Aspen SCM‎ > ‎

SCM Planning

SCM Planning (also known as MIMI/LP)  is the module in Aspen SCM which allows you to build models based on Linear Programming (LP). Such models are typically used in planning and scheduling, hence the name of the module.

Aspen SCM Planning differs from other LP modelling packages by being integrated into the Aspen SCM toolkit. It is designed to provide part of a complete solution rather than a solution in its own right. This reflects the origins of SCM Planning in oil refineries: LP models are very good for modelling continuous processes with many options. While to a first approximation this describes an oil refinery, in reality an oil refinery is a mix of continuous and batch processes. To run an oil refinery you need a detailed schedule of the batch processes as well as an overall plan. By integrating LP with other tools, Aspen SCM  supports the development of models which tackle both planning and scheduling.

Aspen SCM Planning is a general-purpose tool which allows you to build any LP model. It also supports extensions to LP, notably Mixed Integer Programming (MIP) and Successive Linear Programming (SLP).

Aspen SCM Planning uses a series of standard sets and tables to define an LP model. You build an LP model by configuring these sets and tables and setting up your own sets and tables which these standard ones reference. You run the LP model from a rule or a macro by executing the GEN command followed by OPT. The results are stored in some other standard tables, which your code then reads before continuing its processing. In this way the LP model is in effect a subroutine which your program calls.

The pages beneath this one explain how to convert a mathematical formulation into the tables which Aspen SCM Planning uses.

1. Required Sets and Tables
2. Implementing a Mathematical Formulation
3. Generic Rows and Columns
4. How the Matrix is Generated
5. Policies
6. Families of Sets and the No-match Flag
7. Representing Multiple Terms for a Decision Variable in a Constraint