CFLab: A MATLAB GUI program for decomposing sediment grain size distribution using Weibull functions

Abstract Curve fitting is a powerful tool that has been widely used to explore sediment grain size distributions. Open-source software designed for realization of the technique, however, is scarce. Here we provide a flexible and efficient MATLAB® GUI (Graphic User Interface) program CFLab (Curve Fitting Lab) to perform curve fitting on sediment grain size distributions using Weibull Probability Distribution Functions. CFLab deals with one grain size distribution each time. It considers the curve fitting problem as a problem of constrained nonlinear programming. In CFLab, an initial solution for this problem can be set either by designating a series of numbers for the undetermined parameters in the problem or by using a novel interactive strategy. The trust-region-reflective algorithm is used to solve the problem. Major results generated by CFLab include the percentages and grain size distributions of subpopulations fitting the raw grain size distribution data and many statistic parameters of the subpopulations calculated using two different methods. CFLab can be used to study a wide range of eolian and water-deposited sediments. A short case study is presented to demonstrate that the evolution of sediment grain size distributions in a specific sedimentary environment can be explored using CFLab.