ESACAP™ from StanSim Research is a simulation program for non-linear dynamic systems. The first version was developed for the European Space Agency in 1979 by Paul Stangerup, now managing director of StanSim Research, and Stig Skelboe, now Professor in computer science at the University of Copenhagen. The contract undertaken by the Danish company ElektronikCentralen was a result of a strong need for an interdisciplinary simulation tool. Typically, one problem was to analyze an electronic system in a thermal environment. Therefore, the description language of ESACAP is very powerful as it was actually born with facilities that only much later became known as behavioral modelling.
ESACAP carries out DC analyses using a combined gradient-Newton method. Time domain analysis is implemented as backward differentiation with variable step and order. In the time domain, a possible periodic steady state solution is accelerated by an extrapolation method: the Epsilon algorithm. Stig Skelboe received the IEEE best paper award in 1980 for a paper about this algorithm. ESACAP also carries out frequency-domain analyses on linear or linearized systems and provides transfer functions vs. frequency as well as group delay and poles/zeros. Sensitivities (exact derivatives) with respect to any describing parameter is available in all analysis modes.
ESACAP is available on the following platforms: Windows NT/2000/XP, HP-UX, Sun Solaris, Linux