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Re: visualizing fields near charged objects

At 8:12 AM -0500 2/9/01, Ludwik Kowalski wrote:
John Mallinckrodt wrote:

With everybody implementing cylindrical coordinate spreadsheet
solutions, I thought I'd better jump in there as well. ...

My code uses rectangular coordinates (square cells in 2 dim) for
an object with cylindrical geometry. This is silly. But I am not
sure how to implement the "iterative averaging" for cylindrical
cells. So I have some questions.

For square cells we perform simple horizontal and vertical
averaging between neighbors. (4 cells in 2-dim or 6 in 3-dim).
This seems to be natural for cells of equal volume. But cells
of a cylindrical grid usually do not have that property.

1) Is it appropriate to perform simple averaging for usual
cylindrical cells (dr=const)?

2) If not then what to do? Should it be a weighted average
each time (bigger neighbor has stronger influence)?

Laplace's equation tells you that you should weigh your cells
ba a factor proportional to the radius. That makes a very simple
cell formula.