Microsoft Office Tutorials and References

In Depth Information

**Saving and reusing the Solver parameters**

TROUBLESHOOTING

The Solver can’t solve my problem

The Solver is powerful but not miraculous. It might not be able to solve every problem

you give it. This is not always because the problem cannot be solved; sometimes it is

because you need to provide better starting parameters. If the Solver can’t find the

optimal solution to your problem, it presents an unsuccessful completion message in

the Solver Results dialog box. The most common unsuccessful completion messages

are the following:

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Solver could not find a feasible solution The Solver is unable to find a

solution that satisfies all your constraints. This can happen if the constraints are

logically conflicting or if not all the constraints can be satisfied (for example, if you

insist that your advertising campaign reach 800 million readers on a $1 million

budget). In some cases, the Solver also returns this message if the starting values

of your variable cells are too far from their optimal values. If you think your

constraints are logically consistent and your problem is solvable, try changing your

starting values and rerunning the Solver.

The maximum iteration limit was reached; continue anyway? To avoid

tying up your computer indefinitely with an unsolvable problem, the Solver is

designed to pause and present this message after it has performed its default

number of iterations without arriving at a solution. If you see this message, you

can resume the search for a solution by clicking Continue, or you can quit by

clicking Stop. If you click Continue, the Solver begins solving again and does not

stop until it finds a solution, gives up, or reaches its maximum time limit. If your

problems frequently exceed the iteration limit, you can increase the default

iteration setting by clicking the Solver button on the Data tab, clicking the Options

button, and typing a new value in the Iterations box.

●

The maximum time limit was reached; continue anyway? This message is

similar to the iteration-limit message. The Solver is designed to pause after a default

time period has elapsed. You can increase this default by choosing the Solver

command, clicking Options, and modifying the Max Time value.

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