Toyota manufactures cars by purchasing parts from different suppliers at different prices. The production process varies between different vehicle models, components and different factories. The company wants to optimize the weekly production schedule and manage the required stock of parts to maintain a certain stock level. There are 4 different components that Toyota will use for the cars it produces. These components are called A, B, C and D. For each of these components, they are available from different suppliers and can be purchased at different prices. Weekly stock levels of these components should also be determined. Each week, the minimum stock level of each component is specified to maintain a certain stock level. Also, the weekly production schedule should be divided among the factories that have a certain production capacity. Production constraints are minimum production quantities for each component. The production plan should be optimized to minimize both production costs and inventory costs.