Floyd

Home * Engines * Floyd

[.jpg) Hurricane Floyd [1] Floyd,

an UCI compliant open source chess engine for study purposes and prototyping of new ideas by Marcel van Kervinck, written in C, and first released in October 2015 [2] with a permissive license [3] . Floyd can be build to run under Windows, Linux and Mac OS. Floyd had its over the board tournament debut at the IGT 2016 with a 50% score.

Description#

Board Representation#

Floyd uses an 8x8 Board, agnostic to square indexing, in the sense that it can be adapted to any of the eight possible board geometries with just a local change [4] . It uses an attack table, for each side an array of 64 bytes, with following one- or two-bit attack counters per square …

+-----+-----+-----+-----+-----+-----+-----+-----+
|   Pawns   |   Minors  |   Rooks   |Queen|King |
+-----+-----+-----+-----+-----+-----+-----+-----+
     7..6        5..4        3..2      1     0

… as used in move generation, SEE and evaluation.

Search#

The search is a classical PVS iterative deepening approach with Zobrist key transposition table, quiescence search, null move pruning and mate distance pruning. Move ordering considers SEE and a simple killer heuristic.

Evaluation#

Floyd’s evaluation employs a vector of feature and weight pairs to calculate a score as weighted sum. In conjunction with a draw model [5] using sigmoid functions, the score is mapped to winning probabilities, suited for logistic regression tuning.

def evaluate(board, wiloVector, drawVector):
        wiloScore = ...snip... // a weighted sum of board features
        drawScore = ...snip... // another weighted sum of board features

        return sigmoid(drawScore) * 0.5
             + sigmoid(wiloScore)
             - sigmoid(wiloScore) * sigmoid(drawScore)

Misc#

Floyd provides a Python API for search and evaluation functions [6] , i.e. for automated tuning [7] . It generates a compact KPK tablebase to deal with perfect knowledge, also available as stand alone project [8] [9] .

See also#

• Mathematician - Robert W. Floyd (1936 - 2001)
• MSCP
• Rookie

Forum Posts#

• Floyd 0.5 released by Marcel van Kervinck, CCC, October 11, 2015
• Floyd 0.6 released by Marcel van Kervinck, CCC, October 17, 2015
• Floyd 0.7 released by Marcel van Kervinck, CCC, November 15, 2015
• Floyd 0.8 released by Marcel van Kervinck, CCC, March 31, 2016
• Floyd 0.9 released by Marcel van Kervinck, OpenChess Forum, August 20, 2016

External Links#

Chess Engine#

• kervinck/floyd · GitHub
• Download page - Floyd chess engine - /etc/marcelk
• Floyd 0.6 64-bit in CCRL 40/4

Misc#

• Floyd from Wikipedia
• Hurricane Floyd from Wikipedia
• Robert W. Floyd from Wikipedia
• Floyd’s cycle-finding algorithm from Wikipedia
• Floyd–Hoare logic from Wikipedia
• Floyd–Steinberg dithering from Wikipedia
• Floyd–Warshall algorithm from Wikipedia
• Pink Floyd - High Hopes, The Division Bell, 1994, YouTube Video

References#

1. ↑ Hurricane Floyd near peak intensity on September 14, 1999 at 2030 UTC. This image was produced from data from NOAA-14, provided by NOAA, Wikimedia Commons, Hurricane Floyd from Wikipedia
2. ↑ Floyd 0.5 released by Marcel van Kervinck, CCC, October 11, 2015
3. ↑ floyd/LICENSE at master · kervinck/floyd · GitHub
4. ↑ floyd/geometry.h at master · kervinck/floyd · GitHub
5. ↑ floyd/drawModel.txt at master · kervinck/floyd · GitHub
6. ↑ floyd/README.md at master · kervinck/floyd · GitHub
7. ↑ floyd/tune.py at master · kervinck/floyd · GitHub
8. ↑ Yet another KPK endgame table generator: pfkpk by Marcel van Kervinck, CCC, September 05, 2015
9. ↑ kervinck/pfkpk · GitHub

Up one Level