If the Quadratic Recognition box is checked, LINGO will use algebraic preprocessing to determine if an arbitrary nonlinear model is actually a quadratic programming (QP) model. If a model is found to be a QP model and convex, then it can be passed to the faster quadratic solver.  Note that the QP solver is not included with the standard, basic version of LINGO, but comes as part of the Barrier option.

LINGO defaults to using quadratic recognition.