Constraint Left and Right Hand Sides
The constraint left hand side, entered in the Cell Reference edit box, may be any cell range,
such as a column, row, or rectangular area of cells. The cells you reference must
be on the active worksheet. In the example shown earlier, we could have
entered all five constraint left hand sides at once, as B1..B5 (as long as we
entered the five right hand sides at the same time).
The constraint right hand side may be any of the following:
1. A numeric constant such as 1.
2. A cell reference such as C1.
3. A cell range such as C1..C5.
4. An arbitrary formula such as +A:C1+1 or +A:C2/B:D2.
5. Either "integer" or "binary" for integer constraints
Option 5 is for integer constraints only and is discussed below under "Using Integer Constraints." When entering a
formula (Option 4), be sure to include an explicit sheet reference such as A:C1.
This is the only context where you can refer to cells on sheets other than the
active worksheet. If you use option 3 -- a selection of more than one cell --
the number of cells selected must match the number of cells you selected for
the constraint left hand side. The two selections need not have the same
"shape:" For example, the left hand side could be a column and the right hand side a
row. You may also use rectangular areas of cells. In any case, when you use
this form you are specifying several constraints at once, and the constraint
left hand sides correspond element-by-element to the right hand sides. In the
example shown earlier, you could have entered the right hand side values 400, 200,
800, 400 and 600 into cells C1 to C5, and entered a single constraint such as
B1..B5 <= C1..C5. You can see examples of this form in nearly all of the
sample worksheets included with the Solver, as well as throughout this Helpfile. It
is by far the most useful form.
If the constraint right hand side is a cell reference, cell selection or
formula, the Solver needs to know whether the contents of those cells, or the value
of the formula is constant in the problem, or variable (i.e. dependent on the values of the decision variables). If the right hand
side depends on any of the decision variables, the Solver transforms a
constraint such as "LHS >= RHS" into "LHS - RHS >= 0" internally. Both the linear
and nonlinear Solvers work internally with constant bounds on the constraint
functions.