Declaration: TCurveFit.CalcPolyFit (const nOrder: byte; var kArray: array of double; var FitQual: double; var NearSingular: boolean): boolean;
The method CalcPolyFit calculates the best fit for a polynomial of order nOrder. The order of the polynomial is restricted to values between 1 and MaxPolyFitOrder. The variable array parameter kArray returns the polynomial coefficients, the variable parameter FitQual returns the goodness of fit. The function CalcPolyFit returns a TRUE value if the fit has been calculated successfully, and the returned parameters are valid. Numerical instabilities which may arise from near-singular equations are indicated by returning a TRUE value in the variable parameter NearSingular. In this case the calculated polynomial coefficients should not be used.

Hint: The number of data used for the polynomial fit has to exceed the order of the polynomial at least by one.