Reasons for Infeasibility

The TRANS Procedure

Reasons for Infeasibility

By default, PROC TRANS assumes that all transportation problems have total supply equal to total demand. The THRUNET and NOTHRUNET options enable you to relax this assumption.

A transportation problem is infeasible if nodal flow conservation constraints cannot be met so that the flow into a node plus its supply does not equal the flow out of the node plus its demand. Instances of this type of infeasibility occur when

the supply of a source node exceeds the total capacities of arcs leading out of it
the supply of a source node does not meet the total lower flow bounds of arcs leading out of it
the demand of a sink node exceeds the total capacities of arcs leading into it
the demand of a sink node does not meet the total lower flow bounds of arcs leading into it

If a solution does not exist where all arcs have flow on or between their lower flow bounds or capacities, the problem is infeasible.

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