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