BreakRL#

Learn reinforcement learning through failure.

BreakRL is a bilingual, failure-first set of RL lecture notes. Each chapter explains a mechanism, then removes it so you can see the failure.

Start in three minutes#

  1. Open the minimum demo and drag the coverage slider (a teaching plot; it does not train a model);

  2. Open Failure Atlas #8 (healthy offline loss, collapsing returns);

  3. Read the Offline RL chapter: text PDF and the saved experiment.

Reading the site needs no install. Pages render saved outputs and do not train. The catalog below is the rest of the book; start with the loop above, not Chapter 1.

How to read#

  1. Read the chapter text for the problem, formulas, and mechanism;

  2. Open the experiment notebook and watch the algorithm on a small task;

  3. Compare the ablations: a finished run is not the same as a method that works.

When training does not converge, look up the symptom in the RL Failure Atlas (“symptom → mechanism → reproduction → fix”).

All chapters#

#

Chapter

Text

Experiments

Run

1

Multi-Armed Bandits: Exploration vs Exploitation

PDF

Notebook

Colab

2

Markov Decision Processes

PDF

Notebook

Colab

3

Temporal-Difference Learning

PDF

Notebook

Colab

4

DQN: Neural Value Learning

PDF

Notebook

Colab

5

Policy Gradient / REINFORCE

PDF

Notebook

Colab

6

Actor-Critic / A2C

PDF

Notebook

Colab

7

PPO: Constrained Policy Updates

PDF

Notebook

Colab

8

SAC: Maximum-Entropy Continuous Control

PDF

Notebook

Colab

9

Offline RL: CQL and IQL

PDF

Notebook

Colab

10

Model-Based RL: Dyna-Q

PDF

Notebook

Colab

11

Decision Transformer: RL as Sequence Modeling

PDF

Notebook

Colab

12

RLHF: From Preferences to Rewards

PDF

Notebook

Colab

13

DPO: Preference Optimization without a Reward Model

PDF

Notebook

Colab

14

GRPO and RLVR: Verifiable Rewards

PDF

Notebook

Colab

Chapters 12–14 use toy sequence tasks and two-digit addition. They show the mechanisms; they are not a substitute for production RLHF, DPO, or GRPO training.

The site displays saved notebook outputs and does not train models while you read. To run the experiments, use Colab in the table above or the local install in the README.