Optimizer Doubts

Question

Hi experts,
We are working with Characteristic depending planning (CDP) together with setup matrixes based on characteristics.
First, we run an heuristic process that organizes the operation sequence .This is followed by the optimizer execution. The optimizer run lasts 5 minutes. However, the results obtained are not adjusted to the ones suggested by the matrix.
Unfortunately after the optimizer run, a manual adjustment must be done followed by a next run. This activity must be iterated until the desired result is reached.
I need some advise cause I need to clarify some doubts.
-Are the optimization results linked to the execution duration?
- Is it usual to make manual adjustments?
Regards,
Analía Nahmías

Answer 1

the optimizer results are of course linked to the calculation duration. the longer the better the results. you can enter a maximum run time in the optimizer profile.
general recommendation: 500 activities = 1 minute
if you increase this the optimzer will create more iterations and will get closer to the objective functions minimum.
it is unusual to adjust optiimizer results manually because any manual interaction destroys the optimizer result. it is like scales which have been delicately balanced with a lot of small weights on both sides. if you manually move one small weight to the other side the scale is out of balance.
If you work with set up matrices I recommend to check the set up costs and times of the transitions again. this is what the optimizer uses to schedule the activities.
for the optimizer, setup times and costs from the setup matrix are interpreted as follows:
in objective function:
     setup costs = 10 is comparable to a setup time of 10 seconds
     setup costs = 1000 is comparable to a setup time of 16 minutes
Use grouping functionality in the setup maintenance to group setup keys: Define setup groups and setup keys.
Do not just put everything in one big setup matrix using only individual setup keys.