A geometric program (GP) is a type of mathematical optimization problem
characterized by objective and constraint functions that have a special form. Recently
developed solution methods can solve even large-scale GPs extremely efficiently and
reliably; at the same time a number of practical problems, particularly in circuit de-
sign, have been found to be equivalent to (or well approximated by) GPs. Putting
these two together, we get effective solutions for the practical problems. The basic
approach in GP modeling is to attempt to express a practical problem, such as an en-
gineering analysis or design problem, in GP format. In the best case, this formulation
is exact; when this is not possible, we settle for an approximate formulation. This
tutorial paper collects together in one place the basic background material needed
to do GP modeling. We start with the basic definitions and facts, and some methods
used to transform problems into GP format. We show how to recognize functions and
problems compatible with GP, and how to approximate functions or data in a form
compatible with GP (when this is possible). We give some simple and representative
examples, and also describe some common extensions of GP, along with methods for
solving (or approximately solving) them.
