The Eigenvalue Problem Solver (EPS) is the object provided by SLEPc for specifying a linear eigenvalue problem, either in standard or generalized form. It provides uniform and efficient access to all of the linear eigensolvers included in the package.
EPS users can set various options at runtime via the options database (e.g., -eps_nev 4 -eps_type arnoldi).
Options can also be set directly in application codes by calling the corresponding routines (e.g., EPSSetDimensions() / EPSSetType()).