The Selective-tracing Waveform Relaxation (STWR) algorithm, which combines good properties of traditional relaxation-based algorithms including Waveform Relaxation (WR) and Iterated Timing Analysis (ITA), has been discussed. STWR is basically a WR algorithm, but it selectively traces and schedules subcircuits for each subcircuit calculation. STWR is able to exploit circuits' multi-rate behaviors, uses dynamical windows (controlled by the convergence situations), and spends fewer number of subcircuit calculations in most test circuits. A new global feedback loop controlling method for STWR is proposed in this paper to reinforce the robustness of STWR. Properties of proposed methods have been tested by real experiments.
