Main

Objective Variables

Main.ObjectiveVariables History

Show minor edits - Show changes to output

April 02, 2017, at 05:50 PM by 45.56.3.173 -
Changed line 25 from:
This obtains the current objective function value. An objective may consist of multiple objectives that are maximized or minimized. They are all converted to minimization functions and added together.
to:
This obtains the current objective function value with input arguments ''s=server'' and ''a=application name''. An objective may consist of multiple objectives that are maximized or minimized. They are all converted to minimization functions and added together.
April 02, 2017, at 05:50 PM by 45.56.3.173 -
Changed lines 17-21 from:
The %blue%A%red%P%black%Monitor objective is reported in the minimized form. Thus, a maximized objective with a result of +17 is reported as -17. This is retrieved as the parameter ''nlc.objfcnval'' in a programming script from the ''apm_tag'' function such as:
to:
The %blue%A%red%P%black%Monitor objective is reported in the minimized form. Thus, a maximized objective with a result of +17 is reported as -17.

!!! Retrieve Objective Function

The objective function
is retrieved as the parameter ''nlc.objfcnval'' in a programming script from the ''apm_tag'' function such as:
April 02, 2017, at 05:46 PM by 45.56.3.173 -
Changed lines 7-8 from:
The objective function is always minimized with %blue%A%red%P%black%Monitor.  Objective function maximization is accomplished by defining a new variable that is the negative of the minimized objective.
to:
The objective function is always minimized with %blue%A%red%P%black%Monitor.  Maximizing an objective function is accomplished by minimizing the negative of the original objective.

 ! original objective
 maximize z

The
objective is modified by minimizing the negative of the original objective function.

 ! modified objective
 minimize -z

The %blue%A%red%P%black%Monitor objective is reported in the minimized form. Thus, a maximized objective with a result of +17 is reported as -17. This is retrieved as the parameter ''nlc.objfcnval'' in a programming script from the ''apm_tag'' function such as:

 obj = apm_tag(s,a,'nlc.objfcnval')

This obtains the current objective function value. An objective may consist of multiple objectives that are maximized or minimized. They are all converted to minimization functions and added together
.
Changed lines 27-41 from:
 ! Example model with an objective function
 Model example
   Parameters
 
  p1 = 5
 
  End Parameters

  Variables
     objective
    v1 > 6
  End Variables

  Equations
    objective = (v1 -
p1)^2
  End Equations
 End Model
to:
 ! Example model with an objective variable
 Parameters
 
  p1 = 5
 Variables
  objective
   v1 > 6
 Equations
  objective = (v1 - p1)^2
Changed lines 36-51 from:
to:
 ! Equivalent model with a minimize objective statement
 Parameters
  p1 = 5
 Variables
  v1 > 6
 Equations
  minimize (v1 - p1)^2
(:cellnr:)
 ! Equivalent model with a maximize objective statement
 Parameters
  p1 = 5
 Variables
  v1 > 6
 Equations
  maximize -(v1 - p1)^2
(:cellnr:)
Deleted line 55:
June 16, 2015, at 06:45 PM by 45.56.3.184 -
Deleted lines 0-1:
!! Objective Variables
June 16, 2015, at 06:45 PM by 45.56.3.184 -
Changed line 13 from:
(:table border=1 width=50% align=left bgcolor=#EEEEEE cellspacing=0:)
to:
(:table border=1 width=100% align=left bgcolor=#EEEEEE cellspacing=0:)
September 25, 2008, at 07:44 PM by 158.35.225.230 -
Changed lines 30-31 from:
to:
(:cellnr:)
Added line 36:
September 25, 2008, at 07:44 PM by 158.35.225.230 -
Added lines 1-36:
!! Objective Variables

Objective variables are defined to construct an objective function.  The objective function is a summation of all variables that are designated as objective-type.  Variables are defined as objective function contributions by starting with '''obj'''.  Thus, the variables ''obj1'', ''objective'', ''object[1]'' would be included in the objective function summation.

Additionally, slack variables are included in the objective function.  These variables begin with the key letters '''slk''' and are defined with a lower bound of zero.

!!! Minimize vs. Maximize

The objective function is always minimized with %blue%A%red%P%black%Monitor.  Objective function maximization is accomplished by defining a new variable that is the negative of the minimized objective.

!!! Example

(:table border=1 width=50% align=left bgcolor=#EEEEEE cellspacing=0:)
(:cellnr:)
 ! Example model with an objective function
 Model example
  Parameters
    p1 = 5
  End Parameters

  Variables
    objective
    v1 > 6
  End Variables

  Equations
    objective = (v1 - p1)^2
  End Equations
 End Model

 Solution
  p1 = 5
  v1 = 6
  objective = 1
(:tableend:)