solver :: Solver
solver = ipoptSolver { options = [ ("expand", GBool True)
                                 --, ("ipopt.linear_solver", GString "ma86")
                                 --, ("ipopt.ma86_order", GString "metis")
                                 , ("ipopt.tol", GDouble 1e-11)
                                 ] }
solver :: Solver
solver = ipoptSolver { options = [ ("expand", GBool True)
                                 --, ("ipopt.linear_solver", GString "ma86")
                                 --, ("ipopt.ma86_order", GString "metis")
                                 , ("ipopt.tol", GDouble 1e-11)
                                 ] }
solver = ipoptSolver { options = [ ("expand", GBool True)
                                 --, ("ipopt.linear_solver", GString "ma86")
                                 --, ("ipopt.ma86_order", GString "metis")
                                 , ("ipopt.tol", GDouble 1e-11)
                                 ] }