As shown in Figure 2, the situation is slightly
more complex for constrained
optimization problems. The presence of a constraint boundary, in
Figure 2 in the form of a simple bound on the permitted
values of the control variable, can cause the global
minimum to be an extreme
value, an * extremum* (i.e., an endpoint), rather than a true stationary
point. Some methods of treating constraints transform the
optimization problem into an equivalent unconstrained one, with a
different objective function. Such techniques are discussed in
Section .

Figure 2: Types of Minima for Constrained Optimization Problems.