Dum loquimur, fugerit invida aetas: carpe diem, quam minimum credula postero. (Orazio, Odi, I, 11, 7-8)

oRatio is an Integrated Logic and Constraint based solver which takes inspiration from both Logic Programming (LP) and Constraint Programming (CP).

The repository structure is compatible with the NetBeans editor folder structure, therefore, the easiest way for building oRatio is to clone the repository, open it with NetBeans and build the project. Nonetheless, oRatio can be built regardless if NetBeans by using Apache Ant simply going within the project folder and starting an ant building script. Precompiled builds will be available soon.

The unique requirement for building the oRatio framework is to have the Java SE (JDK) version 8 or greater.

The oRatio environment can be used either as a command line tool or as a library.

The default usage syntax is the following:

java -jar oRatio.jar [options] <input-files>
Options:
-show-planning-graph    Shows the generated planning graph

where <input-files> is a list of input files containing RDDL code snippets.

Using oRatio as a library is pretty simple. It is enough to create a Solver instance and interact with it.

For example, the following code creates a solver instance, reads an RDDL script which requires the creation of a new real variable called a and retrieves the newly created variable through the Solver. At a later time, the solver reads the /examples/test/test_sv_0.rddl file from the file system and finds a solution.

Solver s = new Solver();

s.read("real a;");

IArithItem a = s.get("a");

s.read(new File("/examples/test/test_sv_0.rddl"));

boolean solution = s.solve();

if(solution) {
    System.out.println("We have found a solution!!");
} else {
    System.out.println("The problem is unsolvable..");
}

More information about using oRatio as a library can be found here.

The oRatio input language is called oRatio Domain Description Language (RDDL). The basic core of the oRatio architecture provides an object-oriented virtual environment for the definition of objects and constraints among them. Every object in the oRatio environment is an instance of a specific type. oRatio distinguishes among primitive types (i.e., bools, ints, reals, enums and strings) and user defined complex types (e.g., robots, trucks, locations, etc.). More information about the RDDL can be found here.

The constraint network is maintained by means of the ac-lib library which provides features for creating variables and for enforcing constraints among them.