Hi,
I'm modelling a problem where I need to make several products with different
specifications. Each product undergoes several unit operations where
ingredients are added.
var ingredient_used {Products, Unit_operations,Ingredients} >= 0;
Each ingredient has a cost and the total cost is to be minimized:
minimize total_cost: sum{p in Products,u in Unit_operations, i in Ingredients}
cost[i] * ingredient_used [p,u,i];
Each ingredient consists of several elements in different concentrations. Each
of the products has an aim value for concentration of each of the elements in
the product:
Subject to {p in Products, e in Elements}: sum {u in Unit_operations, i in
Ingredients} (ingredient_used [p,u,i]*concentration[i,e]) = aim[p,e];
This problem I can model and solve, but I need to add some more constraints.
One constraint is that there is a maximum number of ingredients that can be
kept in stock at a given unit operation. As an example, at the first unit
operation, I cannot keep more than 10 ingredients in stock, but the amount per
ingredient is unlimited.
How could I translate this into a mathprog constraint?
Regards,
Wouter
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