polyfit

Fit a polynomial to a set of paired data.

Syntax

p = polyfit(x,y,n)

[p,s,t] = polyfit(x,y,n)

Inputs

x
Values in first dimension of paired data.
Type: double
Dimension: vector
y
Values in second dimension of paired data.
Type: double
Dimension: vector
n
Order of the fit.
Type: integer
Dimension: scalar

Outputs

p
The fitted polynomial coefficients, stored in descending order of powers.
s
A structure containing information about the fit. The following are supported.
'normr' is the norm of the residuals vector.
'yf' contains the fitted y values.
t
A transform vector containing t(1)=mean(x) and t(2)=std(x). When t is present, x is shifted by t(1) and scaled by t(2) prior to the fit.

Example

Second order polyfit example.

p=polyfit([1,2,3,4],[4,8,18,32],2)
p = [Matrix] 1 x 3
 2.50000  -3.10000   4.50000