ObjectiveInstance

class ObjectiveInstance

The ObjectiveInstance object stores the information regarding a specific instance of an objective. The instances can be accessed through the function Objective.get of the parent entity.

value()

classmethod ObjectiveInstance.value()

Syntax

v = value()

Description

v = value() Get the current value of the objective instance

Output Arguments

v

The current value of the objective instance

Example

Create an indexed objective z, get an instance and display its value. Then solve the problem and display the value again.

ampl.eval('var x{i in 1..2} <= i;');
ampl.eval('maximize z{i in 1..2}: x[i];');
z = ampl.getObjective('z');
instance = z.get(1);
instance.value
ampl.solve;
instance.value

gives:

ans =
  0

ans =
  1

astatus

classmethod ObjectiveInstance.astatus()

Syntax

v = astatus

Description

astatus Return the AMPL status for this objective instance.

Output Arguments

v

The AMPL status for this objective instance.

Example

Create an indexed objective z, get an instance and display its status. Then solve the problem and display it again.

ampl.eval('var x{i in 1..2} <= i;');
ampl.eval('maximize z{i in 1..2}: x[i];');
z = ampl.getObjective('z');
instance = z.get(1);
instance.astatus
ampl.solve;
instance.astatus

gives:

ans =
in

ans =
in

exitcode

classmethod ObjectiveInstance.exitcode()

Syntax

v = exitcode

Description

exitcode Get exit code returned by solver after most recent solve with this objective.

Output Arguments

v

The exit code returned by solver after most recent solve with this objective.

Example

Create an indexed objective z, get an instance and display its exitcode. Then solve the problem and display it again.

ampl.eval('var x{i in 1..2} <= i;');
ampl.eval('maximize z{i in 1..2}: x[i];');
z = ampl.getObjective('z');
instance = z.get(1);
instance.exitcode
ampl.solve;
instance.exitcode

gives:

ans =
0

ans =
0

message

classmethod ObjectiveInstance.message()

Syntax

v = message

Description

message Get the result message returned by solver after most recent solve with this objective.

Output Arguments

v

The result message returned by solver after most recent solve with this objective

Example

Create an indexed objective z, get an instance and display the solver message. Then solve the problem and display it again.

ampl.eval('var x{i in 1..2} <= i;');
ampl.eval('maximize z{i in 1..2}: x[i];');
z = ampl.getObjective('z');
instance = z.get(1);
instance.message
ampl.solve;
instance.message

gives:

ans =
?

ans =
CBC 2.8.2 optimal, objective -1
0 iterations

result

classmethod ObjectiveInstance.result()

Syntax

v = result

Description

result Get the result string returned by solver after most recent solve with this objective.

Output Arguments

v

The result string returned by solver after most recent solve with this objective.

Example

Create an indexed objective z, get an instance and display its result string. Then solve the problem and display it again.

ampl.eval('var x{i in 1..2} <= i;');
ampl.eval('maximize z{i in 1..2}: x[i];');
z = ampl.getObjective('z');
instance = z.get(1);
instance.result
ampl.solve;
instance.result

gives:

ans =
?

ans =
solved