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Combinatorial optimization by weight annealing in memristive hopfield networks

Authors :
Zahra Fahimi
Mohammad Reza Mahmoodi
Valentin Polishchuk
Hussein Nili
Dmitri B. Strukov
Source :
Scientific Reports, Scientific Reports, Vol 11, Iss 1, Pp 1-10 (2021)
Publication Year :
2021
Publisher :
Springer Science and Business Media LLC, 2021.

Abstract

The increasing utility of specialized circuits and growing applications of optimization call for the development of efficient hardware accelerator for solving optimization problems. Hopfield neural network is a promising approach for solving combinatorial optimization problems due to the recent demonstrations of efficient mixed-signal implementation based on emerging non-volatile memory devices. Such mixed-signal accelerators also enable very efficient implementation of various annealing techniques, which are essential for finding optimal solutions. Here we propose a "weight annealing" approach, whose main idea is to ease convergence to the global minima by keeping the network close to its ground state. This is achieved by initially setting all synaptic weights to zero, thus ensuring a quick transition of the Hopfield network to its trivial global minima state and then gradually introducing weights during the annealing process. The extensive numerical simulations show that our approach leads to a better, on average, solutions for several representative combinatorial problems compared to prior Hopfield neural network solvers with chaotic or stochastic annealing. As a proof of concept, a 13-node graph partitioning problem and a 7-node maximum-weight independent set problem are solved experimentally using mixed-signal circuits based on, correspondingly, a 20 x 20 analog-grade TiO2 memristive crossbar and a 12 x 10 eFlash memory array. Funding Agencies|Semiconductor Research Corporation (SRC) funded JUMP CRISP center, NSF/SRC E2CDA grant [1740352]; DENSO CORPORATION

Details

ISSN :
20452322
Volume :
11
Database :
OpenAIRE
Journal :
Scientific Reports
Accession number :
edsair.doi.dedup.....af820e2f6f7154be57d1a5a1c3706ebb
Full Text :
https://doi.org/10.1038/s41598-020-78944-5