What sort of problems can I solve using the eplex library?
The exact types of problems that can be solved depend on the solver that eplex is interfaced to. At the minimum, eplex should be able to solve linear problems (LP), and probably also mixed integer linear problems (MILP). In addition, eplex supports the specification of a quadratic objective function, so if supported by the solver, it can also solve quadratic problems (QP) and mixed integer quadratic problems (MIQP). Note that if you are using a commercial solver, your license may not permit you to solve all problem types, even if the solver supports it.