test_interp_fun, a Python code which defines formulas for functions used to test interpolation algorithms at arbitrary arguments.
The related packages TEST_INTERP and TEST_APPROX provide discrete data sets of (x,y) pairs. However, when the convergence rate of an interpolation process is of interest, it is important to be able to sample an underlying but "unknown" function at an increasing number of points. This library provides a few functions which are known to cause problems for certain kinds of interpolation schemes.
The information on this web page is distributed under the MIT license.
test_interp_fun is available in a C version and a C++ version and a Fortran77 version and a Fortran90 version and a MATLAB version and an Octave version and a Python version.
chebyshev, a Python code which computes the Chebyshev interpolant/approximant to a given function over an interval.
divdif, a Python code which includes many routines to construct and evaluate divided difference interpolants.
lagrange_interp_1d, a Python code which defines and evaluates the Lagrange polynomial p(x) which interpolates a set of data, so that p(x(i)) = y(i).
rbf_interp_1d, a Python code which defines and evaluates radial basis function (RBF) interpolants.
shepard_interp_1d, a Python code which defines and evaluates Shepard interpolants to 1d data, which are based on inverse distance weighting.
test_interp, a Python code which defines a number of test problems for interpolation, provided as a set of (x,y) data.
vandermonde_interp_1d, a Python code which finds a polynomial interpolant to a function of 1d data by setting up and solving a linear system for the polynomial coefficients, involving the Vandermonde matrix.
