


Overview
cpprb is a python (CPython) module providing replay buffer classes for
reinforcement learning.
Major target users are researchers and library developers.
You can build your own reinforcement learning algorithms together with
your favorite deep learning library (e.g. TensorFlow, PyTorch).
cpprb forcuses speed, flexibility, and memory efficiency.
By utilizing Cython, complicated calculations (e.g. segment tree for
prioritized experience replay) are offloaded onto C++.
(The name cpprb comes from "C++ Replay Buffer".)
In terms of API, initially cpprb referred to OpenAI Baselines'
implementation. The current version of cpprb has much more
flexibility. Any NumPy compatible types of any numbers of values can
be stored (as long as memory capacity is sufficient). For example, you
can store the next action and the next next observation, too.
Installation
cpprb requires following softwares before installation.
- C++17 compiler (for installation from source)
- Python 3
- pip
Additionally, here are user's good feedbacks for installation at Ubuntu.
(Thanks!)
Install from PyPI (Recommended)
The following command installs cpprb together with other dependencies.
pip install cpprb
Depending on your environment, you might need sudo
or --user
flag
for installation.
On supported platflorms (Linux x86-64, Windows amd64, and macOS
x8664), binary packages hosted on PyPI can be used, so that you don't
need C++ compiler. On the other platforms, such as 32bit or
arm-architectured Linux and Windows, you cannot install from binary,
and you need to compile by yourself. Please be patient, we plan to
support wider platforms in future.
If you have any troubles to install from binary, you can fall back to
source installation by passing --no-binary
option to the above pip
command. (In order to avoid NumPy source installation, it is better to
install NumPy beforehand.)
pip install numpy
pip install --no-binary cpprb
Install from source code
First, download source code manually or clone the repository;
git clone https://gitlab.com/ymd_h/cpprb.git
Then you can install in the same way;
cd cpprb
pip install .
For this installation, you need to convert extended Python (.pyx) to
C++ (.cpp) during installation, it takes longer time than installation
from PyPI.
Usage
Basic Usage
Basic usage is following step;
- Create replay buffer (
ReplayBuffer.__init__
) - Add transitions (
ReplayBuffer.add
)
- Reset at episode end (
ReplayBuffer.on_episode_end
)
- Sample transitions (
ReplayBuffer.sample
)
Example Code
Here is a simple example for storing standard environment (aka. obs
,
act
, rew
, next_obs
, and done
).
from cpprb import ReplayBuffer
buffer_size = 256
obs_shape = 3
act_dim = 1
rb = ReplayBuffer(buffer_size,
env_dict ={"obs": {"shape": obs_shape},
"act": {"shape": act_dim},
"rew": {},
"next_obs": {"shape": obs_shape},
"done": {}})
obs = np.ones(shape=(obs_shape))
act = np.ones(shape=(act_dim))
rew = 0
next_obs = np.ones(shape=(obs_shape))
done = 0
for i in range(500):
rb.add(obs=obs,act=act,rew=rew,next_obs=next_obs,done=done)
if done:
# Together with resetting environment, call ReplayBuffer.on_episode_end()
rb.on_episode_end()
batch_size = 32
sample = rb.sample(batch_size)
# sample is a dictionary whose keys are 'obs', 'act', 'rew', 'next_obs', and 'done'
Construction Parameters
(See also API reference)
Name | Type | Optional | Discription |
---|
size | int | No | Buffer size |
env_dict | dict | Yes (but unusable) | Environment definition (See here) |
next_of | str or array-like of str | Yes | Memory compression (See here) |
stack_compress | str or array-like of str | Yes | Memory compression (See here) |
default_dtype | numpy.dtype | Yes | Fall back data type |
Nstep | dict | Yes | Nstep configuration (See here) |
mmap_prefix | str | Yes | mmap file prefix (See here) |
Notes
Flexible environment values are defined by env_dict
when buffer
creation. The detail is described at document.
Since stored values have flexible name, you have to pass to
ReplayBuffer.add
member by keyword.
Features
cpprb provides buffer classes for building following algorithms.
cpprb features and its usage are described at following pages:
Design
Column-oriented and Flexible
One of the most distinctive design of cpprb is column-oriented
flexibly defined transitions. As far as we know, other replay buffer
implementations adopt row-oriented flexible transitions (aka. array of
transition class) or column-oriented non-flexible transitions.
In deep reinforcement learning, sampled batch is divided into
variables (i.e. obs
, act
, etc.). If the sampled batch is
row-oriented, users (or library) need to convert it into
column-oriented one. (See doc, too)
Batch Insertion
cpprb can accept addition of multiple transitions simultaneously. This
design is convenient when batch transitions are moved from local
buffers to a global buffer. Moreover it is more efficient because of
not only removing pure-Python for
loop but also suppressing
unnecessary priority updates for PER. (See doc, too)
Minimum Dependency
We try to minimize dependency. Only NumPy is required during its
execution. Small dependency is always preferable to avoid dependency
hell.
Contributing to cpprb
Any contribution are very welcome!
Bigger commumity makes development more active and improve cpprb.
Q & A at Forum
When you have any problems or requests, you can check Discussions on
GitHub.com. If you still cannot find any information, you can post
your own.
We keep issues on GitLab.com and users are still allowed to open
issues, however, we mainly use the place as development issue tracker.
Merge Request (Pull Request)
cpprb follows local rules:
- Branch Name
- "HotFix***" for bug fix
- "Feature***" for new feature implementation
- docstring
- Unit Test
- Put test code under "test/" directory
- Can test by
python -m unittest <Your Test Code>
command - Continuous Integration on GitLab CI configured by
.gitlab-ci.yaml
- Open an issue and associate it to Merge Request
Step by step instruction for beginners is described at here.
Links
cpprb sites
cpprb users' repositories
Example usage at Kaggle competition
Japanese Documents
License
cpprb is available under MIT license.
MIT License
Copyright (c) 2019 Yamada Hiroyuki
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
Citation
We would be very happy if you cite cpprb in your papers.
@misc{Yamada_cpprb_2019,
author = {Yamada, Hiroyuki},
month = {1},
title = {{cpprb}},
url = {https://gitlab.com/ymd_h/cpprb},
year = {2019}
}
- 3rd Party Papers citing cpprb