A deterrent to application of rational basis functions over algebraic elements has been the need to compute denominator polynomials (element adjoints) from multiple points of the element boundary. Dasgupta devised a simple algorithm for eliminating this problem for convex polygons. This algorithm is described here and generalized to elements with curved sides. © 2007 Elsevier Ltd. All rights reserved.
Dasgupta, G., & Wachspress, E. (2008). The adjoint for an algebraic finite element. Computers and Mathematics with Applications, 55(9), 1988–1997. https://doi.org/10.1016/j.camwa.2004.03.021