Coupled Simulation Methodology for In-Memory Computing Systems

Simulations for the development and optimization of future in-memory computing (IMC) systems often face the problem that the modeling of the large system is desired, but at the same time, the effects at the device level should also be taken into account. Such effects could be due to the material properties and geometries of the nanoscale structures, which are too time-consuming to model in a system-level (SL) simulation. For certain problems and applications, however, it is advantageous or even essential that a high-level model responds to the details of a low-level model. In this article, we present a coupled simulation methodology to overcome this challenge. In a case study, we show the integration of a material-level (ML) memristor simulation, serving as a vector-matrix multiplication (VMM) unit, into an SL simulation. The simulation process between two distributed simulators is controlled by a co-simulation interface (CSI), which we present here. With this co-simulation approach, devices and circuits can be optimized for their application, for example, with regard to energy efficiency. It can also be extended to a multilevel simulation flow.