# test_interp_1d

test_interp_1d, a Python code which defines test functions y(x) that may be used to test interpolation algorithms involving a 1D argument x.

### Languages:

test_interp_1d is available in a C version and a C++ version and a FORTRAN90 version and a MATLAB version and a Python version.

### Related Data and Programs:

BARYCENTRIC_INTERP_1D, a Python 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_INTERP_1D, a Python code which determines the combination of Chebyshev polynomials which interpolates a set of data, so that p(x(i)) = y(i).

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).

NEAREST_INTERP_1D, a Python code which interpolates a set of data using a piecewise constant interpolant defined by the nearest neighbor criterion.

NEWTON_INTERP_1D, a Python code which finds a polynomial interpolant to data using Newton divided differences.

PWL_INTERP_1D, a Python code which interpolates a set of data using a piecewise linear function.

RBF_INTERP_1D, a Python code which defines and evaluates radial basis function (RBF) interpolants to 1D data.

SHEPARD_INTERP_1D, a Python code which defines and evaluates Shepard interpolants to 1D data, based on inverse distance weighting.

VANDERMONDE_INTERP_1D, a Python code which finds a polynomial interpolant to data y(x) of a 1D argument, by setting up and solving a linear system for the polynomial coefficients, involving the Vandermonde matrix.

### Source Code:

The test plots each function:

Last revised on 05 July 2017.