12.07.2015 Views

ILOG CPLEX 11.0 User's Manual

ILOG CPLEX 11.0 User's Manual

ILOG CPLEX 11.0 User's Manual

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

20Using Indicator ConstraintsThis chapter introduces indicator constraints.◆ What Is an Indicator Constraint? on page 355◆ Example: fixnet.c on page 356◆ Indicator Constraints in the Interactive Optimizer on page 356◆ What Are Indicator Variables? on page 357◆ Restrictions on Indicator Constraints on page 357◆ Best Practices with Indicator Constraints on page 357What Is an Indicator Constraint?An indicator constraint is a way for a user of the Callable Library (C API) to expressrelationships among variables by identifying a binary variable to control whether or not aspecified linear constraint is active. This feature is also available in the InteractiveOptimizer, as explained in Indicator Constraints in the Interactive Optimizer on page 356.Formulations using indicator constraints can be more numerically robust and accurate thanconventional formulations involving so-called Big M data. Big M formulations use artificialdata to turn on or turn off enforcement of a constraint. Big M formulations often exhibittrickle flow, and sometimes they behave in unstable ways.<strong>ILOG</strong> <strong>CPLEX</strong> <strong>11.0</strong> — USER’ S MANUAL 355

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!