As a help for me learning Dyadic vector analysis, I have been working on a Numpy class for manipulating Dyads. I am wondering if anyone else has any similar interests. Most of the impetus for the work comes from "Methods for Electromagnetic Field Analysis" by Ismo Lindell. In numerous searches I found no computer code dealing with Dyads. My biggest stumbling block so far is integrating the symbolism of Dyadic analysis into something understandable. Operator overloading isn't going to help me. For example in my program: A=dyad(a,b) where a and b are complex vectors B=dyad(c,d) " A.dmmd(B) is equivalent to double dyadic multiplication of the dyads A and B. :) In a book this would be written something like A xx B except that the x's would be aligned vertically. Ok, its an insane project. Rob. -- ----------------------------- The Numeric Python EM Project www.pythonemproject.com