The goal of an optimization problem can be
formulated as follows: find the combination of parameters
(independent variables) which optimize a given quantity, possibly
subject to some restrictions on the allowed parameter ranges. The
quantity to be optimized (maximized or minimized) is termed the
* objective function*; the parameters which may be changed in the quest
for the optimum are called control or * decision variables*; the
restrictions on allowed parameter values are known as * constraints*.

A maximum of a function **f** is a minimum of **-f**. Thus, the general
optimization problem may be stated mathematically as:

where is the objective function, is
the column vector of the **n** independent variables, and
is the set of
constraint functions. Constraint equations of the form
are termed
* equality constraints*, and those of the form
are * inequality
constraints*. Taken together, and
are known as the * problem functions*.