Defining class inputs and outputs

[malcolm-dsider]

For the documentation, please define what values and arrays are passed between which class. For example, the array Tresoutput (reservoir temperature over time) is a key required output value for any reservoir model and is used in the Wellbores object. The wellbore parameters nprod and ninj are used in some of the Reservoir objects.

This ese relationships are important to know when defining new child objects.