sfit

Constructor for sfit object

Syntax

surfacefit = sfit(fittype,coeff1,...,coeffn)

Description

surfacefit = sfit(fittype,coeff1,...,coeffn) constructs the sfit object surfacefit using the model type specified by the fittype object and the coefficient values coeff1, coeff2, etc.

An sfit object encapsulates the result of fitting a surface to data. They are normally constructed by calling the fit function, or interactively by exporting a fit from the Curve Fitter app to the workspace. You can get and set coefficient properties of the sfit object.

You can treat an sfit object as a function to make predictions or evaluate the surface at values of X and Y.

Like the cfit class, sfit inherits all fittype methods.

Note

sfit is called by the fit function when fitting fittype objects to data. To create an sfit object that is the result of a regression, use fit.

You should call sfit directly only if you want to assign values to coefficients and problem parameters of a fittype object without performing a fit.

Methods of sfit objects:

argnames	Input argument names of cfit, sfit, or fittype object
category	Category of fit of cfit, sfit, or fittype object
coeffnames	Coefficient names of cfit, sfit, or fittype object
dependnames	Dependent variable of cfit, sfit, or fittype object
formula	Formula of cfit, sfit, or fittype object
indepnames	Independent variable of cfit, sfit, or fittype object
islinear	Determine if cfit, sfit, or fittype object is linear
numargs	Number of input arguments of cfit, sfit, or fittype object
numcoeffs	Number of coefficients of cfit, sfit, or fittype object
probnames	Problem-dependent parameter names of cfit, sfit, or fittype object
probvalues	Problem-dependent parameter values of cfit or sfit object
quad2d	Numerically integrate sfit object
setoptions	Set model fit options
sfit	Constructor for sfit object
type	Name of cfit, sfit, or fittype object

Examples

Make predictions or evaluate the surface values of X and Y

You can treat an sfit object as a function to make predictions or evaluate the surface at values of X and Y.

        x = 3 - 6 * rand( 49, 1 );
        y = 3 - 6 * rand( 49, 1 );
        z = peaks( x, y );
        sf = fit( [x, y], z, 'poly32' );
        zhat = sf( mean( x ), mean( y ) )

Input Arguments

fittype — Model type

fittype (default)

Model type the sfit function uses to construct the sfit object, specified as a fittype constructed with the fittype function.

Example: fittype('linearinterp')

coeff1,...,coeffn — Coefficient values

scalar (default)

Coefficient values of the sfit object, specified as scalars.

Data Types: single | double

Output Arguments

surfacefit — sfit object

sfit

Function output, returned as an sfit object.

Version History

Introduced in R2009a