A solver is the actual FEM solver. It is based on the linear resolution of shift vectors, using a load vector and the inversion of stiffness matrix. This is typically a matrix and vectors in the orders of thousands of elements. A high number of solvers can also handle solutions in the field of non-linear behaviour of a system such as big deformations, contact convergence solutions and non-linear material model solutions.

As a rule, either an iteration process for resolving equations is used, the so called implicit method, or an explicit expression, especially for fast dynamic phenomena. These analyses may be very demanding in terms of the duration of the analysis run, which is why a high number of processor cores or computers grouped into computational clusters is used. The evolution of the solution can be tracked in a log file, or you can view the already converted steps of the non-linear analysis in a postprocessor.