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The First Stage: Finding the Points

In the univariate case the zeros of Jacobi-polynomials give Gauss-Jacobi quadratures which are distinguished by highest possible degree of exactness. Moreover, these quadratures have positive weights from which convergence of these formulae is guaranteed.

To advance to the multivariate case, an interpretation of the zeros of the Jacobi polynomials is helpful. The zeros of these orthogonal polynomials are closely connected to movable charges situated on a metal rod which is represented by the real interval tex2html_wrap_inline3359. In the state of equilibrium the potential energy of the charge distribution is minimized and their locations coincide with the zeros of the Jacobi polynomials. For more details see Stroud and Secrest [24, p. 17,].

Thus a minimization of the potential energy of a point distribution on the sphere is a good criterion for an appropriate node distribution.

With tex2html_wrap_inline3361 the Euclidian norm in tex2html_wrap_inline3363 we get for electrical charged point particles at locations tex2html_wrap_inline3365 the potential energy
equation720

and thus the nonlinear optimization problem
  eqnarray229
which is a facility dispersion problem on the sphere. In computational physics and chemistry, this problem is also known as Thomson's problem.


next up previous
Next: The Second Stage: Finding Up: A Two-Stage Approach Previous: A Two-Stage Approach

Joerg Fliege
Thu Dec 23 19:39:35 CET 1999