The Nystr\"om method for the numerical solution of Fredholm integral equations of the second kind is generalized by decoupling the set of solution nodes from the set of quadrature nodes. The accuracy and efficiency of the new method is investigated for smooth kernels and complex 2D domains using recently developed moment-free meshless quadrature formulas on scattered nodes. Compared to the classical Nystr\"om method, our variant has a clear performance advantage, especially for narrow kernels. The decoupled Nystr\"om method requires the choice of a reconstruction scheme to approximate values at quadrature nodes from values at solution nodes. We prove that, under natural assumptions, the overall order of convergence is the minimum between that of the quadrature scheme and of the reconstruction scheme.

翻译：暂无翻译