NLREG

NLREG is a statistical analysis program designed for performing nonlinear regression analysis and curve fitting. It is intended for use by businesses of all sizes, including small, medium, and large organizations. According to the vendor, NLREG is commonly used by professionals in various industries such as universities, research institutions, laboratories, government agencies, data analysts, statisticians, scientists, and researchers.

Key Features

Nonlinear Regression and Curve Fitting: NLREG is a statistical analysis program that performs linear and nonlinear regression analysis, surface and curve fitting. According to the vendor, it determines the values of parameters for an equation, specified by the user, that cause the equation to best fit a set of data values.

Full Programming Language: NLREG features a full programming language with a syntax similar to C for specifying the function that is to be fitted to the data. According to the vendor, the programming language allows users to compute intermediate work variables, use conditionals, and iterate in loops. Piecewise functions that change form over different domains can be easily constructed.

True Nonlinear Regression Analysis: NLREG performs true nonlinear regression analysis and curve fitting, without transforming the function into a linear form. According to the vendor, it can handle functions that are impossible to linearize. The minimization of the sum of squared residual values is based on the true nonlinear value rather than a linearized transformation.

Data Visualization and Analysis: NLREG can generate plots of the data points and the fitted equation. It can plot the distribution of residual values and produce a normal probability plot. According to the vendor, auxiliary statistics such as Student's t, Prob(t), F, Prob(F), Durbin-Watson, and correlation and covariance matrices can be computed.

Variable and Parameter Handling: The Standard version of NLREG can fit up to 5 variables and parameters to the data observations. The Advanced version can handle up to 2000 variables and parameters. According to the vendor, NLREG can generate 3D surface plots.

Multivariate Nonlinear Function Analysis: NLREG can be used to find the root or minimum value of a general multivariate, nonlinear function. According to the vendor, it can be used in a special form where the independent variable is omitted, allowing for circular regression where a circle is fitted to a set of data points.

DLL and COM Object Versions: DLL and COM object versions of NLREG are available for applications that want to call NLREG as an "engine" to perform regressions. According to the vendor, examples of calling the NLREG COM Library using Visual Basic are provided.