prologprolog-setof

Setof: Is there a way for early stopping?

I want to find the minimun number of errors for a lot of schedules. I produce a schedule, take it's errors, store all Errors in a list and take the first element(MinError). The MinError is >=0, so I wonder if I can stop this process when a random schedule get Errors=0 and return the MinError.

setof(Errors,A^B^C^(schedule(A,B,C),schedule_errors(A,B,C,Errors)),[MinError|_]).

Solution

  • You may use an if-then-else with a cut to stop processing further solutions when you found your minima:

    setof(Errors, 
      A^B^C^(
             schedule(A,B,C),
             schedule_errors(A,B,C,Errors),
             (Errors=0 -> ! ; true)
            ), 
      [MinError|_]).