A coder’s guide to answer set programming

What is Answer Set Programming?

Answer Set Programming (ASP) is a programming language mainly used for modelling in artificial intelligence applications. It lends itself to complex search and optimization problems from domains such as planning, scheduling, etc. ASP is a declarative language, meaning instead of writing a “step by step” list (i.e. an algorithm) for the computer on how to calculate something, we specify just how a valid solution looks by means of logic-based rules. The software needed to run ASP code (i.e. the interpreter) is called an ASP Solver.

Getting Started

This section will walk you through the steps to install an ASP solver on your computer and solve your first program.

Installing the Alpha ASP solver

Alpha is an actively developed ASP solver written in Java. In order to run it, you need a Java Runtime Environment (JRE) compatible with Java 8. Start by downloading the latest release of Alpha. Place the Alpha distribution jar in a folder of your choosing and place the following script in a location included in your PATH variable in order to have Alpha available from every directory:

#!/bin/bash

java -jar /path/to/alpha-jar/alpha-cli-app-x.y.z-bundled.jar $@

Running a hello world program with Alpha

Once you’ve downloaded and installed Alpha, try the following call:

$ alpha-solver -str "helloWorld."

The output should look something like

Answer set 1:
{ helloWorld }
SATISFIABLE

Congratulations! Now that you’ve installed Alpha and verified it works, you can start coding along with the ASP tutorial