Given an initial distribution of sand in an Abelian sandpile, what final state does it relax to after all possible avalanches have taken place? In d ≥ 3, we show that this problem is P-complete, so that explicit simulation of the system is almost certainly necessary. We also show that the problem of determining whether a sandpile state is recurrent is P-complete in d ≥ 3, and briefly discuss the problem of constructing the identity. In d = 1, we give two algorithms for predicting the sandpile on a lattice of size n, both faster than explicit simulation: a serial one that runs in time C (n log n), and a parallel one that runs in time C (log3 n), i.e., the class NC3. The latter is based on a more general problem we call additive ranked generability. This leaves the two-dimensional case as an interesting open problem.
CITATION STYLE
Moore, C., & Nilsson, M. (1999). The computational complexity of sandpiles. Journal of Statistical Physics, 96(1–2), 205–224. https://doi.org/10.1023/a:1004524500416
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