Operations Research topics: SAS/OR,
SAS Optimization, and SAS Simulation Studio

Error:the nlp solver does not allow integer variables

Reply
New Contributor
Posts: 4

Error:the nlp solver does not allow integer variables

[ Edited ]

 

 

 

SAS Employee
Posts: 448

Re: Error:the nlp solver does not allow integer variables

Your Trigger constraint contains a product of decision variables and hence is nonlinear.  Also, it is redundant because the left hand side is a sum of nonnegative summands.  If you remove this constraint, the MILP solver will return an optimal solution with InspectDecision[j] = 0 for all j.

 

What logical condition on the other decision variables do you want to force InspectDecision[j] = 1?

New Contributor
Posts: 4

Re: Error:the nlp solver does not allow integer variables

I wanted to enfore that the trigger was 1 and multipled by the fixed cost for any of the Ts facilities that received any shipments at all. 

SAS Employee
Posts: 448

Re: Error:the nlp solver does not allow integer variables

In other words, you want inflow[i,j] > 0 to force InspectDecision[j] = 1.  Hint: You can do that by introducing InspectDecision[j] into the xMaxP constraint while keeping that constraint linear.

 

New Contributor
Posts: 4

Re: Error:the nlp solver does not allow integer variables

I figured it out, thank you so much for your help

Respected Advisor
Posts: 4,747

Re: Error:the nlp solver does not allow integer variables

@m3lon00, did you purposely delete your question statement?

PG
Ask a Question
Discussion stats
  • 5 replies
  • 395 views
  • 0 likes
  • 3 in conversation