Description of the problem
Includes what to do and where to find the files.
The problem is to plan the blending of five kinds of oil, organized in two categories (two kinds of vegetable oils and three kinds of non vegetable oils) into batches of blended products over six months.
Some of the oil is already available in storage. There is an initial stock of oil of 500 tons of each raw type when planning begins. An equal stock should exist in storage at the end of the plan. Up to 1000 tons of each type of raw oil can be stored each month for later use. The price for storage of raw oils is 5 monetary units per ton. Refined oil cannot be stored. The blended product cannot be stored either.
The rest of the oil (that is, any not available in storage) must be bought in quantities to meet the blending requirements. The price of each kind of oil varies over the six-month period. The two categories of oil cannot be refined on the same production line.
There is a limit on how much oil of each category (vegetable or non vegetable) can be refined in a given month:
Not more than 200 tons of vegetable oil can be refined per month.
Not more than 250 tons of non vegetable oil can be refined per month.
There are constraints on the blending of oils:
The product cannot blend more than three oils.
When a given type of oil is blended into the product, at least 20 tons of that type must be used.
If either vegetable oil 1 (v1) or vegetable oil 2 (v2) is blended in the product, then non vegetable oil 3 (o3) must also be blended in that product.
The final product (refined and blended) sells for a known price: 150 monetary units per ton.
The aim of the six-month plan is to minimize production and storage costs while maximizing profit.
What you are going to do
The example used is a standard industrial problem of food manufacturing as formulated by H.P. Williams (food manufacturing 2 in Model Building in Mathematical Programming). The aim of the problem is to blend a number of oils cost effectively in monthly batches. In this form of the problem, the number of ingredients in a blend must be limited, and extra conditions are added to govern which oils can be blended.
Where to find the files
The food manufacturing example is supplied as the foodmanufact example
at the following location:
<Install_dir>\opl\examples\opl\foodmanufact
where <Install_dir> is
your installation directory.