Abstract: An algorithm for calculating the determining euations associated with non-classical method of symmetry reductions for system of partial differential euations (PDEs) is described.Based on this algorithm, an implementation bf NGDS on Maple for generating the determining euations for Lie non-classical symmetry groups of differential euation(s) is presented, and an example is illustrated the correctness and effectiveness of our package bf NGDS.

Key words: nonclassic symmetry, Lie group, symbolic computation, differential euations, nonclassic symmetry, Lie group, symbolic computation