TY JOUR TI Using free softwear for solving one problem of mathematical physics KW free software KW computer mathematics systems KW Laplace equation KW Dirichlet problem KW finite-difference method KW programming language KW boundary conditions KW method of successive over-relaxation JO Vestnik of Astrakhan State Technical University. Series: Management, computer science and informatics AU Martianova, A.E. PY 2020 IS PB Astrakhan State Technical University