Excel Solver and VBA: Floating point/decimal numbers in constraints get incorrectly converted to integers?

Question

I'm running VBA scripts under both Excel 2007 and 2010 which involve a lot of optimization using the built-in Solver of Excel.

What is the correct way to specify decimal constraints like X>=0.0001 where X would be the decision variable of the problem.

SolverAdd CellRef:=cells(5,5), Relation:=3, FormulaText:="0.0001"

Or do I have to remove the quotes " " ? And does the VBA interface of Solver allow for decimal (non-integer) constraints anyway?

I'm asking, because sometimes I get the (unconfirmed) feeling that a constraint of >=0.0001 is incorrectly interpreted as >=1, which of course renders wrong results.

It would be great if somebody could clarify these issues for me.

Steve

Answer 1

We've found that FormulaText can really effect the final solution. We've always just used straight numbers there, no quotes:

SolverAdd CellRef:=cells(5,5), Relation:=3, FormulaText:=0.0001