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Reconstructing cellular automata rules from observations at nonconsecutive times

Cornell Affiliated Author(s)

Author

V. Elser

Abstract

Recent experiments have shown that a deep neural network can be trained to predict the action of t steps of Conway's Game of Life automaton given millions of examples of this action on random initial states. However, training was never completely successful for t>1, and even when successful, a reconstruction of the elementary rule (t=1) from t>1 data is not within the scope of what the neural network can deliver. We describe an alternative network-like method, based on constraint projections, where this is possible. From a single data item this method perfectly reconstructs not just the automaton rule but also the states in the time steps it did not see. For a unique reconstruction, the size of the initial state need only be large enough that it and the t-1 states it evolves into contain all possible automaton input patterns. We demonstrate the method on 1D binary cellular automata that take inputs from n adjacent cells. The unknown rules in our experiments are not restricted to simple rules derived from a few linear functions on the inputs (as in Game of Life), but include all 22n possible rules on n inputs. Our results extend to n=6, for which exhaustive rule-search is not feasible. By relaxing translational symmetry in space and also time, our method is attractive as a platform for the learning of binary data, since the discreteness of the variables does not pose the same challenge it does for gradient-based methods. © 2021 American Physical Society.

Date Published

Journal

Physical Review E

Volume

104

Issue

3

URL

https://www.scopus.com/inward/record.uri?eid=2-s2.0-85114696064&doi=10.1103%2fPhysRevE.104.034301&partnerID=40&md5=deac8b176c0933fbeeec765455b440fd

DOI

10.1103/PhysRevE.104.034301

Group (Lab)

Veit Elser Group

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