Peter McGavin

The 469 (2020); complex-theory C code

The long-decade anchor and, after Owen, arguably the puzzle's most consequential researcher. He computed the canonical figure of roughly 14,702 expected solutions, transcribed complex theory into LaTeX and then into exact C code that this site ports, and solved Owen's hint-free 10x10 in about 180 core-years, inside the theory's error bars. He held the record himself in 2020 with the 469.

Independent469 announcement (msg 10045)10x10 solve validating complex theory (msg 9686)

Experiments1 page

experiment

McGavin's C backtracker: the throughput story, built here

Peter McGavin's own C backtracker, the community's fastest: a 2007 optimization recipe compounded for two decades through generated code, lookup tables and counter tricks, then built on my M1 and pointed at the real 256-piece puzzle, where single core it drives past 200 of 256 pieces at ~109M placements/s.

Pages1 page

page

Peter McGavin's engine

Peter McGavin's own C backtracker, the fastest raw solver the community has measured. Fetched from the mailing list, built on an M1, and run on the real Eternity II. His code, his algorithm; run and written up here.