Official Implementation of Principled Fast and Meta Knowledge Learners for Continual Reinforcement Learning (ICLR 2026)

This repository contains the Pytorch implementation of our FAME continual RL algorithm "Principled Fast and Meta Knowledge Learners for Continual Reinforcement Learning". We employ our FAME algorithm in the environments of MinAtar, Atari, and MetaWorld, respectively.

Environment 1: MinAar

Environmental Setup

pip install -r MinAtar/requirements.txt # python=3.10

baseline methods:

For example, we can run the baseline algorithms on the sequence 3 of tasks.

# Reset
python DQN.py --lr1=1e-5 --seed=0 --save --save-model --seq 3 --reset 1 --gpu 0 
# Finetune
python DQN.py --lr1=1e-5 --seed=0 --save --save-model --seq 3 --reset 0 --gpu 0 
# Multi-head
python DQN_multi_task.py --lr1=1e-5 --seed=0 --save --save-model --seq 3 --gpu 0
# LargeBuffer
python DQN_large_buffer.py --lr1=1e-4 --seed=0 --save --save-model --seq 3 --gpu 0 
# PT-DQN
python PT_DQN_half.py --lr1=1e-8 --lr2=1e-4 --decay=0.75 --seed=0 --save --save-model --seq 3 --gpu 0 

Our FAME approach

Argument	Value	Description
lr1	1e-3	Learning rate for Fast Learner
lr2	1e-5	Learning rate for Meta Learner
size_fast2meta	12000	N： Number of samples collected in each fast learning to replay buffer (12000 × 7 = 84000 < 100000)
size_meta	100000	Size of meta replay buffer (same as original simple DQN setting)
warmstep	50000	L: Warm-up step with behevior cloning
detection_step	1200	n: number of steps for policy evaluation
lambda_reg	1.0	Regularization hyperparameter in behavior cloning
use_ttest	0	0: empirical ranking, 1: t-test for one-vs-all hypothesis test

---

python FAME.py --lr1=1e-3 --lr2=1e-5 --size_fast2meta 12000 --detection_step 600 --seed=1 --save --save-model --seq 1 --gpu 0 --warmstep 50000  --lambda_reg 1.0 

bash

We can run the bash file, but we suggest to tailor the bash code with your compute resources.

bash run.sh

Acknowledgement

This implementation in MinAtar is adapted from the released code of the paper Prediction and Control in Continual Reinforcement Learning (NeurIPS 2023).

Environment 2: Atari Games

Environmental Setup

pip install -r Atari/requirements.txt

Baselines:

Argument	Value	Description
--algorithm	from-scratch	Reset
	finetune	Finetune
	packnet	Packnet
	prog-net	ProgressiveNet
--env	ALE/SpaceInvaders-v5	Sequence in Spaceinvader
	ALE/Freeway-v5	Sequence in Freeway

---

# example: packnet
python run_experiments.py --algorithm packnet --env ALE/SpaceInvaders-v5 --seed 1 --start-mode 0

Our FAME Approach

We use a set of default hyper-parameters without sweeping them, but it already suggests the superiority in the performance.

In the original code, we run run_experiments.py to conduct all baselines algorithms. A straightforward application of this implementation logic to FAME is not applicable as the meta buffer will require the huge memory resources. Therefore, we modify the implementation log and run the FAME algorithm via run_ppo_FAME.py.

python run_ppo_FAME.py --model-type=FAME --env-id=ALE/Freeway-v5 --seed=0 --save-dir=agents --total-timesteps=1000000 --epoch_meta 200
python run_ppo_FAME.py --model-type=FAME --env-id=ALE/SpaceInvaders-v5 --seed=0 --save-dir=agents --total-timesteps=1000000 --epoch_meta 200

Evaluation

python process_results_pre.py # from event data to csv
python process_results.py # from csv to CRL-relavant metrics

Acknowledgement

This implementation in Atari is adapted from the released code of the paper Self-composing policies for scalable continual reinforcement learning (ICML 2024).

Environment 3: MetaWorld

Environmental Setup

pip install -r Metaworld/requirements.txt

Note: The requirements file includes mujoco and metaworld. Please ensure you have the necessary system dependencies for MuJoCo installed.

1. Running FAME & Standard Baselines

To run the main experiments using FAME and standard baselines (Reset, Average, Finetune), use the following command:

python test_main.py --seed 0 --method buffer --gpu 0 --store_traj_num 10 --use_ttest 1 --env metaworld_sequence_set18

Arguments Reference

Argument	Value	Description
--method	buffer	FAME-KL (Our method)
	buffer_wd	FAME-MD (Our method variant)
	independent	Reset (Baseline: Train from scratch)
	average	Average (Baseline: Parameter averaging)
	continue	Finetune (Baseline: Continual learning without regularization)
--env	metaworld_sequence_set6	Sequence of 6 tasks
	metaworld_sequence_set12	Sequence of 12 tasks
	metaworld_sequence_set18	Sequence of 18 tasks
	metaworld_sequence_set22	Sequence of CW10

---

2. Running Advanced Baselines (PackNet, ProgressiveNet, CompoNet)

These baselines are located in a separate directory.

Prerequisites

Important: You must first run the simple algorithm (SAC) to generate the initial model for the first task, which is required by other baselines.

Execution Steps

1. Navigate to the experiment directory:

   cd Metaworld/baselines_packnet_progressivenet_componet/experiments/meta-world

2. Run the experiment:

   python run_experiments.py --algorithm simple --seed 0 --start-mode 0 --task-sequence 6

Arguments Reference

Argument	Value	Description
--algorithm	simple	SAC (Standard Soft Actor-Critic)
	packnet	PackNet
	prognet	ProgressiveNet
	componet	CompoNet

Reference

Please cite our paper if you use our implementation in your research:

@inproceedings{
sun2026principled,
title={Principled Fast and Meta Knowledge Learners for Continual Reinforcement Learning},
author={Ke Sun and Hongming Zhang and Jun Jin and Chao Gao and Xi Chen and Wulong Liu and Linglong Kong},
booktitle={The Fourteenth International Conference on Learning Representations},
year={2026},
url={https://openreview.net/forum?id=loNTDX3wTn}
}