SIMP: a computer program in BASIC for nonlinear curve fitting.

A computer program for nonlinear regression analysis is described. The program, SIMP, is written in BASIC for use with a wide range of microcomputers. The simplex algorithm is used to minimize the sum of the squared residuals around the fitted line, and the data can be weighted if required. The program is applicable to a wide range of pharmacological procedures requiring curve fitting, and the analysis of protein-binding data is given as an example.