Please will *anyone* who wants to help Joy and Fred
write a piece of computer code which
(a) reads two files each containing N directions u_k and v_k,
(b) accepts as inputs from the user two directions a and b, and
(c) calculates E(a, b) = 1/N sum_k {sign(a . u_k)} {sign(b . v_k)}
treating of course, the product A_k B_k here as a geometric product, whatever that means. Isn't the product of two numbers +/-1 the same whether or not we think of the product as geometric? Possibly Fred is thinking of the dot product between real three-dimensional vectors a and u (and similarly b and v) as being some other new product? If that is the case, please define the mappings ".", "sign", and the product between A_k and B_k.
All directions to be specified by vectors in R^3, represented by Cartesian coordinates (x, y, z).
Earlier, I wrote an R program which did this task. Other people supplied Perl, Python, Excel, Mathematica. No one complained about those programs. They have all been tested and give the same output on the same inputs. However they were not written by experts on Joy's model and apparently there is something badly wrong with all of them.
PS: in case that the N u_k's are a large random sample from the uniform distribution on S^2, and a and b are vectors of unit length, and for each k, v_k = - u_k, we want E(a, b) to approximately equal - a . b (ordinary dot product).
PPS: since the u_k, v_k, a and b all specify directions of classical angular momentum of classical massive spinning rigid bodies in classical three dimensional space (zero gravity, vacuum), they all should be non-zero when represented as vectors in R^3. The lengths of the vectors (provided they are positive) should be irrelevant. For simplicity all vector-directions could be taken to have unit length.