We study a class of Hopfield models where the memories are represented by a mixture of Gaussian and binary variables and the neurons are Ising spins. We study the properties of this family of models as the relative weight of the two kinds of variables in the patterns varies. We quantitatively determine how the retrieval phase squeezes towards zero as the memory patterns contain a larger fraction of mismatched variables. As the memory is purely Gaussian retrieval is lost for any positive storage capacity. It is shown that this comes about because of the spherical symmetry of the free energy in the Gaussian case. Introducing two different memory pattern overlaps between spin configurations and each contribution to the pattern from the two kinds of variables one can observe that the Gaussian parts of the patterns act as a noise, making retrieval more difficult. The basins of attraction of the states, the accuracy of the retrieval and the storage capacity are studied by means of Monte Carlo numerical simulations. We uncover that even in the limit where the network capacity shrinks to zero, the (few) retrieval states maintain a large basin of attraction and large overlaps with the mismatched patterns. So the network can be used for retrieval, but with a very small capacity.
A Hardware-aware Hopfield Network with a Nonlinear Memristor Array for Robust Associative Memory with Superlinear Capacity
Korea Institute of Science and Technology (KIST)(韩国科学技术院);Korea Advanced Institute of Science and Technology (KAIST)(韩国科学技术院);Seoul National University(首尔大学);Korea University(韩国大学);KIST School, University of Science and Technology(韩国科学技术院科学技术研究生院)
John A. Paulson School of Engineering and Applied Sciences(约翰·A·保尔森工程与应用科学学院);Center for Brain Science(脑科学中心);Department of Physics(物理系);MIT-IBM Watson AI Lab, IBM Research(MIT-IBM沃森人工智能实验室,IBM研究院);Kempner Institute for the Study of Natural and Artificial Intelligence(肯普纳自然与人工智能研究所)
Kempner Institute for the Study of Natural and Artificial Intelligence, Harvard University(哈佛学院肯普纳自然与人工智能研究所);Zuckerman Institute, Columbia University(哥伦比亚大学祖克曼研究所);Kavli Institute for Brain Science, Columbia University(哥伦比亚大学卡弗里脑科学研究所)
Serial vs parallel recall in the Blume-Every-Griffiths neural networks
Istituto Nazionale di Alta Matematica Francesco Severi(意大利高等数学研究所弗朗切斯科·塞韦里);Università del Salento(萨伦托大学);Dipartimento di Matematica e Fisica, Università del Salento(萨伦托大学数学与物理系);Istituto Nazionale di Fisica Nucleare, Sezione di Lecce(意大利国家核物理研究院莱切分部);Dipartimento di Informatica, Università di Pisa(比萨大学计算机科学系);Sapienza Università di Roma(罗马智慧大学);Dipartimento di Scienze di Base e Applicazioni all’Ingegneria, Sapienza Università di Roma(罗马智慧大学基础科学与工程应用科学系);Istituto Nazionale di Fisica Nucleare, Sezione di Roma(意大利国家核物理研究院罗马分部);CNR Nanotec, Sezione di Lecce(意大利国家研究委员会纳米技术研究所莱切分部)
Exponential Capacity in Multilayer Hetero-Associative Neural Networks
Dipartimento di Matematica, Sapienza Università di Roma(罗马大学数学系);Istituto Nazionale d’Alta Matematica, GNFM(高等数学国立研究所);CNR-Nanotec, Unità di Lecce(意大利国家研究委员会纳米技术研究所莱切分部);Dipartimento di Scienze di Base e Applicate all’Ingegneria, Sapienza Università di Roma(罗马大学基础与应用工程科学系);Istituto Nazionale di Fisica Nucleare, Sezione di Roma 1(意大利国家核物理研究所罗马第一分部)