Incorrect Slack Value Returned in Solver Answer Report (116390)
The information in this article applies to:
- Microsoft Excel for Windows 95 7.0a
- Microsoft Excel for Windows 5.0c
- Microsoft Excel for Windows 4.0a
- Microsoft Excel for the Macintosh 5.0a
- Microsoft Excel for the Macintosh 4.0
This article was previously published under Q116390 SYMPTOMS
In Microsoft Excel, when you use the Solver add-in to find a solution, and
you add a constraint that consists of one cell value that depends on
another cell value, the Slack value that appears in the Constraint table on
the Answer report for that cell is incorrect.
CAUSE
The slack value that appears on the Answer report when you use the
Solver add-in is the absolute value of the difference between the two
parts of a constraint. The left part of the constraint is the
constraint cell, while the right part of the constraint is the target
value for the constraint cell. When the right part of the constraint
is a constant, the reported Slack value is correct. However, when the
right part of the constraint can vary during the solving, the Slack
value is not calculated using the final value of the right part of
the constraint.
The following is an example of a constraint where the second part of
the constraint is a constant:
$A$1 <= 10
The following is an example of a constraint where the second part of
the constraint varies during the solving:
$A$1 <= $A$2
Using the constraint above, if the final value of the constraint cell
($A$1) is 5, and the final value of the target cell ($A$2) is 10, the
Slack value for the constraint cell A1 should be 5. However, when you
use Solver with a constraint such as this second example, the Slack
value for cell $A$1 is incorrect on the Answer report.
STATUS
Microsoft has confirmed this to be a problem in the Microsoft
products listed at the beginning of this article. We are researching
this problem and will post new information here in the Microsoft
Knowledge Base as it becomes available.
REFERENCES
For more information about Creating A Report Using Solver, choose the
Search button in Help and type:
| Modification Type: | Minor | Last Reviewed: | 8/15/2003 |
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| Keywords: | KB116390 |
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