Adjustable Cell Ranges
Figure 1 - Adjustable Cell Ranges Window
The Adjustable Cell Ranges table displays each range of adjustable cells in a model; at least one adjustable cell range must be specified in an Evolver model and a model will always include at least one Group (for at least the single adjustable cell range). Each Group utilizes its own Solving Method. Additional adjustable cell ranges can be included and added to the single group, or to additional adjustable groups. See Adjustable Cell Group for more information.
All cell ranges in an Adjustable Cell Group share a common solving method; if the Genetic Algorithm is used, they also share the crossover rate, mutation rate, and operators.
Because the adjustable cells contain the decision variables of the problem, at least one group of adjustable cells must be defined. Most problems will be described with only one group of adjustable cells, but more complex problems can require different blocks of variables to be solved with different solving methods simultaneously. This unique architecture allows for highly complex problems to be built up from multiple groups of adjustable cells.
To add a new adjustable cell range, click the Add button, select a range of cells and click OK.
To delete an adjustable cell range, check the box to the left of its Range and click Delete.
The following options are available for entering Adjustable Cell Ranges:
- Check box - Each adjustable cell range has a check box to its left. Activate or deactivate any (or all) of the current adjustable cell ranges by checking or unchecking its box.
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Deactivating an adjustable cell range will remove it from the optimization, but will not delete it!
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Checking the box beside an adjustable cell range does NOT select it when using the Delete button or when editing Groups.
To select an adjustable cell range, click anywhere inside the row. The entire row will be highlighted.
- Range - The range specified is in the Range field. This can be changed if necessary by typing or pointing to a new range.
- Minimum and Maximum - Only available for Budget and Recipe solving methods. The Minimum and Maximum entries set the range of acceptable values for each adjustable cell in the range. These values are required.
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The Minimum and Maximum fields can contain either static values or cell references.
Additionally, the range can be set to greater-than/less-than or greater-than-or-equal/less-than-or-equal to the Minimum and Maximum values by clicking on the operator and using the pulldown menu (
).To use a static value, click inside the field and enter the value.
To use a cell reference, click the Select Cell button (
) to the right of the field. -
Evolver will not allow any values outside the specified ranges (unless soft constraints are specified). In cases where natural limits don’t exist (or aren’t known), limits should be set wide enough to allow all reasonable solutions, but the tighter these limits are kept, the quicker the solution process will run, as tighter limits restrict the scope of the search.
- Values - Only available for the Budget and Recipe solving methods. The Values entry specifies the type of adjustable cell values through which Evolver will search. In each of these settings, only values between the specified minimum and the specified maximum are included in the search.
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Figure 2 - Adjustable Cell Values Window
To set values for an adjustable cell range click the pulldown button (
) to open the Adjustable Cell Values window (Figure 2, right).
This window has the following options:
The default is to include all real numbers in the specified range. The use of Discrete (or Integer) values can dramatically decrease the number of possible solutions and will often result in much faster optimizations.