boolean constraints in solver

[ultros1234]

Hi all --

I'm trying to set up a complex Solver problem, and I ran into a brick wall.

Eighteen of the variable cells have a boolean constraint. Specifically, the value needs to be either $0 or >=$3000, unless another value two columns over <>0. For each row, I've made a boolean value with a formula like this in cell AJ4:
=OR(AH4>=3000,AF4<>0,AH4=0)

And then a master boolean value at the bottom, that is all 18 of the other booleans multiplied together. It equals 1 if all eighteen of them are true. Then I add that master boolean as a constraint in my solver.

If all the values begin as true, the solver works fine. If any of them are false, it tells me "Solver encountered an error value in the Objective Cell or a Constraint cell. One of the cells in the worksheet became an error value when Solver tried certain values for the Variable cells."

It seems to me that Solver has a hard time parsing this kind of logical expression, which is too complex to put into one mathematical constraint.

Has anyone encountered this problem, and do you know a workaround?

Thanks!

 

[NARAYANK991]

Hi ,

Have you gone through this ?

http://www.solver.com/excel-solver-...ror-value-objective-cell-or-constraint-cell-9

Narayan

 

[ultros1234]

There are no error values in any of the cells.

Forgot to mention: using GRG Non-linear solving.

 

[NARAYANK991]

Hi ,

If you can upload your workbook with enough data in it , it may make it easier to resolve your problem.

Narayan

 

[ultros1234]

Okay, attached.

Just to be clear, the sticky wicket is that the values in column AH must be either 0 or >=3000, unless there's a non-zero value in column AF already. The constraint AJ28=1 is the problem. Change one of the AH variable values such that AJ28<>1, and the solver will fail.