* linear problem (lp)

* mixed-integer linear problem (milp)

* quadratic problem (qp)

* non-linear problem (nlp)

* non-smooth problem (nsp)

* non-linear solve problem (nlsp)

* least squares problem (lsp)

* linear least squares problem (llsp)

* mini-max problem (mmp)

* global problem (glp)

a variety of solvers is available (e.g. ipopt, algencan).