Functional decomposition is the process of resolving a functional relationship into its constituent parts in such a way that the original function can be recomposed from those parts by functional composition. Perfect decomposition requires the obtained constituent parts to be non-interacting components and easier to conceive, understand, program, and maintain. However, how to decompose a complex system and ensure the correctness of such a decomposition approach usually relies on some informal principles. In this paper, we present a new and automatic decomposition approach for functionalities. We first show the correctness of the functional decomposition in terms of weakly termination in theory and then discuss the automation method of the functional decomposition. The approach can automatically decompose a system into independent subsystems which may be independently developed and deployed. Finally, we develop an algorithm. A case study demonstrates these results.

功能分解是将功能关系分解为其组成部分的过程，通过这种方式，原始功能可以通过功能组成从这些部分中重新组成。完美的分解要求所获得的组成部分是非交互的组件，并且更易于构思，理解，编程和维护。但是，如何分解复杂的系统并确保这种分解方法的正确性通常取决于一些非正式的原则。在本文中，我们提出了一种新的自动分解功能的方法。我们首先从弱终止的角度证明功能分解的正确性，然后讨论功能分解的自动化方法。该方法可以将系统自动分解为可以独立开发和部署的独立子系统。最后，我们开发了一种算法。案例研究证明了这些结果。