I have problem with using piecewise fucntion in OPL langage. In fact, i use it to represent water flows in function of teh existing volume within an evacuator. I have three evacuators,and a 4-piece function for each evacuator (4 points to represent the graph). The obejctive of the problem i modelize is to opttimize the flows of water towards a hydroelectricty production plant. When i run the model for a small planning horizon (100 days), i obtain the optimal solution within about minutes. But when i use a 365 plannign horizon, Cplex is not able to give me the optimal solution and i get a memory-out-of order error within 5 minutes (i need absolutely teh optimal solution)
Is there an additional setup that i should consider to optimize the use of picewise fucntion?