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answer-set-programmingclingo

Differences in optimization statement syntax (clingo 3 and clingo 4)

I have an optimization statement in a logic program, for clingo3:

#minimize [ batteryFlat(mycar)=1, batteryFlat(yourcar)=1, hasNoFuel(mycar)=1, 
    hasNoFuel(yourcar)=1, brokenIndicator(mycar)=1, brokenIndicator(yourcar)=1].

(Basically, I want the solution to contain as few of the above as possible - they are all of equal weight).

This syntax works for clingo3, but not clingo4. How should it be re-written for clingo4?

Solution

  • How about this:

    #minimize {batteryFlat(mycar); batteryFlat(yourcar); hasNoFuel(mycar); 
hasNoFuel(yourcar); brokenIndicator(mycar); brokenIndicator(yourcar)}.

    The set is now separated with ; and you can then use , to conjoin conditions. Each element has the same priority, but if you want different priorities you can do something like:

    #minimize {1@1: batteryFlat(mycar); 1@2: batteryFlat(yourcar); hasNoFuel(mycar); 
hasNoFuel(yourcar); brokenIndicator(mycar); brokenIndicator(yourcar)}.

    Now the first atom has priority one (for at least one occurrence, I think) and the second atom a higher priority.

    Or, if you have variables give priority to the number of different groundings like so:

    #minimize {X@1: batteryFlat(X); 1@2: batteryFlat(yourcar); hasNoFuel(mycar); 
hasNoFuel(yourcar); brokenIndicator(mycar); brokenIndicator(yourcar)}.

    Comparisons are shown here: http://sourceforge.net/projects/potassco/files/clingo/4.2.0/