Excel Solver - Binary Constraint Identified as Nonlinear

Question

Hello,

I am working on model that uses the Simplex LP engine.  The model has to be solved using Simplex LP.  I have a binary decision variable in the model that is listed in decision field and identified as binary in the constraint section. 

When I run the model I get an error message indicating that the binary decision cell is not linear.  The linearity report shows that the constraints linked to that cell are in fact linear.  The constraints are designed to give me a yes/no decisions after a certain point.   I am not sure why excel is not treating that cell as linear. 

The binary decision variable cell is the only one in the report that is listed as non-linear. 

Any help is greatly appreciated.

Answer 1

Hello Zixuan,

It was able to figure out what the issue was.  The Simplex Solver in MS Excel is not able to solve nested formulas that are tied to a binary constraint.  I was using the binary constraint to incorporate options into the model and to turn on additional calculations within the options that would run calculations if the model turned on that constraint.  Once I changed those nested formulas to once that are static verse dynamic the solver was able to optimize the model without any error.s 

Hope that helps.

FH

Answer 2

I have not used any discontinuous function like  IF.  The only complex function that is in the model is SUMPRODUCT.

Answer 3

Hi FH Yousif ,

LP Simplex is used for problems that are linear. According to the error, it may due to your decision. Could you please capture some screenshots for us to troubleshoot?

Moreover, please provide your Office version as well. (Open Excel>File>Account>Product Information)

Regards,

Zixuan

Answer 4

Hi FH Yousif,

Do you still experience the issue?

Please share the status at your convenience.

Regards,

Zixuan