1. A computer-implemented method, comprising: obtaining, by a computer processor, electric field data corresponding to settings of an implanted leadwire that is adapted for stimulating anatomical tissue, the electric field data including for each of a plurality of neural elements a respective plurality of electric values for a same electric field parameter; determining in a first determining step, by the processor and for each of the neural elements, a respective activation status based on the respective plurality of electric values associated with the respective neural element; and the processor determining in a second determining step, and outputting an indication of, an estimated activated tissue region corresponding to a combination of points surrounding the leadwire corresponding to those of the neural elements for which an active status is determined; wherein the determining of the second determining step is performed by executing a first module that at least one of: does not base the determining of the second determining step on input of different sets of values of an electric field at different points in time; does not use more than one differential equation; and is generated based on observed functioning of a second module that is more computationally expensive than the first module.