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Eternity II

Go faster

Raw throughput: bit tricks, cache-friendly layouts, nodes-per-second engineering, and why speed alone cannot crack the puzzle.

Why it's hard

finding
Why a faster computer doesn't help

Build a solver

reference
The community's benchmarks
page
How the record solvers search
concept
Solver engineering: the craft below the algorithm
concept
Distributed solving: swarms, syndicates, and core farms
concept
GPU solving: the wall is memory, not arithmetic
concept
FPGA solving: mapped but never driven

The lab

experiment
Single-core benchmark
page
The reference engine behind this site
experiment
The JIT backtracker: portable Rust that ties hand-tuned C on hard boards
concept
Going fast: when a solver spends its budget on speed
page
The DFS study
page
How the study is built
page
What each idea buys
page
The repair study
page
How the study is built
page
What each decision buys
experiment
McGavin's C backtracker: the throughput story, built here
experiment
Blackwood's solver, decoded and run here
page
Verhaard's eii: the solver that won the only prize
experiment
Verhaard reimplementation

Neighbouring roads

All nine roads
Backtracking

DFS done seriously: fill orders, restarts, break indices.

Build boards up

Beam search, priors, staged assembly: compose, don't dig.