Neural Network Libraries

Neural Network Libraries is a deep learning framework that is intended to be used for research, development and production. We aim to have it running everywhere: desktop PCs, HPC clusters, embedded devices and production servers.

Neural Network Libraries - CUDA extension: An extension library of Neural Network Libraries that allows users to speed-up the computation on CUDA-capable GPUs.
Neural Network Libraries - Examples: Working examples of Neural Network Libraries from basic to state-of-the-art.
Neural Network Console: A Windows GUI app for neural network development.

Installation

Installing Neural Network Libraries is easy:

pip install nnabla

This installs the CPU version of Neural Network Libraries. GPU-acceleration can be added by installing the CUDA extension with pip install nnabla-ext-cuda.

For more details, see the installation section of the documentation.

Building from Source

See Build Manuals.

Running on Docker

For details on running on Docker, see the installation section of the documentation.

Features

Easy, flexible and expressive

The Python API built on the Neural Network Libraries C++11 core gives you flexibility and productivity. For example, a two layer neural network with classification loss can be defined in the following 5 lines of codes (hyper parameters are enclosed by <>).

import nnabla as nn
import nnabla.functions as F
import nnabla.parametric_functions as PF

x = nn.Variable(<input_shape>)
t = nn.Variable(<target_shape>)
h = F.tanh(PF.affine(x, <hidden_size>, name='affine1'))
y = PF.affine(h, <target_size>, name='affine2')
loss = F.mean(F.softmax_cross_entropy(y, t))

Training can be done by:

import nnabla.solvers as S

# Create a solver (parameter updater)
solver = S.Adam(<solver_params>)
solver.set_parameters(nn.get_parameters())

# Training iteration
for n in range(<num_training_iterations>):
    # Setting data from any data source
    x.d = <set data>
    t.d = <set label>
    # Initialize gradients
    solver.zero_grad()
    # Forward and backward execution
    loss.forward()
    loss.backward()
    # Update parameters by computed gradients
    solver.update()

The dynamic computation graph enables flexible runtime network construction. Neural Network Libraries can use both paradigms of static and dynamic graphs, both using the same API.

x.d = <set data>
t.d = <set label>
drop_depth = np.random.rand(<num_stochastic_layers>) < <layer_drop_ratio>
with nn.auto_forward():
    h = F.relu(PF.convolution(x, <hidden_size>, (3, 3), pad=(1, 1), name='conv0'))
    for i in range(<num_stochastic_layers>):
        if drop_depth[i]:
            continue  # Stochastically drop a layer
        h2 = F.relu(PF.convolution(x, <hidden_size>, (3, 3), pad=(1, 1), 
                                   name='conv%d' % (i + 1)))
        h = F.add2(h, h2)
    y = PF.affine(h, <target_size>, name='classification')
    loss = F.mean(F.softmax_cross_entropy(y, t))
# Backward computation (can also be done in dynamically executed graph)
loss.backward()

Portable and multi-platform

Python API can be used on Linux and Windows
Most of the library code is written in C++11, deployable to embedded devices

Extensible

Easy to add new modules like neural network operators and optimizers
The library allows developers to add specialized implementations (e.g., for FPGA, ...). For example, we provide CUDA backend as an extension, which gives speed-up by GPU accelerated computation.

Efficient

High speed on a single CUDA GPU
Memory optimization engine
Multiple GPU support

Documentation

https://nnabla.readthedocs.org

Getting started

A number of Jupyter notebook tutorials can be found in the tutorial folder. We recommend starting from by_examples.ipynb for a first working example in Neural Network Libraries and python_api.ipynb for an introduction into the Neural Network Libraries API.
We also provide some more sophisticated examples at nnabla-examples repository.
C++ API examples are avaiailable in examples/cpp.

Contribution guide

The technology is rapidly progressing, and researchers and developers often want to add their custom features to a deep learning framework. NNabla is really nice in this point. The architecture of Neural Network Libraries is clean and quite simple. Also, you can add new features very easy by the help of our code template generating system. See the following link for details.

Contribution guide

PeterTeng/nnabla