When is the External Pathway Function Called?

The External pathway A transport pathway element that provides a mechanism by which external program modules for contaminant transport (e.g., analytical, finite elelement, or finite difference models) can be directly integrated into GoldSim. function is called at the following times:

• At the beginning of the simulation (Etime = 0);
• Every GoldSim timestep A discrete interval of time used in dynamic simulations.; and
• At any internal (unscheduled) timestep in which an Event is triggered

It is likely that you may want to treat each of these calls in a different way. For example, you may wish the External pathway function to ignore the call at the beginning of the simulation, or you may want it to carry out some special initialization routines at that time. You may also want to treat a call in the middle of a timestep (due to an Event) differently from a call at the end of a timestep. In order to communicate this kind of information to the External pathway function, you would need to send ETime (the current elapsed time) and perhaps TimestepLength (the length of the current timestep) to the External pathway function as optional input arguments.