PL/SQL Chess Engine v0.92 (download the much stronger Release 1.01 under 'release')

This freeware chess engine, written in PL/SQL by Egon Von Bech Madsen for Oracle Database, consists of the following packages:

• PL_PIG_CHESS_ENGINE
• PL_PIG_CHESS_ENGINE_EVAL
• PL_PIG_CHESS_DATA
• PL_PIG_CHESS_INTERFACE

Technical Overview

PL/SQL

PL/SQL is a quite restricted and slow language to use for a Chess Engine. If You want top strength, don't use PL-PIG-Chess. Engines like StockFish (C language) is able to calculate around 100 times faster.

Fair Performance is reached by intensive use of VARRAYS, SIMPLE_INTEGER and INLINEable SET operators. And by NOT using SQL features. The many initiations of arrays happens only one time pr session/game.

Chess Engine

• Opening books (internal plus polyglot books)
• Static evaluation
• quiescence deepening minimax algorithm with alpha/beta cut-off and sort for better pruning
• Q-search deepening (deeper selective search on killer-moves like check, attacks, promotion, double-threats and pinning themes)
• Leaf (dynamic) evaluation
• Single CPU only
• Supports 5 levels (from few seconds to several minutes pr move).
• Rating: up to 1600 ( v1.0 up to 1900)
• PGN, FEN, EPD and Polyglot open chess formats is supported.
• All code is original and made from the bottom, mostly based on widespread ideas though.
• Automated test-suite to tune weights and features for best rating (the most time-consuming and critical part of coding an engine)

INSTALLATION

Install the 4 packages on a Oracle database:

1. PL_PIG_CHESS_ENGINE
2. PL_PIG_CHESS_ENGINE_EVAL
3. PL_PIG_CHESS_DATA
4. PL_PIG_CHESS_INTERFACE

USE:

1. Use SQL*PLUS or Toad/SQL-Developer with DBMS_OUTPUT activated
2. Use examples seen in PL_PIG_CHESS_INTERFACE

OR install the GUI PL_PIG_CHS_GUI or maybe make your own graphical (APEX?) interface...

License

This is distributed under the Diceware License.