I am solving a time-dependent PDE and I want to evaluate the solution at each of the nodal points. I can easily get this information just by using
or for whatever time I want to look at instead of the end time. I want to get the average value of the result at the nodal points, but I only want to do it for a certain subset of all the nodal points. This would be simple enough if the nodal points were ordered in a nice pattern, but unfortunately they look like this:
Does anyone have an idea of how I might be able to determine which nodal points lie inside of the red line (this is a only a portion of the picture because it is zoomed in to give clarity) or some what to make them ordered?