Copter is a tool for optimizing composable systems. A composable system is a collection of modules that can be assembled or decomposed according to certain rules. For example, a bicycle is a composable system that can be specified as:

bicycle = wheels . frame . seat

where . is a composition operator. Each module may itself be a composable system. For example:

• wheels = front_wheel . rear_wheel
• frame = hub . spokes . rim . tire . tube
• seat = saddle . post

making the following an alternative valid specification for bicycle:

bicycle = front_wheel . rear_wheel . frame . saddle . post

Modules that cannot be decomposed into other modules are atoms. All composable systems can be reduced to collections of atoms.

Given a specification of a composable system with large numbers of atoms and rules, it is sometimes useful to find alternative specifications that are shorter, less/more verbose or free from (or inclusive of) certain modules. For example, one may be interested in finding a simpler specification equivalent to:

something = front_wheel . rear_wheel . saddle . post

which would be something = wheels . seat, or another specification which is less verbose but still contains the module saddle such as something = wheels . saddle . post.

Alternative specifications such as these can be found by Copter. Copter is an optimization tool for composable system specifications based on Z3. The tool is developed primarily to optimize Concepts (a DSL for expressing asynchronous circuits using behavioral compositions) but can be used with arbitrary composable systems.

For installation and usage instructions, see the manual.