![]() ![]() |
De J. C. Pezzullo This page lets you fit any function of up to eight parameters to a set of data. Just specify the function, the data points, and initial guesses to the parameters. When you click the Iterate button, the JavaScript program refines these estimates to produce what should be a better set of parameters. This process is iterative, and with good guesses (and good luck) usually converges to the least squares solution in five to ten iterations. This program can also fit nonlinear Least-Absolute-Value curves and Percentile Curves (having a specified fraction of the points below the curve). The current implementation is limited to eight parameters and eight independent variables. These arbitrary limits could be increased without much trouble if necessary. I don't know what the maximum number of data points is; it's probably dependent on your browser's maximum string size, since the contents of the Data and Results windows are treated as large text strings. I've used this page to fit 500-point datasets with no problems.
The fields below are pre-loaded with a simple example: the
temperature of a cup of water as it cools from boiling hot to room temperature
over the course of an hour, being fit to Newton's Law of Cooling: |