ILOG CPLEX's Primal Simplex Optimizer also can effectively solve a wide variety of linear programming problems with its default parameter settings. The primal simplex method is not the obvious choice for a first try at optimizing a linear programming problem. However, this method will sometimes work better on problems where the number of variables exceeds the number of constraints significantly, or on problems that exhibit little variability in the cost coefficients. Few problems exhibit poor numeric performance in both primal and dual form. Consequently, if you have a problem where numeric difficulties occur when you use the dual simplex optimizer, then consider using the primal simplex optimizer instead.