Lagrange interpolation estimates a function at a reference position x from known values of the function at distinct non-uniformly spaced points x1, ....., xn. Here, the corresponding η-point ...

Mathematics of Computation, Vol. 71, No. 240 (Oct., 2002), pp. 1421-1430 (10 pages) Finite element derivative superconvergent points for harmonic functions under local rectangular mesh are ...