pwl_approx_1d, a MATLAB code which defines and evaluates a piecewise linear function, using NC "control points", which approximates a set of ND data points (x(i),y(i)).
PWL_APPROX_1D needs access to the R8LIB library. The test code also needs access to the TEST_INTERP_1D library.
The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.
pwl_approx_1d is available in a C version and a C++ version and a FORTRAN90 version and a MATLAB version.
bernstein_polynomial, a MATLAB code which evaluates the Bernstein polynomials, useful for uniform approximation of functions;
lagrange_approx_1d, a MATLAB code which defines and evaluates the Lagrange polynomial p(x) of degree m which approximates a set of nd data points (x(i),y(i)).
pwl_interp_1d, a MATLAB code which interpolates a set of data using a piecewise linear function.
r8lib, a MATLAB code which contains many utility routines using double precision real (R8) arithmetic.
spline, a MATLAB code which constructs and evaluates spline interpolants and approximants.
test_approx, a MATLAB code which defines test problems for approximation, provided as a set of (x,y) data.
test_interp, a MATLAB code which defines a number of test problems for interpolation, provided as a set of (x,y) data.
test_interp_1d, a MATLAB code which defines test problems for interpolation of data y(x), depending on a 2D argument.
vandermonde_approx_1d, a MATLAB code which finds a polynomial approximant to data of a 1D argument by setting up and solving an overdetermined linear system for the polynomial coefficients, involving the Vandermonde matrix.