http://quantlib.org/reference/class_quant_lib_1_1_m_c_discrete_arithmetic_a_p_engine.html
A sentence says that:Monte Carlo pricing engine for discrete arithmetic average price Asian options. It can use MCDiscreteGeometricAPEngine (Monte Carlo discrete arithmetic average price engine) and AnalyticDiscreteGeometricAveragePriceAsianEngine (analytic discrete arithmetic average price engine) for control variation. It means that the MCDiscreteGeometricAPEngine is a Monte Carlo discrete arithmetic average price?? arithmetic??AnalyticDiscreteGeometricAveragePriceAsianEngine (analytic discrete arithmetic average price engine)??arithmetic??