Today I got a question on support whether the unit of a constraint influences the shadowprice; for instance, what is the consequence of using [ton] instead of [kg] on the unit of constraint for the shadowprice.
A small example illustrates the effects:
Variable x {
Range: free;
Unit: kg;
}
Constraint limX {
Unit: ton;
Property: ShadowPrice;
Definition: x <= 5:kg];
}
Variable o {
Range: free;
Unit: kg;
Definition: x;
}
The base unit of Mass is kg.
Running the model, the shadowprice returned for limX was 1; indicating that increasing the rhs by 1 unit (kg), will increase the objective by 1.
Then I changed the unit of limX to ton, and solved the model again.
The shadowprice returned was 1000; indicating that increasing the rhs by1 unit (ton), increased the objective by 1000.