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Solver.com
From Frontline Systems, developers of the Excel Solver.
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Troop Movement |
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| An
army wants to move troops from 3 training camps to 4 different bases. How
should |
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minimize cost? |
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| Moving Cost Per Man |
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Base 1 |
Base 2 |
Base 3 |
Base 4 |
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| Camp 1 |
$34 |
$26 |
$29 |
$31 |
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| Camp 2 |
$42 |
$33 |
$28 |
$35 |
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| Camp 3 |
$36 |
$29 |
$32 |
$38 |
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| Number Of Troops Moved |
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Base 1 |
Base 2 |
Base 3 |
Base 4 |
Total |
Available |
| Camp 1 |
100 |
100 |
100 |
100 |
400 |
500 |
| Camp 2 |
100 |
100 |
100 |
100 |
400 |
400 |
| Camp 3 |
100 |
100 |
100 |
100 |
400 |
400 |
| Total |
300 |
300 |
300 |
300 |
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| Required |
200 |
250 |
350 |
300 |
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| Cost |
$11,200 |
$8,800 |
$8,900 |
$10,400 |
$39,300 |
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| Problem |
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| An
army wants to move troops from 3 training camps to 4 different bases. All
costs of moving a |
| soldier from any camp to any base are known. How should the
army move the troops to |
| minimize cost? |
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| Solution |
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| 1)
The variables are the number of soldiers that are moved from each camp to
each base. On |
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Troops these are given the name Troops_moved. |
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| 2) The
constraints are |
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Troops_moved >= 0 via the Assume Non-Negative option |
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Troops_per_camp <= Troops_available |
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Troops_per_base = Troops_required |
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| 3) The objective is to minimize the total cost. This is
defined on the worksheet as Total_cost. |
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| Remarks |
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| This
model is a transportation model, like those shown in the Logistics Examples
workbook. You |
| might wonder why there is no constraint to assure that the
numbers of troops moved are integers. |
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is a mathematical property of these types of problems that if the constants
in the constraints are |
| integers,
the solution values for the variables are always integers. It is beyond the
scope of these |
| examples to
further explore this. |
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