23–26 May 2012
Ferry Stockholm-Mariehamn and Hotel Arkipelag, Mariehamn, Åland
Europe/Stockholm timezone

Analog approaches to hard optimization: from Sudoku to CNNs

25 May 2012, 10:45
45m
Ferry Stockholm-Mariehamn and Hotel Arkipelag, Mariehamn, Åland

Ferry Stockholm-Mariehamn and Hotel Arkipelag, Mariehamn, Åland

Speaker

Prof. Maria Magdolna Ercsey Ravasz (Babes-Bolyai University)

Description

The analog dynamical system we recently designed to solve constraint satisfaction (Nature Physics 7, 966, 2011) opens potential new avenues to handle hard optimization problems. As an example I will present our Sudoku solver and show how it helps us define a type of "Richter scale" to characterize the hardness of Sudoku problems. These analog solvers are based on the one-to-one correspondence between the solutions of a problem and the stable fixed-points of the dynamical system. However, the question arises how can we identify unsatisfiable formulas. Here I will present some new directions for handling the MAX-k-SAT problem. Due to the chaotic dynamics appearing in these solvers for hard problems, these systems become costly to simulate on Turing machines. Thus, it would be desirable to design real physical, continuous time systems or devices that share the same dynamics as these analog solvers. To facilitate physical implementations we developed a new dynamical model similar to Cellular Neural Networks which can solve k-SAT without getting trapped in non-solution fixed points and which can be implemented by analog circuits.

The work was done together with Prof. Zoltan Toroczkai, and my graduate student Botond Molnar.

Primary author

Prof. Maria Magdolna Ercsey Ravasz (Babes-Bolyai University)

Presentation materials

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