Exhaustive search

SpinGlassPEPS.jl includes CPU and CUDA brute-force routines for small Ising models. The GPU routines enumerate every state, so their memory and runtime requirements grow exponentially with the number of spins.

Use brute_force for the CPU implementation. When CUDA.functional() is true, exhaustive_search returns the full energy ordering and exhaustive_search_bucket retains only the requested number of low-energy states.

References

1. Jałowiecki, K., Rams, M. M., & Gardas, B. (2021). Brute-forcing spin-glass problems with CUDA. Computer Physics Communications, 260, 107728.
2. Tao, M. et al. (2020). A Work-Time Optimal Parallel Exhaustive Search Algorithm for the QUBO and the Ising model, with GPU implementation. IPDPSW.
3. Cook, C. et al. (2018). GPU based parallel Ising computing for combinatorial optimization problems in VLSI physical design. arXiv:1807.10750.