Optimization Software Class Libraries Optimization Software Class Libraries Distribution Cooperation and Hybridization for Combinatorial Optimization A Framework for Local Search Heuristics for Combinatorial Optimization Problems Hotframe: A Heuristic Optimization Framework Writing Local Search Algorithms Using Easylocal++ Integrating Heuristic Search and One Way Constraints in the Iopt Toolkit The OptQuest Callable Library A Constraint Programming Toolkit for Local Search The Modeling Language OPL — A Short Overview Genetic Algorithm Optimization Software Class Libraries. Optimization problems in practice are diverse and evolve over time giving rise to quirements both for ready to use optimization software packages and for optimization software libraries which provide more or less adaptable building blocks for app cation specific software systems. In order to apply optimization methods to a new type of problem corresponding models and algorithms have to be “coded” so that they are accessible to a computer. One way to achieve this step is the use of a mod ing language. Such modeling systems provide an excellent interface between models and solvers but only for a limited range of model types (in some cases for example linear) due in part to limitations imposed by the solvers. Furthermore while m eling systems especially for heuristic search are an active research topic it is still an open question as to whether such an approach may be generally successful. Modeling languages treat the solvers as a “black box” with numerous controls. Due to variations for example with respect to the pursued objective or specific problem properties dressing real world problems often requires special purpose methods. Thus we are faced with the difficulty of efficiently adapting and applying appropriate methods to these problems. Optimization software libraries are intended to make it relatively easy and cost effective to incorporate advanced planning methods in application specific software systems. A general classification provides a distinction between callable packages nume cal libraries and component libraries.