LP method used to solve sifting sub-problems. Options are Automatic (-1), Primal Simplex (0), Dual Simplex (1), and
Barrier (2). Note that this parameter only has an effect when you are using dual simplex and sifting has been selected
(either automatically by dual simplex, or through the `Sifting` parameter).

Changing the value of this parameter rarely produces a significant benefit.