1. A simulator comprising: a processing module; and a memory, the processing module being configured as or controlling an analysis module for extracting a state-space model of response of a physical system to an input from a frequency-domain representation of the response, using a singular-value decomposition (SVD) and singular vectors of a Loewner matrix derived by the analysis module from the frequency-domain representation; and the processing module being configured as or controlling a simulator module for simulating the response of the physical system in a time domain based on the extracted state-space model.