Test Interpolation Data Z(X,Y) of a 2D Argument

TEST_INTERP_2D is a C++ library which defines test problems for interpolation of data z(x,y) depending on a 2D argument.

TEST_INTERP_2D requires access to the R8LIB library.


The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.


TEST_INTERP_2D is available in a C version and a C++ version and a FORTRAN77 version and a FORTRAN90 version and a MATLAB version and a Python version.

Related Data and Programs:

LAGRANGE_INTERP_2D, a C++ library which defines and evaluates the Lagrange polynomial p(x,y) which interpolates a set of data depending on a 2D argument that was evaluated on a product grid, so that p(x(i),y(j)) = z(i,j).

PADUA, a C++ library which returns the points and weights for Padu sets, useful for interpolation in 2D. GNUPLOT is used to plot the points.

PWL_INTERP_2D, a C++ library which evaluates a piecewise linear interpolant to data defined on a regular 2D grid.

R8LIB, a C++ library which contains many utility routines, using double precision real (R8) arithmetic.

RBF_INTERP_2D, a C++ library which defines and evaluates radial basis function (RBF) interpolants to 2D data.

SHEPARD_INTERP_2D, a C++ library which defines and evaluates Shepard interpolants to 2D data, based on inverse distance weighting.

TEST_INTERP_1D, a C++ library which defines test problems for interpolation of data y(x), depending on a 1D argument.

TEST_INTERP_ND, a C++ library which defines test problems for interpolation of data z(x), depending on an M-dimensional argument.

TOMS886, a C++ library which defines the Padua points for interpolation in a 2D region, including the rectangle, triangle, and ellipse, by Marco Caliari, Stefano de Marchi, Marco Vianello. This is a C++ version of ACM TOMS algorithm 886.

VANDERMONDE_INTERP_2D, a C++ library which finds a polynomial interpolant to data z(x,y) of a 2D argument by setting up and solving a linear system for the polynomial coefficients, involving the Vandermonde matrix.


  1. Richard Franke,
    A Critical Comparison of Some Methods for Interpolation of Scattered Data,
    Naval Postgraduate School Technical Report,
    NPS-53-79-003, 1979.
  2. Robert Renka, Ron Brown,
    Algorithm 792: Accuracy Tests of ACM Algorithms for Interpolation of Scattered Data in the Plane,
    ACM Transactions on Mathematical Software,
    Volume 25, Number 1, March 1999, pages 78-94.
  3. Donald Shepard,
    A two-dimensional interpolation function for irregularly spaced data,
    ACM '68: Proceedings of the 1968 23rd ACM National Conference,
    ACM, pages 517-524, 1969.

Source Code:

Examples and Tests:

List of Routines:

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Last revised on 05 October 2012.