Symbolic circuit analysis suffers from the exponential growth of expression
complexity with circuit size. Therefore, either if the symbolic expressions are used for
gaining insight into circuit operation or for repetitive computer-based evaluations,
simplification becomes mandatory. This chapter reviews the different existing
techniques for symbolic expression simplification, classifying them into three categories
according to the step at which the simplification is performed: on the circuit equations,
during the solution of the circuit equations or after the circuit equations have been
solved. Pros and cons of each approach are discussed.
Keywords: Approximated symbolic analysis, approximation techniques, simplification before
generation, graph reduction, matrix reduction, simplification after generation, simplification during
generation, approximation error, symbolic term generation, two-graph method, matroid intersection,
determinant decision diagram.
