Optimisation Methods in SPICE, a Comparison

The field of optimisation is still not appropriately covered in modern computer programs for circuit analysis as SPICE. It was originally developed at the University of California at Berkeley. The last official release of SPICE 3f4 was published in 1992. It has numerous bugs, mainly memory leaks. In order to implement optimisation methods most bugs were tracked down and fixed. Several well-known optimisation methods were implemented. The new command optimize was added to the interactive command interpreter called Nutmeg to manipulate with optimisation tasks. The optimize command represents a general optimisation tool, which can be used on any circuit with arbitrary cost function. The syntax of the command is introduced in the paper. Further five test circuits were optimised with different methods and a comparison between the implemented methods is presented. The essential properties of the optimisation methods in real optimisation problems are shown. All simulation files as well as the new compilation of SPICE may be downloaded from http://fides.fe.unilj.si/spice/.