The program package for investigation of differential equations by the external form method

The algorithm to invesigate the symmetry properties of differential equation by the external form method and the corresponding code are presented. The code realises the algebra of differential forms and it is simple in use due to simplification of data input-output concerning the differential equation under investigation. As input the differential operator or the external form representation of initial equation may be used. The code is used to construct the system of determining equations which then is presented in a passive form. The symmetry group algebra for a given equation must be found by a user. The code usage is illustrated for a large amount of nonlinear equations such as Dirac equation, shallow water model equation, Prandtl equation and so on