Antonio Torrecillas wrote:
"Rocinante 2.0 is available at http://sites.google.com/site/barajandotrebejos/
Extracted from the readme.txt
Rocinante 2.0 is a cuasi complete rewrite of Rocinante.
There have been some refactoring and changes to optimize the
execution of the program without significantly altering the
The version 1.01 was bitboard and this new release uses mailbox.
Some code has been stolen from Simplex (Zobrist, hashtable, PVS etc).
A new algorithm has been added. MCTS_AB: Monte Carlo Tree Search alpha beta.
Monte Carlo programs are successful in the game of Go, but are notoriously
ineffective in chess. I intend to add this algorithm to verify the veracity
of these claims.
I've added a new evaluation function. And a SeeEval that replaces a quiesce search.
This is configured using UCI protocol options.
2. UCI Options.
id name Rocinante 2.0
id author Antonio Torrecillas
option name cpus type spin default 1 min 0 max 256
option name threads type spin default 1 min 0 max 256
option name klevel type spin default 1 min 0 max 1
option name mcts_ab type check default true
option name probedepth type spin default 1 min -1 max 10
Option cpus and threads control the number of worker threads.
Option mcts_ab control the main algorithm.
true -> use of mcts_ab Monte Carlo Tree Search
false -> use PB* Probability Based B star.
Option klevel control the evaluation function
0 -> UFO material + Piece square tables.
1 -> Material + development + PST + Mobility + ...
Both MCTS_AB and PB* have an alpha beta algorithm as a replacement
for a static evaluation. Probe Depth control the depth of this alpha beta.
-1 -> no alpha beta is used. Instead a static exchange evaluation is used.
0 -> quiesce evaluation. (MVLA).No checks.
1 -> one ply + quiesce.
2 -> two ply alpha beta + quiesce.
3 -> 3 plys AB+quiesce.
4 and up -> iterative deepening + LMR + nullmove etc.
Unfortunately I can't tell which parameter set is better for each time control. There is a hardcoded limit of 8000 expands.If this limit is reached, consider increasing the depth probe. A minimum of expanded nodes are needed for a correct work of the algorithm. (for PB* 112 expands).
Known bug: Multi procesor is broken in Linux platforms."