Copyright © 2016 by *MTR* Software • All Rights Reserved • support@fitall.com
*What FitAll Does*

*FitAll* is a general-purpose, nonlinear regression analysis (curve fitting) program that can be used to fit a set of experimental data to any of the defined functions (models).

*FitAll* fits data to continuous, single-valued functions with the general form:

##### Y

_{i}##### =

#### f

##### (X

_{ij}##### , K

_{j}##### , P

_{j}##### )

and *implicit* functions with the general form:

##### Y

_{i}##### =

#### f

##### (

**Y**_{i}##### , X

_{ij}##### , K

_{j}##### , P

_{j}##### )

,

in which:

•

Y_{i} is the dependent variable (measured value of the function for the i^{th} data point).

•

X_{ij} is the set of j independent variables for the i^{th} data point.

•

K_{k} is a set of k constants that can be modified at runtime.

•

P_{p} is the set of p parameters that are evaluated.

•

**Linear Least Squares (lls):** minimizes the sum of the squares of the deviations between the observed and calculated values of a function that is linear in its parameters.

•

**Nonlinear Least Squares (nls):** minimizes the sum of the squares of the deviations between the observed and calculated values.

•

**Nonlinear Least Absolute Deviations (nlad):** minimizes the absolute deviations between the observed and calculated values.

Three different regression analysis methods can be used to obtain the best fit:

The regression analysis can be **weighted** using four different weighting schemes.

The data can be **smoothed** using the Boxcar and Fast Fourier Transform methods.

*FitAll* reports the standard deviation of the overall fit as well as that of each of the resolved parameters.

All results and reports can be printed, saved to a file, copied to the clipboard or transferred to a MS Word, LibreOffice Writer or OOo Writer document.