Difference: ObjectiveFunctionsInAMPL ( vs. 1)

Revision 12008-03-02 - MichaelOSullivan

Line: 1 to 1
<-- Ready to Review -->

Objective Functions in AMPL

  1. Description
  2. Declaring an Objective Function
  3. Defining an Objective Function


The objective function of a mathematical programme is a function of the decision variables that measures the "worth" of the decisions. This "worth" is being either maximised or minimised (although, if no objective function is defined, AMPL will use the solver to search for a feasible solution).

Return to top

Declaring an Objective Function

Objective functions are declared using either the minimize or maximize keyword and a label:

minimize TotalCost;

Return to top

Defining an Objective Function

Objective functions are usually defined when they are declared, e.g.,

minimize TotalCost: sum {i in INGREDIENTS} Cost[i] * Amount[i];

However, in some cases (such as when models are defined by column), the objective function is defined later

minimize TotalWorkers;

var Work {j in SCHEDS} >= 0, integer,
  obj TotalWorkers 1,

Return to top

-- MichaelOSullivan - 02 Mar 2008

This site is powered by the TWiki collaboration platform Powered by PerlCopyright © 2008-2020 by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding TWiki? Send feedback