Positive constrained approximation via RBF-based partition of unity method
For researchers in approximation theory and applied sciences needing positive interpolants, this is an incremental improvement over existing methods.
This paper improves the accuracy of positive RBF-based partition of unity interpolants by locally adding constraints and selecting the optimal number via an a priori error estimate, achieving better accuracy than previous global approaches.
In this paper, we discuss the problem of constructing Radial Basis In this paper, we discuss the problem of constructing Radial Basis Function (RBF)-based Partition of Unity (PU) interpolants that are positive if data values are positive. More specifically, we compute positive local approximants by adding up several constraints to the interpolation conditions. This approach, considering a global approximation problem and Compactly Supported RBFs (CSRBFs), has been previously proposed. Here, the use of the PU technique enables us to intervene only locally and as a consequence to reach a better accuracy. This is also due to the fact that we select the optimal number of positive constraints by means of an a priori error estimate and we do not restrict to the use of CSRBFs. Numerical experiments and applications to population dynamics are provided to illustrate the effectiveness of the method in applied sciences.