**lagrange_interp_2d_test**,
a MATLAB code which
calls lagrange_interp_2d(), 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).

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

lagrange_interp_2d, a MATLAB code 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).

- lagrange_interp_2d_test.m, calls all the tests;
- lagrange_interp_2d_test.sh, runs all the tests;
- lagrange_interp_2d_test.txt, the output file.

- lagrange_interp_2d_test01.m, tests the interpolation condition, and the approximation power of the interpolant at the midpoints.
- lagrange_interp_2d_test02.m, plots a linear interpolant to a triangulation of the original data, and the Lagrange interpolant.

**lagrange_interp_2d_test02()** plots a piecewise linear interpolant to
the original data, and the Lagrange interpolant.

- p01_data.png, a plot of the piecewise linear interpolant to the data for problem p01;
- p01_poly01.png, a plot of the polynomial interpolant for problem p01, degree 1;
- p01_poly02.png, a plot of the polynomial interpolant for problem p01, degree 2;
- p01_poly03.png, a plot of the polynomial interpolant for problem p01, degree 3;
- p01_poly04.png, a plot of the polynomial interpolant for problem p01, degree 4;
- p01_poly08.png, a plot of the polynomial interpolant for problem p01, degree 8;
- p02_data.png, a plot of the piecewise linear interpolant to the data for problem p02;
- p02_poly01.png, a plot of the polynomial interpolant for problem p02, degree 1;
- p02_poly02.png, a plot of the polynomial interpolant for problem p02, degree 2;
- p02_poly03.png, a plot of the polynomial interpolant for problem p02, degree 3;
- p02_poly04.png, a plot of the polynomial interpolant for problem p02, degree 4;
- p02_poly08.png, a plot of the polynomial interpolant for problem p02, degree 8;
- p03_data.png, a plot of the piecewise linear interpolant to the data for problem p03;
- p03_poly01.png, a plot of the polynomial interpolant for problem p03, degree 1;
- p03_poly02.png, a plot of the polynomial interpolant for problem p03, degree 2;
- p03_poly03.png, a plot of the polynomial interpolant for problem p03, degree 3;
- p03_poly04.png, a plot of the polynomial interpolant for problem p03, degree 4;
- p03_poly08.png, a plot of the polynomial interpolant for problem p03, degree 8;
- p04_data.png, a plot of the piecewise linear interpolant to the data for problem p04;
- p04_poly01.png, a plot of the polynomial interpolant for problem p04, degree 1;
- p04_poly02.png, a plot of the polynomial interpolant for problem p04, degree 2;
- p04_poly03.png, a plot of the polynomial interpolant for problem p04, degree 3;
- p04_poly04.png, a plot of the polynomial interpolant for problem p04, degree 4;
- p04_poly08.png, a plot of the polynomial interpolant for problem p04, degree 8;
- p05_data.png, a plot of the piecewise linear interpolant to the data for problem p05;
- p05_poly01.png, a plot of the polynomial interpolant for problem p05, degree 1;
- p05_poly02.png, a plot of the polynomial interpolant for problem p05, degree 2;
- p05_poly03.png, a plot of the polynomial interpolant for problem p05, degree 3;
- p05_poly04.png, a plot of the polynomial interpolant for problem p05, degree 4;
- p05_poly08.png, a plot of the polynomial interpolant for problem p05, degree 8;
- p06_data.png, a plot of the piecewise linear interpolant to the data for problem p06;
- p06_poly01.png, a plot of the polynomial interpolant for problem p06, degree 1;
- p06_poly02.png, a plot of the polynomial interpolant for problem p06, degree 2;
- p06_poly03.png, a plot of the polynomial interpolant for problem p06, degree 3;
- p06_poly04.png, a plot of the polynomial interpolant for problem p06, degree 4;
- p06_poly08.png, a plot of the polynomial interpolant for problem p06, degree 8;
- p07_data.png, a plot of the piecewise linear interpolant to the data for problem p07;
- p07_poly01.png, a plot of the polynomial interpolant for problem p07, degree 1;
- p07_poly03.png, a plot of the polynomial interpolant for problem p07, degree 3;
- p07_poly02.png, a plot of the polynomial interpolant for problem p07, degree 2;
- p07_poly04.png, a plot of the polynomial interpolant for problem p07, degree 4;
- p07_poly08.png, a plot of the polynomial interpolant for problem p07, degree 8;
- p08_data.png, a plot of the piecewise linear interpolant to the data for problem p08;
- p08_poly01.png, a plot of the polynomial interpolant for problem p08, degree 1;
- p08_poly02.png, a plot of the polynomial interpolant for problem p08, degree 2;
- p08_poly03.png, a plot of the polynomial interpolant for problem p08, degree 3;
- p08_poly04.png, a plot of the polynomial interpolant for problem p08, degree 4;
- p08_poly08.png, a plot of the polynomial interpolant for problem p08, degree 8;
- p09_data.png, a plot of the piecewise linear interpolant to the data for problem p09;
- p09_poly01.png, a plot of the polynomial interpolant for problem p09, degree 1;
- p09_poly02.png, a plot of the polynomial interpolant for problem p09, degree 2;
- p09_poly03.png, a plot of the polynomial interpolant for problem p09, degree 3;
- p09_poly04.png, a plot of the polynomial interpolant for problem p09, degree 4;
- p09_poly08.png, a plot of the polynomial interpolant for problem p09, degree 8;
- p10_data.png, a plot of the piecewise linear interpolant to the data for problem p10;
- p10_poly01.png, a plot of the polynomial interpolant for problem p10, degree 1;
- p10_poly02.png, a plot of the polynomial interpolant for problem p10, degree 2;
- p10_poly03.png, a plot of the polynomial interpolant for problem p10, degree 3;
- p10_poly04.png, a plot of the polynomial interpolant for problem p10, degree 4;
- p10_poly08.png, a plot of the polynomial interpolant for problem p10, degree 8;
- p11_data.png, a plot of the piecewise linear interpolant to the data for problem p11;
- p11_poly01.png, a plot of the polynomial interpolant for problem p11, degree 1;
- p11_poly02.png, a plot of the polynomial interpolant for problem p11, degree 2;
- p11_poly03.png, a plot of the polynomial interpolant for problem p11, degree 3;
- p11_poly04.png, a plot of the polynomial interpolant for problem p11, degree 4;
- p11_poly08.png, a plot of the polynomial interpolant for problem p11, degree 8;
- p12_data.png, a plot of the piecewise linear interpolant to the data for problem p12;
- p12_poly01.png, a plot of the polynomial interpolant for problem p12, degree 1;
- p12_poly02.png, a plot of the polynomial interpolant for problem p12, degree 2;
- p12_poly03.png, a plot of the polynomial interpolant for problem p12, degree 3;
- p12_poly04.png, a plot of the polynomial interpolant for problem p12, degree 4;
- p12_poly08.png, a plot of the polynomial interpolant for problem p12, degree 8;
- p13_data.png, a plot of the piecewise linear interpolant to the data for problem p13;
- p13_poly01.png, a plot of the polynomial interpolant for problem p13, degree 1;
- p13_poly02.png, a plot of the polynomial interpolant for problem p13, degree 2;
- p13_poly03.png, a plot of the polynomial interpolant for problem p13, degree 3;
- p13_poly04.png, a plot of the polynomial interpolant for problem p13, degree 4;
- p13_poly08.png, a plot of the polynomial interpolant for problem p13, degree 8;