New Insights in Boundary-only and Domain-type RBF Methods

This paper has made some significant advances in the boundary-only and domain-type RBF techniques. The proposed boundary knot method (BKM) is different from the standard boundary element method in a number of important aspects. Namely, it is truly meshless, exponential convergence, integration-free (of course, no singular integration), boundary-only for general problems, and leads to symmetric matrix under certain conditions (able to be extended to general cases after further modified). The BKM also avoids the artificial boundary in the method of fundamental solution. An amazing finding is that the BKM can formulate linear modeling equations for nonlinear partial differential systems with linear boundary conditions. This merit makes it circumvent all perplexing issues in the iteration solution of nonlinear equations. On the other hand, by analogy with Green's second identity, we also presents a general solution RBF (GSR) methodology to construct efficient RBFs in the domain-type RBF collocation method and dual reciprocity method. The GSR approach first establishes an explicit relationship between the BEM and RBF itself on the ground of the potential theory. This paper also discusses some essential issues relating to the RBF computing, which include time-space RBFs, direct and indirect RBF schemes, finite RBF method, and the application of multipole and wavelet to the RBF solution of the PDEs.