On Implementation and Extension Complexities

Summary

A software system may be considered as an implementation of a number of different algorithms. An evaluation of the time and space complexities of all the algorithms of the system may be employed to detect possible performance problems. There are, however, situations where the costs of computations are acceptable, but the costs of implementation and of later extensions of the system are unacceptably high. In order to check whether a given algorithm may involve such implementation or extension costs, the concepts of implementation complexity and extension complexity were introduced in [Kant97]. The implementation and extension complexities of a given algorithm may usually be estimated in a few minutes. The implementation and extension complexities may therefore be employed together with the time and space complexities for detecting and avoiding problematic algorithms. This paper starts with the definition of the concepts, and then gives some examples.