Vajolet

are UCI compliant open source chess engines by Marco Belli, written in C++ and released under the GNU General Public License v3. Vajolet, named after the [|Vajolet Towers] in the [|Dolomites], started its life in 2010 as C# engine. When Marco worked through Stef Luijten's tutorial on Winglet, //Writing a Chess Program in 99 Steps//, he rewrote Vajolet in C++. Vajolet 2.03 played the International Gsei Web Tournament 2013 and qualified for the final of 8 Italian and 8 non Italian engines, where it lost from iCE. || toc =Vajolet2= **Vajolet2**, first released in May 2014, was another complete rewrite in C++11. Apparently, Texel's Tuning Method worked well for Vajolet2.
 * Home * Engines * Vajolet**
 * [[image:320px-Torri_del_Vaiolet.JPG link="http://en.wikipedia.org/wiki/File:Torri_del_Vaiolet.JPG"]] ||~ || **Vajolet** and **Vajolet2**,
 * [|Vajolet Towers] ||~ ||^ ||

=Description=

Board Representation
Vajolet2 is a bitboard engine and used a kindergarten like technique taken from Winglet to determine sliding piece attacks with 32 [|KiB] precalculated lookup tables[64][64] each on ranks, files, diagonals and anti-diagonals, indexed by square and hashed line occupancy - the inner six bits multiplied by a magic factor and shifted right by the strange looking 57, while 58 is more natural to ensure a six bit index range, but factors are designed that the most significant bit of the 64-bit product will be clear. Since June 2016 with Vajolet2 2.2 sliding piece attacks are determined by Pradu Kannan's implementation of Magic Bitboards. Along with piece lists, Vajolet2 performs a staged legal move generation.

Search
The search uses C++ [|function templates] to distinguish between pure alpha-beta and PVS, for the main search as well for quiescence. Vajolet2 2.1, released in January 2016, applies Lazy SMP. The list of selectivity features is quite huge.

Selectivity

 * Check Extensions
 * Delta Pruning
 * Futility Pruning
 * History Leaf Pruning
 * Late Move Reductions
 * Late Move Pruning
 * Mate Distance Pruning
 * Mate Threat Extensions
 * Multi–ProbCut
 * Null Move Pruning
 * Quiescence Search
 * Razoring
 * Restricted Singular Extensions
 * SEE Pruning
 * Sibling Prediction Pruning
 * Static Null Move Pruning

Move Ordering

 * Principal Variation Extraction
 * Killer Heuristic
 * History Heuristic
 * Internal Iterative Deepening
 * MVV-LVA
 * Static Exchange Evaluation

Transposition Table

 * Zobrist Hashing
 * Four Bucket System
 * Depth-preferred Replacement Scheme

Evaluation

 * Material Balance
 * Mobility
 * Piece-Square Tables
 * Tapered Eval

Pawn Structure

 * Backward Pawn
 * Candidate Passed Pawn
 * Doubled Pawn
 * Isolated Pawn
 * Passed Pawn
 * Pawn Chain

King Safety

 * Pawn Shield
 * Pawn Storm
 * Square Control

Caches

 * Evaluation Cache
 * Material Cache
 * Pawn Cache

Misc
> and more ...
 * Center Control
 * Loose Pieces
 * Number of Pawn Rams as Blockage Indicator

=See also=
 * Geography

=Forum Posts=

2010 ...

 * [|Vajolet Chess Engine] by Marco Belli, CCC, May 27, 2010
 * [|Re: Test 071112] by Marco Belli, CCC, November 10, 2012
 * [|vajolet 2.03 release] by Marco Belli, CCC, May 12, 2013
 * [|vajolet 2.48 released] by Marco Belli, CCC, November 21, 2013
 * [|floating point SSE eval] by Marco Belli, CCC, December 13, 2013 » Evaluation, Float, Score
 * [|where can I make my engine play against human?] by Marco Belli, CCC, February 16, 2014
 * [|Vajolet2 released] by Marco Belli, CCC, March 29, 2014
 * [|vajolet2 1.43 released] by Marco Belli, CCC, July 22, 2014
 * [|advanced tapered evalutation] by Marco Belli, CCC, August 08, 2014 » SSE, Tapered Eval
 * [|vajolet2 1.45 release] by Marco Belli, CCC, August 15, 2014

2015 ...

 * [|Vajolet2 2.0 released] by Marco Belli, CCC, April 21, 2015
 * [|Vajolet 2.1 released] by Marco Belli, CCC, January 01, 2016
 * [|Vajolet, new version 2.2] by Marco Belli, CCC, June 19, 2016
 * [|vajolet2 2.3 release] by Marco Belli, CCC, February 28, 2017
 * [|Vajolet2 2.4 Release] by Marco Belli, CCC, November 19, 2017
 * [|Vajolet2 2.5 Release] by Marco Belli, CCC, January 25, 2018

=External Links=

Chess Engine

 * [|GitHub - elcabesa/vajolet]
 * [|vajolet chess engine - Google Project Hosting]
 * [|vajoletChess Blog]
 * [|Vajolet] « G 6
 * [|Vajolet] in CCRL 40/40
 * [|Vajolet] in CCRL 40/4

Misc

 * [|Vajolet Towers from Wikipedia]
 * [|Torri del Vajolet / Vajolet Towers : Climbing, Hiking & Mountaineering : SummitPost]
 * [|Vajolet Towers] by [|Dietrich Belitz], July 29, 2004
 * [|Rosengarten group from Wikipedia]

=References= =What links here?= include page="Vajolet" component="backlinks" limit="40"
 * Up one Level**