Eureqa

Eureqa (pronounced "eureka") is a software tool for detecting equations and hidden mathematical relationships in your data. Its goal is to identify the simplest mathematical formulas which could describe the underlying mechanisms that produced the data. Eureqa is free to download and use.
The Eureqa application uses a special layout:
1. Each column corresponds to a single variable of your data (e.g. "time", or "oxygen concentration")
2. The first row, labeled "desc" is for commenting and describing what the variable means or measured
3. The second row, labeled "var" is the symbol given to each variable (e.g. "x" or "CO2")
4. All remaining rows correspond to simultaneous data measurements and values
You can paste data into cells from many applications that contain spreadsheets such as Microsoft Excel, Matlab's array editor, or any tabseparatedvalue text file.
The license of this software is Free Trial Software, the price is $2499.00, you can free download and get a free trial.