“…A key advantage of using memristors in these computing paradigms is that only a few devices are required to fulfill the computing requirement, compared with potentially thousands using digital logic, promising a substantial reduction in materials and therefore great potential for higher-density circuits. 278 The past decade has witnessed great development of various types of artificial neural networks created by integrating memristors arrays, for convolutional neural networks, 195 spike neural networks, 279,280 recurrent neural networks, 281–283 deep neural networks, 193,284 and echo state neural networks. 285 These different neural networks have been used for a variety of applications such as pattern and face classification, 276,286,287 sparse coding, 288 multilayer perceptron network, 289 coincidence detection, 290 language learning, 291 reservoir computing, 256,292,293 reinforcement learning, 294 etc.…”