On the discretisation of the double layer integral operator for surfaces of revolution (Q1070759)

From authors' summary: The double layer integral operator W on some surface S is discretised in the form \[ WV(P)\sim \sum^{N}_{j=1}V(P_ j)\Omega (P,\Delta_ j),\quad P\in S, \] where \(\Omega\) (P,\(\Delta)\) is the solid angle of a piece \(\Delta_ j\) of S seen from P and \(P_ j\) is a point in \(\Delta_ j\). For axisymmetric problems, if each \(\Delta_ j\) is a zone of the surface of revolution, \(\Omega (P,\Delta_ j)\) is a complete elliptic integral of the third kind which can be computed by the Bartky-Bulirsch algorithm.