Example

• Program:

    
    q([],[]). 
    q([H|T],[X|Y]):- X is H + 1, q(T,Y).

• Cost function: .

• Parallel goal: ..., q(X,Y) & r(X), ...

• Transformed into:

   ..., length(X, LX), 
        Cost_q is LX * 2 + 1, 
       (Cost_q > 15  ->  q(X,Y) & r(X) 
                       ; q(X,Y), r(X)), ...

• Two issues in Granularity Control:
  • Determining task costs and overheads.
  • Controlling parallelism using that information.