Algorithms for ASTAP--A Network-Analysis Program

The advanced statistical analysis program (ASTAP) is a general-purpose network-analysis program which performs nonlinear transient, dc, and ac analyses and provides statistical simulation to determine the distribution of circuit outputs due to parameter variations. The program combines a user-oriented input language capable of describing completely general nonlinear devices with the latest advances in numerical and programming techniques: variable-order implicit integration, tableau formulation, and sparse-matrix solution methods. This paper describes how these techniques have been implemented in the ASTAP program. Attention is focused on the computational algorithms.