The wxAMPS program is an update of the popular solar cell simulation tool AMPS (Analysis of Microelectronic and Photonic Structures). The user interface of wxAMPS uses a cross-platform library and provides quick data entry and improved visualization. Beyond the original AMPS kernel, wxAMPS incorporates two tunneling models and a new algorithm combining the Newton and Gummel methods. The incorporation of a trap-assisted tunneling model makes more precise simulation of multi-junction solar cells possible. The combined Newton and Gummel method solutions improve stability of the code and permit both tunneling models to function well within the algorithm. Based on the option for an unlimited number of layers in the simulation, modeling graded solar cells can be implemented easily in wxAMPS. (C) 2011 Elsevier B.V. All rights reserved.