Figure 4.

The modules of OPS can be separated into different layers of abstraction. The layers can be considered as both increasing specificity of purpose (from bottom to top) as well as increasing ease of use or ease of implementation of new subclasses. Underneath the OPS modules are the external packages upon which OPS is built. Above that are OPS modules which have potential for use outside the context of reaction dynamics and path sampling. Above that the code becomes more specific to path sampling and to the OpenPathSampling project. At the top layer, some of the more powerful OPS libraries are abstracted into a more simple user interface. The level of user that is likely to spend significant time working at each level is indicated on the left.