Increasing of efficiency of the finite-element shemes for solving induction aerial prospecting three-dimensional tasks

Research carried out on an example of aerial prospecting by electric methods problem solving has allowed to make the following conclusions. Best on calculation time expenditures are GMRES and schemes using preconditioning with block-elements of type lu38. The application of lu26-type blocks allows noticeably reduced memory requirements, but increase of calculation time. We note that preconditioned GMRES with the block of type lu26 and depth 10 practically coincides memory expenditures with preconditioned scheme with the lu38-type block, but considerably behind it on time. Advantages are especially great if only diagonal blocks of a matrix P decomposition is used. In this case memory expenditures differ almost of an order. Using such preconditions is extremely disadvantageous to calculation time; however in conditions of memory deficiency such methods can uniquely obtain solutions on a detailed finite-element mesh