It uses Gauss-Siedel Method of load-flow analysis. Using this m-file, if two buses are not connected, enter 'inf' for resistance and inductance between them. If PV bus has no limit on reactive power, enter 'inf' for upper limit of Q and '-inf' for lower limit of Q.
Niranjan Bhujel (2019). Load Flow Analysis using Gauss-Siedel Method (https://www.mathworks.com/matlabcentral/fileexchange/64107-load-flow-analysis-using-gauss-siedel-method), MATLAB Central File Exchange. Retrieved .