BestCurvFit software for enzyme kinetics, Nonlinear Least squares, nonlinear minimization, robust, optimization, variable metric, Gauss-Newton, Levenberg-Marquardt

Purchase BestCurvFit $19.99 - New Version  

New and Improved Version 13.3  (November 17, 2024) 

Users of BestCurvFit are encouraged to download the latest version of BestCurvFit. Users with an active license can download and activate the software with their current activation code. If anyone encounters an issue with BestCurvFit, please let us know via our email (DrFrank88@gmail.com).

BestCurvFit performs nonlinear regression curve-fitting of data to kinetic models either defined by the user or selected from in internal library of 46 models. BestCurvFit is priced to make it affordable to professionals and students alike. But don't let the low price mislead you. BestCurvFit is robust and powerful using some of the most sophisticated regression algorithms, including Variable Metric, Gauss-Newton as modified by Marquardt-Levenberg , Conjugate Gradient, Hooke-Reeves, and Random search methods. Why pay hundreds and  yearly license fees when you can have curve-fitting software for a fraction of the cost. Best of all, there are no time limit restrictions or number of uses.

With just one-click of the mouse, BestCurvFit simplifies curve fitting your data to mathematical models. Select an equation from an internal library of 46 models or enter your own function, and BestCurvFit does the rest by fitting the curve to your data set, displaying the statistical results, model parameters, the best fit curve, and the residuals.

The BestCurvFit results of your curve-fit includes the fitted  parameters, their standard errors, their significance , confidence limits, correlation matrix, and measures of parameter redundancy like variance decomposition proportions and condition index, and eigenvalues and principle component values. 

An important measure of a good curve-fit is the residuals plot. BestCurvFIt includes statistic tests for the residuals plot. These tests include (1) Distribution-free Runs statistic test of the randomness of residuals, (2) F-test statistic to determines if the mean of the residuals is significantly different than zero, (3) Durbin-Watson statistic test of residuals to determine if a serial correlation exists, (4) Kolmogorov-Smirnov non-parametric, distribution-free, statistic test of residuals to determine whether positive and negative residuals come from the same distribution, (5) Hotelling's T-squared distribution (T²) multivariate statistic used to measure dissimilarity for outlier detection in the data set, and (6) Besseli0 function of residuals to detect outlying data. 

Nonlinear Least Squares Algorithm
The curve-fit procedure iteratively adjusts the parameters β of function f(x,β1,…,βp) to minimize the residual sum of squares (RSS or SSQR, X^2):

Where,
Xi and Yi are the data points to curve-fit to the function,
N is the total number of data points,
f(x,β1,…,βp) is the fitted function with dependent variables x and β,
p is the number of fitted parameters β,
Wi are the data weighting coefficients for each x and y point.
Initial estimates for each parameter must be provided to begin the minimization.
New best fit parameter estimates at each iteration is based on the partial derivatives of the fitted parameters for each x value. Partial derivatives are calculated using either numerical finite difference approximations or explicit formulas for some predefined functions.


Nonlinear regression curve-fitting software at an affordable price.
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Download the latest version of BestCurvFit 
Download the software zip file and then run BestCurvFit.exe to obtain the registration code to unlock the software on your computer.  Then purchase BestCurvFit using PayPal and email the registration code to us at DrFrank88@gmail.com  No Windows installation is required; just drop it into a folder and run. The zip file also contains 46 data file examples of the BestCurvFit model library.  
Note: The BestCurvFit.lic and BestCurvFit.ini files must reside in the same folder as BestCurvFit.exe.  A text editor (e.g., Notepad) must be used to create and save all data files. A Notepad is available in the File/Edit Data File menu to revise and edit data.dat files once the data file is Opened. 

Download and unZip the file in a folder (e.g., C:\MyBestCurvFit\) on a computer you choose to license the software, and then run BestCurvFit.exe to retrieve the "Registration Code". The lack of formal Windows installation is intentional, as it allows installation without administrative privileges (no dynamic link libraries (DLL) are used). After you've paid for the software using PayPal, email us the Registration Code at drfrank88@gmail.com and we'll send you the Activation Code to enter and fully activate the software. Once activated, do not delete or modify the ini or lic files contained therein as they are required to execute and run the software. We suggest that you make backup copies of both the BestCurvFit.lic and BestCurvFit.ini files for future reference.  BestCurvFit is copy-protected to run on one MS Windows  32 or 64-bit computer.
Note: BestCurvFit.zip has been scanned by Windows Defender. 

Note: If your browser flags the downloaded zip file with a cautionary warning, you have the option of selecting "keep"  to continue the download process. The BestCurvFit.zip file was  scanned with Microsoft Windows Defender and shown not to have any detectable threats.  The BestCurvFit software does not send any information back to us or anyone else, and it does not require a network connection to run.  It is a standalone executable file (no DLL files) . 

Disclaimer of 'False Positive' virus: BestCurvFit.exe is an independently distributed program, and as such it may be flagged as a 'false positive' by your antivirus/antimalware software. Therefore, it is advisable to create an exclusion for the BestCurvFit.exe software to avoid the appearance of 'false positive' errors during execution.