Fast Polynomial Curve and Surface Fitting

Fast polynomial curve and surface fitting via LLS. The functions are significantly faster than the default functions for ordinary problems

Syntax

[k,r] = pcfit(x,y,n)

y = pcval(k,x)

[k,r] = psfit(x,y,z,n)

z = psval(k,x,y,n)

Description

pcfit Polynomial curve fitting

pcval Polynomial curve evaluation

psfit Polynomial surface fitting

psval Polynomial surface evaluation

k process coefficients

r residuals

x x-coordinate

y y-coordinate

z z-coordinate

n process order

Fast polynomial process fitting and evaluation via linear least squares (LLS). Significant speed increases over the MATLAB's functions for low and medium sized problems at the cost of numerical stability and robustness. The direct resolution of the linear system with iteratively-assembled Vandermonde matrices is the key advantage of the code, as well as the surface evaluation assuming the coefficients form an upper-triangular matrix.

Examples

demo1
demo2