DataFit

DataFit is an advanced CAD application whose purpose is to help you perform nonlinear regression (curve fitting), data plotting and statistical analysis.

Create new projects and import/export data

The GUI looks clean and allows you to define a new project by specifying the number of independent variables and showing standard deviation column.
You may import data from plain text, DAT or CSV file format or directly from any ODBC sources, such as Microsoft Access, dBase, Excel, Oracle, Paradox, Visual FoxPro and SQL Server. The information may be exported to the same files formats as the input ones. Printing data is also possible.
What’s more, you are allowed to enter data by typing it into a standard spreadsheet interface or by cutting and pasting it from other programs.

Calculations and results

DataFit is able to process linear and nonlinear regression models with up to 20 independent variables and supports variable selection (data mining).
The application lets you choose between a wide range of predefined two and three dimensional nonlinear regression models, which are usually employed in scientific and statistical tool.
In case the predefined regression models are not what you need, you can create user-defined ones, which may have up to 100 fitting parameters or variables. In addition, you can assign rule-based initial estimates and provide the analytical derivatives.
DataFit employs the Levenberg-Marquardt method for carrying out the nonlinear regression operations. The linear or nonlinear regression mode can be applied on a single model, groups of models or all of the models available.
Another handy feature of the utility allows an automatic sorting mode as regression models are solved based on different criteria, such as residual sum of squares and correlation coefficient. Logs include information about the regression process and errors.

Detailed reports

DataFit displays comprehensive reports about each solved regression model, such as number of observations, missing observations and nonlinear iterations, sum of residuals, average residual, coefficient of multiple determination, variance analysis, and data table with details about the entered, calculated and residual data.
The tool lets you export the results and data tables to XLS or HTML file format, automatically generate source code, work with a built-in data calculator that supports mathematical and statistical operations on curves, discreet data or numbers, as well as create 2D and 3D plots of equations, data and/or regression models.

Bottom line

All things considered, DataFit proves to be a reliable scientific and engineering tool that impresses with its support for a large number of calculations, and is suitable especially for professional users.