Taking Advantage of Existing Files

Often, you will make multiple time-domain simulation runs on the same system. After the first simulation run is finished, the Switching Instance Data file mentioned in Switching Instance Data File and the Topology Information file outlined above are created. After examining the waveforms from this simulation run, you may decide to either repeat the simulation with a longer run time or repeat the same simulation run with a different set of print variables. In either case, there is no change in the system under study and the Switching Instance Data file and the Topology Information file contain valuable information associated with the time-domain simulation. In the next simulation run, SIMPLIS can take advantage of the data stored in these two files and reduce the computation time in the simulation.

Every time SIMPLIS is invoked, it looks for the presence of the Topology Information file, the "XXXX.tc" file. If this file is present and the circuit it describes matches that of the input file, SIMPLIS can take advantage of the existing knowledge on the different circuit topologies and the overhead spent in analyzing each known circuit topology is reduced.

As outlined in Overview, SIMPLIS is a two-pass simulator when it comes to time-domain simulation. The first pass of the simulation is the regular simulation and it computes the state of the simulation at each switching instance and saves the data in the Switching Instance Data file -- the "XXXX.t1" file. In the second pass, called the Post-Simulation Processing, or "PSP" for short, detailed waveform data are reconstructed from the data saved in the Switching Instance Data file. Every time SIMPLIS starts a time-domain analysis, it looks for the presence of the Switching Instance Data file. If this file is present, SIMPLIS checks to see if it is usable. This file is considered usable if it describes the same circuit and the same analyses as defined in the input file. If the Switching Instance Data file is considered usable, SIMPLIS can skip the first pass of the simulation and directly go to the Post-Simulation Processing phase, saving a substantial amount of simulation time. Changing the PSP_START, PSP_END, and PSP_NPT parameters through the option statements is not considered to be a change in the analyses as these parameters only affect the PSP-phase of the simulation.

Since the Topology Information file and the Switching Instance Data file contain critical data of the simulation, they have been created with a read-only protection mode to prevent accidental changes being made to them.