Unread Parameter in AIMMS

Question

Hello, I have a question regarding AIMMS. I plan to do lab scheduling that will assign classes to a lab venue at a time. Each class will be taught by a different demonstrator, which I already specified in the parameter (Demo_Lab) as shown in the picture. However, whenever I included it in a constraint named Demo_Gap with an index domain (l,t), AIMMS did not follow the Demo_Lab parameter. AIMMS gave the results with a demonstrator randomly assigned to any class (you can refer to the final image). May I know how this is possible to happen?

The result shows AIMMS just assign demo to any classes without consider the mentioned parameter

Marcel Hunting · Accepted Answer

Hi@sarah rohaizad. IfDemo_Lab(c,l) equals 0 thenX(c,l,t,v) andX(c,l,t+1,v) will not be included in theDemo_Gapconstraint and therefore they will not be limited/restricted by this constraint. In other words, theDemo_Gapconstraint only defines a limitation/restriction for those X(c,l,t,v) for whichDemo_Lab(c,l) equals 1.Please note that if you want X(c,l,t,v) to be 0 wheneverDemo_Lab(c,l) equals 0 then you could change the index domain of the variable X(c,l,t,v) into:(c,l,t,v) |Demo_Lab(c,l) . (But your constraint AssignDemo already enforces X(c,l,t,v) to be 0 wheneverDemo_Lab(c,l) equals 0.)

sarah rohaizad · Answer

Since AIMMS could not read the Demo_Lab parameter in Demo_Gap constraint, I added one more constraint which shown below. Then, only AIMMS could read the parameter and gave the results like I intended to do.

Unread Parameter in AIMMS

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