Restricting variable to multiple values

[Martin]

I'm working on a container loading problem and I want to restrict the coordinates (x, y, z) of the edge of a bin to multiple values. These values are multiples of the length/width/heights of the bins. For example x-coordanite can only be 0, 10, 25, 30, 35, 40, 45, 50. But I want to this in a more general way, because I want to this for different combinations of bins.

See here the mathematical expression for the sets with the multiple values (l is length, w is width, h is height, b is an upper bound, m the number of bins)

Has anyone an idea how I can generate the sets X,Y and Z? And how can I restrict a variable to these sets (by definition or by constraint)? I couldn`t find anything in the group.

[Marcel Hunting]

Hi,

You can find an answer in this topic.

Best regards,

Marcel Hunting

AIMMS Optimization Specialist

[Martin]

Thanks a lot.

I implemented it with additional binary variables. But it is slower than the version with continous variables. 

So, there is no direct implementation of  several integer values for a variable in AIMMS?

[Marcel Hunting]

No, there is no direct way to implement this in AIMMS, and even if it would exist then AIMMS would have to introduce binary variables underneath. Again the problem would be harder to solve than the continuous version.

Marcel