Fast Design Space Exploration of Nonlinear Systems: Part II

Nonlinear system design is often a multiobjective optimization problem involving the search for a design that satisfies a number of predefined constraints. The design space is typically very large since it includes all possible system architectures with different combinations of components composing each architecture. In this article, we address nonlinear system design space exploration through a two-step approach encapsulated in a framework called fast design space exploration of nonlinear systems (ASSENT). In the first step, we use a genetic algorithm to search for system architectures that allow discrete choices for component values or else only component values for a fixed architecture. This step yields a coarse design since the system may or may not meet the target specifications. In contrast to prior works on design space exploration that rely on forward design, we use an inverse design in step 2 to search over a continuous space and fine-tune the component values with the goal of improving the value of the objective function. We use a neural network (NN) to model the system response. The NN is converted into a mixed-integer linear program for active learning to sample component values efficiently. We illustrate the efficacy of ASSENT on problems ranging from nonlinear system design to the design of electrical circuits. Experimental results show that ASSENT achieves the same or better value of the objective function compared to various other optimization techniques for nonlinear system design by up to 53%. We improve sample efficiency by 6- 12 × compared to reinforcement learning-based synthesis of electrical circuits.