The two inputs X and Y are vectors defining a set of N points. The function uses Lagrange's method to find the N-1th order polynomial that passes through all these points, and returns in P the N coefficients defining that polynomial. Then, polyval(P,X) = Y.
R returns the x co-ordinates of the N-1 extrema/inflection points of the resulting polynomial (roots of its derivative), and S returns the value of the polynomial at those points.
For a general-purpose way to find a smooth curve connecting points, you probably want to use SPLINE instead.
Dan Ellis (2022). Lagrange Interpolator Polynomial (https://www.mathworks.com/matlabcentral/fileexchange/13151-lagrange-interpolator-polynomial), MATLAB Central File Exchange. Retrieved .
MATLAB Release Compatibility
Platform CompatibilityWindows macOS Linux
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!Start Hunting!