Abstract
MINISIM is a general-purpose interactive digital simulation program which is written in FORTRAN and is suitable for both interactive and batch use. The program currently utilizes a fixed-step 4th-order Runge-Kutta integration algorithm. The program has proved to be suitable as a replacement for an analog computer in both teaching and research activities. OPTSIM is an extension of MINISIM that permits optimizing simulated systems automatically while making use of the MINISIM integration routines. The same problem-description subroutine (SUBROUTINE EQUATN) may be used with either MINISIM or OPTSIM. Detailed examples are given of the simulation and optimization of a control system and also of the solution of a two-point boundary-value optimization problem.