A micro-credential (aka micro-certificate) is a digital certificate attesting that you have gained knowledge and skills in a specific area. It should be internationally recognized and verifiable using an online EU-wide verification system.

A micro-credential can be obtained both by the university students and external participants.

External Participants

If you are not a university student, you can apply to the Reinforcement Learning micro-credential course here and then attend the course along the university students. Upon successfully passing the course, a micro-credential is issued.

The price of the course is 5 000 Kč. If you require a tax receipt, please inform Magdaléna Kokešová within three business days after the payment.

The lectures run for 14 weeks from Feb 17 to May 22, with the examination period continuing until the end of September. Please note that the organization of the course and the setup instructions will be described at the first lecture; if you have already applied, you do not need to do anything else until that time.

University Students

If you have passed the course (in academic year 2025/26 or later) as a part of your study plan, you can obtain a micro-credential by paying only an administrative fee of 300 Kč; if you passed the course but it is not in your study plan, the administrative fee is 500 Kč. Detailed instructions how to get the micro-credential will be sent to the course participants during the examination period.

The lecture content, including references to study materials.

The main study material is the Reinforcement Learning: An Introduction; second edition by Richard S. Sutton and Andrew G. Barto (referred to as RLB). It is available online and also as a hardcopy.

References to study materials cover all theory required at the exam, and sometimes even more – the references in italics cover topics not required for the exam.

1. Introduction to Reinforcement Learning

 Feb 17 Slides PDF Slides Lecture MonteCarlo Practicals Questions bandits monte_carlo

• History of RL [Chapter 1 of RLB]
• Multi-armed bandits [Sections 2-2.6 of RLB]
• Markov Decision Process [Sections 3-3.3 of RLB]
• Policies and Value Functions [Sections 3.5-3.6 of RLB]

Requirements

To pass the practicals, you need to obtain at least 80 points, excluding the bonus points. Note that all surplus points (both bonus and non-bonus) will be transfered to the exam. In total, assignments for at least 120 points (not including the bonus points) will be available, and if you solve all the assignments (any non-zero amount of points counts as solved), you automatically pass the exam with grade 1.

Environment

The tasks are evaluated automatically using the ReCodEx Code Examiner.

The evaluation is performed using Python 3.11, Gymnasium, and PyTorch. You should install the exact version of these packages yourselves.

Teamwork

Solving assignments in teams (of size at most 3) is encouraged, but everyone has to participate (it is forbidden not to work on an assignment and then submit a solution created by other team members). All members of the team must submit in ReCodEx individually, but can have exactly the same sources/models/results. Each such solution must explicitly list all members of the team to allow plagiarism detection using this template.

No Cheating

Cheating is strictly prohibited and any student found cheating will be punished. The punishment can involve failing the whole course, or, in grave cases, being expelled from the faculty. While discussing assignments with any classmate is fine, each team must complete the assignments themselves, without using code they did not write (unless explicitly allowed). Of course, inside a team you are allowed to share code and submit identical solutions. Note that all students involved in cheating will be punished, so if you share your source code with a friend, both you and your friend will be punished. That also means that you should never publish your solutions.

AI Assistance when Solving Assignments

Relying blindly on AI during learning seems to have negative¹ effect² on skill acquisition. Therefore, you are not allowed to directly copy the assignment descriptions to GenAI and you are not allowed to directly use or copy-paste source code generated by GenAI. However, discussing your manually written code with GenAI is fine.

bandits

 Deadline: Mar 04, 22:00  3 points  Tests

Implement the $ε$-greedy strategy for solving multi-armed bandits.

Start with the bandits.py template, which defines MultiArmedBandits environment, which has the following three methods:

• reset(): reset the environment
• step(action) → reward: perform the chosen action in the environment, obtaining a reward
• greedy(epsilon): return True with probability 1-epsilon

Your goal is to implement the following solution variants:

• alpha$=0$: perform $ε$-greedy search, updating the estimates using averaging.
• alpha$≠0$: perform $ε$-greedy search, updating the estimates using a fixed learning rate alpha.

Note that the initial estimates should be set to a given value, and epsilon can be zero, in which case purely greedy actions are used.

1.39 0.08

1.48 0.22

1.37 0.09

1.52 0.04

monte_carlo

 Deadline: Mar 04, 22:00  4 points

Solve the discretized CartPole-v1 environment from the Gymnasium library using the Monte Carlo reinforcement learning algorithm. The gymnasium environments have the following methods and properties:

• observation_space: the description of environment observations
• action_space: the description of environment actions
• reset() → new_state, info: starts a new episode, returning the new state and additional environment-specific information
• step(action) → new_state, reward, terminated, truncated, info: perform the chosen action in the environment, returning the new state, obtained reward, boolean flags indicating a terminal state and episode truncation, and additional environment-specific information

We additionally extend the gymnasium environment by:

• episode: number of the current episode (zero-based)
• reset(start_evaluation=False) → new_state, info: if start_evaluation is True, an evaluation is started

Once you finish training (which you indicate by passing start_evaluation=True to reset), your goal is to reach an average return of 490 during 100 evaluation episodes. Note that the environment prints your 100-episode average return each 10 episodes even during training.

Start with the monte_carlo.py template, which parses several useful parameters, creates the environment and illustrates the overall usage.

During evaluation in ReCodEx, three different random seeds will be employed, and you need to reach the required return on all of them. Time limit for each test is 5 minutes.

Submitting to ReCodEx

When submitting a competition solution to ReCodEx, you should submit a trained agent and a Python source capable of running it.

Furthermore, please also include the Python source and hyperparameters you used to train the submitted model. But be careful that there still must be exactly one Python source with a line starting with def main(.

Do not forget about the maximum allowed model size and time and memory limits.

Competition Evaluation

• Before the deadline, ReCodEx prints the exact performance of your agent, but only if it is worse than the baseline.

  If you surpass the baseline, the assignment is marked as solved in ReCodEx and you immediately get regular points for the assignment. However, ReCodEx does not print the reached performance.

• After the first deadline, the latest submission of every user surpassing the required baseline participates in a competition. Additional bonus points are then awarded according to the ordering of the performance of the participating submissions.

• After the competition results announcement, ReCodEx starts to show the exact performance for all the already submitted solutions and also for the solutions submitted later.

Repeated Participation in Competitions

• If a participant got non-zero points for a competition task already in previous years, they are treated slightly differently. Namely, every team with one or more returning participants still get competition points, but
  • the returning team results are not shown on the slides on the practicals;
  • the returning team results are shown in italics in ReCodEx;
  • the returning team results are not used to compute the thresholds for competition points.

What Is Allowed

• Unless stated otherwise, you can use any algorithm to solve the competition task at hand, but the implementation must be created by you and you must understand it fully. You can of course take inspiration from any paper or existing implementation, but please reference it in that case.
• PyTorch and JAX are available in ReCodEx (but there are no GPUs).

Install

• What Python version to use

  The recommended Python version is 3.11. This version is used by ReCodEx to evaluate your solutions. Supported Python versions are 3.11–3.13 (some dependencies do not yet provide wheels for Python 3.14).

  You can find out the version of your Python installation using python3 --version.

• Installing to central user packages repository

  You can install all required packages to central user packages repository using python3 -m pip install --user --no-cache-dir --extra-index-url=https://download.pytorch.org/whl/cu128 npfl139.

  On Linux and Windows, the above command installs CUDA 12.8 PyTorch build, but you can change cu128 to:

  • cpu to get CPU-only (smaller) version,
  • cu124 to get CUDA 12.4 build,
  • rocm7.1 to get AMD ROCm 7.1 build (Linux only).

  On macOS, the --extra-index-url has no effect and the Metal support is installed in any case.

  To update the npfl139 package later, use python3 -m pip install --user --upgrade npfl139.

• Installing to a virtual environment

  Python supports virtual environments, which are directories containing independent sets of installed packages. You can create a virtual environment by running python3 -m venv VENV_DIR followed by VENV_DIR/bin/pip install --no-cache-dir --extra-index-url=https://download.pytorch.org/whl/cu128 npfl139. (or VENV_DIR/Scripts/pip on Windows).

  Again, apart from the CUDA 12.8 build, you can change cu128 on Linux and Windows to:

  • cpu to get CPU-only (smaller) version,
  • cu124 to get CUDA 12.4 build,
  • rocm7.1 to get AMD ROCm 7.1 build (Linux only).

  To update the npfl139 package later, use VENV_DIR/bin/pip install --upgrade npfl139.

• Windows installation

  • On Windows, it can happen that python3 is not in PATH, while py command is – in that case you can use py -m venv VENV_DIR, which uses the newest Python available, or for example py -3.11 -m venv VENV_DIR, which uses Python version 3.11.

  • If MuJoCo environments fail during construction, make sure the path of the Python site packages contains no non-ASCII characters. If it does, you can create a new virtual environment in a suitable directory to circumvent the problem.

  • If you encounter a problem creating the logs in the args.logdir directory, a possible cause is that the path is longer than 260 characters, which is the default maximum length of a complete path on Windows. However, you can increase this limit on Windows 10, version 1607 or later, by following the instructions.

• MacOS installation

  • If you encounter issues with SSL certificates (certificate verify failed: self-signed certificate in certificate chain), you probably need to run the Install Certificates.command, which should be executed after installation; see https://docs.python.org/3/using/mac.html#installation-steps.

• GPU support on Linux and Windows

  PyTorch supports NVIDIA GPU or AMD GPU out of the box, you just need to select appropriate --extra-index-url when installing the packages.

  If you encounter problems loading CUDA or cuDNN libraries, make sure your LD_LIBRARY_PATH does not contain paths to older CUDA/cuDNN libraries.

Git

• Is it possible to keep the solutions in a Git repository?

  Definitely. Keeping the solutions in a branch of your repository, where you merge them with the course repository, is probably a good idea. However, please keep the cloned repository with your solutions private.

• On GitHub, do not create a public fork containing your solutions.

  If you keep your solutions in a GitHub repository, please do not create a clone of the repository by using the Fork button; this way, the cloned repository would be public.

  • If you created a public fork and want to make it private, you need to start by pressing Leave fork network in the repository settings; only then you can change the visibility to private.

  Of course, if you want to create a pull request, GitHub requires a public fork and you need to create it, just do not store your solutions in it (so you might end up with two repositories, a public fork for pull requests and a private repo for your own solutions).

• How to clone the course repository?

  To clone the course repository, run

  git clone https://github.com/ufal/npfl139
  

  This creates the repository in the npfl139 subdirectory; if you want a different name, add it as an additional parameter.

  To update the repository, run git pull inside the repository directory.

• How to merge the course repository updates into a private repository with additional changes?

  It is possible to have a private repository that combines your solutions and the updates from the course repository. To do that, start by cloning your empty private repository, and then run the following commands in it:

  git remote add course_repo https://github.com/ufal/npfl139
  git fetch course_repo
  git checkout --no-track course_repo/master
  

  This creates a new remote course_repo and a clone of the master branch from it; however, git pull and git push in this branch will operate on the repository your cloned originally.

  To update your branch with the changes from the course repository, run

  git fetch course_repo
  git merge course_repo/master
  

  while in your branch (the command git pull --no-rebase course_repo master has the same effect). Of course, it might be necessary to resolve conflicts if both you and the course repository modified the same lines in the same files.

ReCodEx

• What files can be submitted to ReCodEx?

  You can submit multiple files of any type to ReCodEx. There is a limit of 20 files per submission, with a total size of 20MB.

• What file does ReCodEx execute and what arguments does it use?

  Exactly one file with py suffix must contain a line starting with def main(. Such a file is imported by ReCodEx and the main method is executed (during the import, __name__ == "__recodex__").

  The file must also export an argument parser called parser. ReCodEx uses its arguments and default values, but it overwrites some of the arguments depending on the test being executed; the template always indicates which arguments are set by ReCodEx and which are left intact.

• What are the time and memory limits?

  The memory limit during evaluation is 1.5GB. The time limit varies, but it should be at least 10 seconds and at least twice the running time of my solution.

• Do agents need to be trained directly in ReCodEx?

  No, you can pre-train your agent locally (unless specified otherwise in the task description).

Requirements

To pass the practicals, you need to obtain at least 80 points, excluding the bonus points. Note that all surplus points (both bonus and non-bonus) will be transfered to the exam. In total, assignments for at least 120 points (not including the bonus points) will be available, and if you solve all the assignments (any non-zero amount of points counts as solved), you automatically pass the exam with grade 1.

To pass the exam, you need to obtain at least 60, 75, or 90 points out of 100-point exam to receive a grade 3, 2, or 1, respectively. The exam consists of 100-point-worth questions from the list below (the questions are randomly generated, but in such a way that there is at least one question from every but the last lecture). In addition, you can get surplus points from the practicals and at most 10 points for community work (i.e., fixing slides or reporting issues) – but only the points you already have at the time of the exam count. You can take the exam without passing the practicals first.

Exam Questions

Lecture 1 Questions

• Derive how to incrementally update a running average (how to compute an average of $N$ numbers using the average of the first $N-1$ numbers). [5]

• Describe multi-arm bandits and write down the $\epsilon$-greedy algorithm for solving it. [5]

• Define a Markov Decision Process, including the definition of a return. [5]

• Describe how a partially observable Markov decision process extends a Markov decision process and how the agent is altered. [5]

• Define a value function, such that all expectations are over simple random variables (actions, states, rewards), not trajectories. [5]

• Define an action-value function, such that all expectations are over simple random variables (actions, states, rewards), not trajectories. [5]

• Express a value function using an action-value function, and express an action-value function using a value function. [5]

• Define optimal value function, optimal action-value function, and the optimal policy. [5]

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