MultiROW within Pstar A Feasibility Study

Multirate ideas for numerical time integration are explained concerning multirated extrapolation and stepsizing. Later parts of the report focus on Rosenbrock-Wanner (ROW) schemes, since those seemed to be most promising for the needs in circuit simulation: The ROW formula applicable to circuit di erential algebraic equations are introduced and changes within the analog circuit simulator Pstar are discussed. Furthermore, some aspects for re nement of the formulae to match Pstars needs are given. This project was a co-operation between Philips Research Eindhoven (Dept. ED&T/AS) and the Technische Universitat Darmstadt. It was executed at the Philips Nat.Lab. Eindhoven under supervision of Jan ter Maten (Philips Electronic Design & Tools, Analogue Simulation), Wil Schilders, (Philips Research, VLSI Design Automation and Test) and Michael G unther (Technische Universitat Darmstadt). Conclusions: Further numerical research is needed, to tailor the method to Pstar. The sweeping through the hierarchical structure is time consuming. Hence stages of a Runge-Kutta based scheme should be optimized with the evaluation costs of the elements, devices etc. Anyway, a new Runge-Kutta typed method requires fundamental changes within Pstar. Storage, stamping and Newton need to be adapted. c Philips Electronics N.V. 1998 iii 824/98 UNCLASSIFIED NATLAB REPORT iv c Philips Electronics N.V. 1998