Parallel circuit simulation with adaptively controlled projective integration

In this article, a parallel transient circuit simulation approach based on an adaptively-controlled time-stepping scheme is proposed. Different from the widely-used implicit numerical integration techniques in most transient simulators, this work exploits the recently-developed explicit telescopic projective numerical integration method for efficient parallel circuit simulation. Because telescopic projective integration addresses the well-known stability issue of explicit numerical integrations by adopting combinations of inner integrators and outer integrators in a multilevel fashion, the simulation time-step is no longer limited by the smallest time constant in the circuit. With dynamic control of telescopic projective integration, the proposed projective integration framework not only leads to noticeable efficiency improvement in circuit simulation, it also lends itself to straightforward parallelization due to its explicit nature. The latter has led to encouraging runtime efficiencies, observed on shared-memory parallel platforms. In addition to solving standard initial-value problems (IVPs) of differential equations, the same telescopic integration framework is adopted for solving final-value problems (FVPs), where the system is integrated backwards in time. Through a new elegant formulation, we show how an IVP and FVP can be simultaneously solved to allow for a coarse-grained bidirectional parallel circuit simulation scheme. Such a bidirectional approach is demonstrated in the context of parallel shooting-Newton-based steady-state circuit analysis. The proposed bidirectional approach has unique and favorable properties: the solutions of the two ODE problems are completely data-independent with built-in automatic load balancing.