# polyfit (MathScript RT Module Function)

LabVIEW 2012 MathScript RT Module Help

Edition Date: June 2012

Part Number: 373123C-01

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Owning Class: polynomials

Requires: MathScript RT Module

## Syntax

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

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

## Description

Computes a polynomial of a specified degree that fits the input data using the least-squares method.

Examples

## Inputs

Name Description
x Specifies the x-coordinates of the data you want to fit. x is a vector.
y Specifies the y-coordinates of the data you want to fit. y is a vector of the same length as x.
n Specifies the degree of the polynomial you want to fit against x and y. n must be less than the length of x. n is a positive integer.

## Outputs

Name Description
p Returns the coefficients in descending order of the polynomial fit. p is a vector.
s Returns the Cholesky factor of the Vandermonde matrix.
mu Returns the mean and standard deviation of x. LabVIEW uses these values to normalize x to improve the fit. mu is a vector. The first element of mu is the mean, and the second element of mu is the standard deviation.

## Details

The following table lists the support characteristics of this function.

 Supported in the LabVIEW Run-Time Engine Yes Supported on RT targets Yes Suitable for bounded execution times on RT Not characterized

## Examples

[P, S] = polyfit(1:10, rand(1, 10), 5)

[P, S, MU] = polyfit(1:10, [3, 3, 3, 4, 5, 6, 10, 12, 14, 15], 5)