Easily fit any model to a set of x, y data. Several preset models are provided, you can start with one of these and modify it to your liking. When you click "Optimize", your model is parsed using the math.js expression parser. Then the parameters are optimized using the Nelder-Mead (simplex) method to find a local minimum of the squared error. In some cases, you may need to press "Optimize" more than once. For models with many parameters, you may need to provide some good guess values in the "Parameters" field.