chebyshev_interp_1d, an Octave code which determines the combination of Chebyshev polynomials which interpolates a set of data, so that p(x(i)) = y(i).
The code needs the R8LIB library. The test program needs the TEST_INTERP library.
The computer code and data files described and made available on this web page are distributed under the MIT license
chebyshev_interp_1d is available in a C version and a C++ version and a Fortran90 version and a MATLAB version and an Octave version and a Python version.
barycentric_interp_1d, an Octave code which defines and evaluates the barycentric Lagrange polynomial p(x) which interpolates a set of data, so that p(x(i)) = y(i). the barycentric approach means that very high degree polynomials can safely be used.
chebyshev, an Octave code which computes the Chebyshev interpolant/approximant to a given function over an interval.
chebyshev_series, an Octave code which can evaluate a Chebyshev series approximating a function f(x), while efficiently computing one, two or three derivatives of the series, which approximate f'(x), f''(x), and f'''(x), by Manfred Zimmer.
clausen, an Octave code which evaluates a Chebyshev approximant to the clausen function cl2(x).
divdif, an Octave code which uses divided differences to compute the polynomial interpolant to a given set of data.
hermite_polynomial, an Octave code which computes the Hermite interpolant, a polynomial that matches function values and derivatives.
lagrange_interp_1d, an Octave code which defines and evaluates the Lagrange polynomial p(x) which interpolates a set of data, so that p(x(i)) = y(i).
nearest_interp_1d, an Octave code which interpolates a set of data using a piecewise constant interpolant defined by the nearest neighbor criterion.
newton_interp_1d, an Octave code which finds a polynomial interpolant to data using Newton divided differences.
pwl_interp_1d, an Octave code which interpolates a set of data using a piecewise linear interpolant.
r8lib, an Octave code which contains many utility routines using double precision real (r8) arithmetic.
rbf_interp_1d, an Octave code which defines and evaluates radial basis function (RBF) interpolants to 1d data.
shepard_interp_1d, an Octave code which defines and evaluates Shepard interpolants to 1d data, which are based on inverse distance weighting.
spline, an Octave code which constructs and evaluates spline interpolants and approximants.
test_interp, an Octave code which defines a number of test problems for interpolation, provided as a set of (x,y) data.
test_interp_1d, an Octave code which defines test problems for interpolation of data y(x), depending on a 2d argument.
vandermonde_interp_1d, an Octave 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.