Implicit Non-Negativity Constraints

Many Solver problems -- and perhaps most LP problems -- have "non-negativity" constraints, or lower bounds of zero on the decision variables. To save you the trouble of entering these constraints explicitly in the Constraints list box, the Solver provides an Assume Non-Negative check box in the Solver Options dialog. When this box is checked, all variables which do not have explicit lower bounds in the Constraint list box are automatically given lower bounds of zero. You can enter constraints such as A1 >= 2 or A1 >= -3 for certain variables, overriding the implicit lower bound, and check the Assume Non-Negative box to give all other variables a lower bound of zero.