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Getting Started

Getting a problem

The idea behind the Algobattle framework is that course instructors will come up with some problem (in the theoretical computer science meaning) that students will then write code to solve. The Algobattle program can then take the problem definition and the code from all the student teams and score how good each team is at solving the problem.

Tip

Now's a great time to remember to activate the Python environment you installed Algobattle into (conda activate algobattle).

Problem spec files

The most common way your instructors will give you problem definitions is by uploading them to your Algobattle website. On the specific problem's page you can then download an Algobattle problem spec file with the .algo extension. This file contains all the information we need.

A peek behind the curtain

Despite their very fancy looking extension, .algo files really just zip files with a few files inside. Algobattle uses these to set up your project folders for you, but it doesn't handle things very well if you feed it data that doesn't have that structure, so the file extension is there to remind you that you're not meant to process these files manually. If you're curious you can unzip them and take a look inside yourself.

Installed problems

Another way is to install a Python package that provides one or more problems. For example, our Algobattle Problem package which contains a selection of basic problems. We can install it with pip just like the Algobattle base package:

pip install algobattle-problems

Setting up the workspace

Now we can set up our dev environment where we write the code to solve the problem. I'll be showing you some folder structures throughout but obviously the exact structure and names aren't mandatory. Let's start with a base folder which should probably contain a .git folder and not much else.

With the console in our base folder we can use Algobattle to initialize our project for us, you can use either a problem spec or an installed problem for this.

algobattle init -p path/to/spec/file.algo

algobattle init -p "Problem Name"

Note

This tutorial will use the Pairsum problem as an example, if you're following along your project folder will look slightly different depending on which problem you chose and what your course instructors decided to include with it.

Once this has run the folder should look something like this

.
└─ Pairsum
   ├─ generator/
   │  └─ Dockerfile
   ├─ results/
   ├─ solver/
   │  └─ Dockerfile
   ├─ .gitignore
   ├─ algobattle.toml
   ├─ description.md    # this file may be missing, don't worry if it is!
   └─ problem.py

.
└─ Pairsum
   ├─ generator/
   │  └─ Dockerfile
   ├─ results/
   ├─ solver/
   │  └─ Dockerfile
   ├─ .gitignore
   └─ algobattle.toml

What Algobattle has done is make a new project directory specific to this problem we're working with, and then initialized all the required files and folders in it. Let's navigate into it for the rest of the tutorial.

cd Pairsum

The algobattle.toml config file

Project level configuration is done inside the algobattle.toml file so let's take a look at what's in there already.

[match]
problem = "Pairsum"
# there might be more settings here

[teams."Red Pandas"]
generator = "generator"
solver = "solver"

[match]
problem = "Pairsum"

[teams."Red Pandas"]
generator = "generator"
solver = "solver"

The config file is split into a few tables, match specifies exactly what each Algobattle match is going to look like. This means that you will probably never want to change things in there since you want to develop your programs for the same conditions they're going to see during the scored matches run on the server. Feel free to play with the teams, problem, and project tables as much as you want, nothing in them affects the structure of the match or anything on the server. In particular, the team name used here doesn't need to match the one used on your Algobattle website. The filled in settings so far all just are paths to where Algobattle can find certain files or folders. There's a lot more things you can configure, but we're happy with the default values for now.

Tip

If you're curious what exactly everything in here means you can read the config docs. But for now we recommend staying here since things will be much clearer after you're familiar with things here.

The problem.py file

Note

This will only exist if you used a problem spec file.

This is what Algobattle uses as the problem definition. Once you're familiar with the way Algobattle does things you can cross-reference this to see what exactly your code needs to do. But it's also not directly meant to be human-readable and easily understandable, in particular if you're not familiar with Python and Pydantic.

The description.* file

Note

This will only exist if you used a problem spec file and your course instructors included it.

This is the version of the problem definition that's more fun to read. It can be whatever your course instructors wanted to include, but most commonly is a Markdown or Pdf file.