1. A method of modeling the operation of a gas turbine engine having at least one compressor stage in which a numerical model is formed, said method comprising the steps of: generating said numerical model having numerical values that represent the compressor having a symmetrical geometry; superimposing a variation to said numerical values that represent said compressor with a symmetrical geometry in order to represent a compressor with an asymmetrical geometry; computing the evolution of the compressor with said asymmetric geometry and determining whether a rotating stall has occurred; repeating the above step until a rotating stall occurs; and then analyzing the circumstances that triggered said rotating stall.