The Xoshiro+ pseudorandom number generator in a computer chess program

Abstract

Since computer chess programs can beat human capabilities, new ways are researched to further improve these programs. Pseudorandom number generators (PRNG) play an important role in computer chess. We implement Xoshiro+, a well-known and thoroughly tested PRNG, in Stockfish, the arguably most performant chess engine at the time. Stockfish itself uses Xorshift*. With the help of Cute Chess, a program allowing the automation of chess games, the new Stockfish variant Xoshirofish is tested against Stockfish. The results show a minute increase in the performance of Xoshirofish compared to Stockfish. However, further extensive testing is still required to assert the significance of this increase in performance.