.log file. If you could do that it might be helpful.

--Jon