Circuit simulation has been a topic of great interest to the integrated
circuit design community for many years. It is a difficult, and
interesting, problem be- cause circuit simulators are very heavily used,
consuming thousands of computer hours every year, and therefore the
algorithms must be very efficient. In addi- tion, circuit simulators are
heavily relied upon, with millions of dollars being gambled on their
accuracy, and therefore the algorithms must be very robust. At the
University of California, Berkeley, a great deal of research has been
devoted to the study of both the numerical properties and the efficient
imple- mentation of circuit simulation algorithms. Research efforts have
led to several programs, starting with CANCER in the 1960's and the
enormously successful SPICE program in the early 1970's, to MOTIS-C,
SPLICE, and RELAX in the late 1970's, and finally to SPLICE2 and RELAX2
in the 1980's. Our primary goal in writing this book was to present some
of the results of our current research on the application of relaxation
algorithms to circuit simu- lation. As we began, we realized that a
large body of mathematical and exper- imental results had been amassed
over the past twenty years by graduate students, professors, and
industry researchers working on circuit simulation. It became a
secondary goal to try to find an organization of this mass of material
that was mathematically rigorous, had practical relevance, and still
retained the natural intuitive simplicity of the circuit simulation
subject.