Difference: TransportationProblemInAMPL (5 vs. 6)

Revision 62008-04-02 - MichaelOSullivan

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META TOPICPARENT name="AMPLGuide"

The Transportation Problem in AMPL

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  >= Lower[i, j], <= Upper[i, j], integer;
Added:
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Also, since some arcs no longer exist you should set a default of 0 for Cost (thus you don't have to define costs for non-existent arcs).
param Cost {SUPPLY_NODES, DEMAND_NODES} default 0;
 

Balancing Transportation Problems

Balanced transportation models are preferred as there is no confusion about the relational operators for the supply and demand constraints. We can use a script file (transportation.run) to balance any transportation problem automatically:

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Changed:
<
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META FILEATTACHMENT attachment="transportation.mod" attr="" comment="" date="1207132918" name="transportation.mod" path="transportation.mod" size="1228" stream="transportation.mod" tmpFilename="" user="MichaelOSullivan" version="1"
>
>
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META FILEATTACHMENT attachment="transportation.run" attr="" comment="" date="1207132942" name="transportation.run" path="transportation.run" size="887" stream="transportation.run" tmpFilename="" user="MichaelOSullivan" version="1"
 
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