Count and Ratio Constraints
An optimization model is a representation of the reality and the goal is to get it as close as possible, while ignoring as many details as you can. One of the specific business rules that can not always be ignored are constraints with respect to certain counts and ratios. For instance, each of my products can only be stored in 3 warehouses or 50% of my supply needs to be sourced from Europe. In the upcoming releases, we will gradually add some count and ratio constraints to the model.
In the rest of section, you see the constraints that are available already and that are coming in the upcoming releases.
Count Constraints
These constraints can be used to model business rules that impose minimum/maximum restrictions on the number of resources or locations that can be opened. SC Navigator currently contains the following new count constraint (see attribute details at Count Constraint Attributes):
Location Product: Enforces a constraint for the minimum/maximum number of locations (from a given group of locations) where at least one product (or product from a given product group) is active.
Resource Count: The minimum/maximum number of locations (from a given location group) where at least one resource (from a given resource group) is active.
The following count constraints will be available in future versions of SC Navigator (the attributes Minimum # of Source/Destination Locations are already captured by the model, see Optimization Parameters and Constraints):
Minimum # of Source Locations: Enforce a minimum number of source locations per product and period that can serve a customer or warehouse/production facility;
Minimum # of Destination Locations: - Enforce a minimum number of destination locations per product and period that the supplier/production/warehouse facility can serve;
Minimum/Maximum Inflow from Source Locations: - Enforce a minimum/maximum number of products that may be sent from a source location to a customer or production/warehouse location;
Minimum/Maximum Outflow to Destination Locations: - enforce a minimum/maximum number of products that can be sent from a supplier/production/warehouse location to a destination location.
Ratio Constraints
These constraints can be used to model business rules that impose restrictions on the contribution that should be made by certain suppliers or resources. For example, it may be important that no supplier is responsible for providing more than x % of a raw material, or road transport cannot exceed y % of total transportation between two locations or location groups.
The following ratio constraints will be available in future versions of SC Navigator:
Transport Ratio: Enforcing transport lanes to carry a particular ratio of the total in/out flow for locations or resources. For instance, inbound transport to a DC must be at least 70% road and 30% rail;
Base Case Ratio: Keep all in/out flow ratios consistent with the base case, that is, model a projected baseline by ensuring that the ratio of supply, production, and throughput change with a ratio that is consistent with the base case;
Supplier Ratio: Enforce a minimum and maximum ratio of the contribution of a supplier or supplier group with respect to the total supply;
Production Ratio: Enforce a minimum and maximum ratio with respect to the total production amount for a production resource, or a group of productions;
Warehouse Ratio: Enforce a minimum and maximum ratio with respect to the throughput, inflow, and outflow for a warehouse, or a group of warehouses;
Minimum/Maximum Ratio of Source Locations: Enforce a minimum/maximum ratio of products that may be sent to a customer or production/warehouse facility from a source location, with respect to the total inflow at the given customer or facility;
Minimum/Maximum Ratio of Destination Locations: Enforce a minimum/maximum ratio of products that may be sent from a production/warehouse facility from a customer or another facility, with respect to the total outflow from the given facility.