I am having a non-linear optimization model with several variables and a certain function between three of them should be defined as a constraint. (Let us say, that the efficiency of a machine is dependent on the inlet and outlet temperatures). I have calculated some values in a table to visualize the dependency for T_inlets and T_outlets. It gives back a pretty ugly surface. A good fit would be something like a 5 degree polynomial equation if I wanted to define a function directly, but I do not think that would boost my computation speed... So instead I am considering simply having the created table and use it as a lookup table. Is a non-linear solver able to interpret this? I am using ipopt in Pyomo environment.
Another idea would be to limit my feasible temperature range and simplify the connection...maybe with using peace-wise linearization. Is it doable with 3d surfaces?
Thanks in advance!
