Introducing Keras 3 for R

We’re thrilled to introduce keras3, the following model of the Keras R
package deal. keras3 is a ground-up rebuild of {keras}, sustaining the
beloved options of the unique whereas refining and simplifying the API
primarily based on precious insights gathered over the previous few years.

Keras supplies a whole toolkit for constructing deep studying fashions in
R—it’s by no means been simpler to construct, practice, consider, and deploy deep
studying fashions.

Set up

To put in Keras 3:

set up.packages("keras3")
library(keras3)
install_keras()

What’s new:

Documentation

Nice documentation is crucial, and we’ve labored laborious to ensure
that keras3 has wonderful documentation, each now, and sooner or later.

Keras 3 comes with a full refresh of the web site:
https://keras.posit.co. There, one can find guides, tutorials,
reference pages with rendered examples, and a brand new examples gallery. All
the reference pages and guides are additionally out there through R’s built-in assist
system.

In a fast-paced ecosystem like deep studying, creating nice
documentation and wrappers as soon as is just not sufficient. There additionally should be
workflows that make sure the documentation is up-to-date with upstream
dependencies. To perform this, {keras3} contains two new maintainer
options that make sure the R documentation and performance wrappers will keep
up-to-date:

• We now take snapshots of the upstream documentation and API floor.
  With every launch, all R documentation is rebased on upstream
  updates. This workflow ensures that each one R documentation (guides,
  examples, vignettes, and reference pages) and R operate signatures
  keep up-to-date with upstream. This snapshot-and-rebase
  performance is applied in a brand new standalone R package deal,
  {doctether}, which can
  be helpful for R package deal maintainers needing to maintain documentation in
  parity with dependencies.

• All examples and vignettes can now be evaluated and rendered throughout
  a package deal construct. This ensures that no stale or damaged instance code
  makes it right into a launch. It additionally means all consumer going through instance code
  now moreover serves as an prolonged suite of snapshot unit and
  integration checks.

  Evaluating code in vignettes and examples continues to be not permitted
  in keeping with CRAN restrictions. We work across the CRAN restriction
  by including extra package deal construct steps that pre-render
  examples
  and
  vignettes.

Mixed, these two options will make it considerably simpler for Keras
in R to keep up characteristic parity and up-to-date documentation with the
Python API to Keras.

Multi-backend assist

Quickly after its launch in 2015, Keras featured assist for hottest
deep studying frameworks: TensorFlow, Theano, MXNet, and CNTK. Over
time, the panorama shifted; Theano, MXNet, and CNTK have been retired, and
TensorFlow surged in reputation. In 2021, three years in the past, TensorFlow
turned the premier and solely supported Keras backend. Now, the panorama
has shifted once more.

Keras 3 brings the return of multi-backend assist. Select a backend by
calling:

use_backend("jax") # or "tensorflow", "torch", "numpy"

The default backend continues to be TensorFlow, which is the only option
for many customers in the present day; for small-to-medium sized fashions that is nonetheless the
quickest backend. Nevertheless, every backend has completely different strengths, and
having the ability to change simply will allow you to adapt to modifications as your
venture, or the frameworks themselves, evolve.

In the present day, switching to the Jax backend can, for some mannequin sorts, deliver
substantial velocity enhancements. Jax can be the one backend that has
assist for a brand new mannequin parallelism distributed coaching API. Switching
to Torch might be useful throughout improvement, usually producing easier
trackbacks whereas debugging.

Keras 3 additionally helps you to incorporate any pre-existing Torch, Jax, or Flax
module as a typical Keras layer through the use of the suitable wrapper,
letting you construct atop present initiatives with Keras. For instance, practice
a Torch mannequin utilizing the Keras high-level coaching API (compile() +
match()), or embody a Flax module as a part of a bigger Keras
mannequin. The brand new multi-backend assist helps you to use Keras à la carte.

The ‘Ops’ household

{keras3} introduces a brand new “Operations” household of operate. The Ops
household, at the moment with over 200
capabilities,
supplies a complete suite of operations sometimes wanted when
working on nd-arrays for deep studying. The Operation household
supersedes and enormously expands on the previous household of backend capabilities
prefixed with k_ within the {keras} package deal.

The Ops capabilities allow you to write backend-agnostic code. They supply a
uniform API, no matter for those who’re working with TensorFlow Tensors,
Jax Arrays, Torch Tensors, Keras Symbolic Tensors, NumPy arrays, or R
arrays.

The Ops capabilities:

• all begin with prefix op_ (e.g., op_stack())
• all are pure capabilities (they produce no side-effects)
• all use constant 1-based indexing, and coerce doubles to integers
  as wanted
• all are protected to make use of with any backend (tensorflow, jax, torch, numpy)
• all are protected to make use of in each keen and graph/jit/tracing modes

The Ops API contains:

• The whole thing of the NumPy API (numpy.*)
• The TensorFlow NN API (tf.nn.*)
• Widespread linear algebra capabilities (A subset of scipy.linalg.*)
• A subfamily of picture transformers
• A complete set of loss capabilities
• And extra!

Ingest tabular knowledge with layer_feature_space()

keras3 supplies a brand new set of capabilities for constructing fashions that ingest
tabular knowledge: layer_feature_space() and a household of characteristic
transformer capabilities (prefix, feature_) for constructing keras fashions
that may work with tabular knowledge, both as inputs to a keras mannequin, or
as preprocessing steps in a knowledge loading pipeline (e.g., a
tfdatasets::dataset_map()).

See the reference
web page and an
instance utilization in a full end-to-end
instance
to be taught extra.

New Subclassing API

The subclassing API has been refined and prolonged to extra Keras
sorts.
Outline subclasses just by calling: Layer(), Loss(), Metric(),
Callback(), Constraint(), Mannequin(), and LearningRateSchedule().
Defining {R6} proxy lessons is now not vital.

Moreover the documentation web page for every of the subclassing
capabilities now accommodates a complete itemizing of all of the out there
attributes and strategies for that kind. Take a look at
?Layer to see what’s
attainable.

Saving and Export

Keras 3 brings a brand new mannequin serialization and export API. It’s now a lot
easier to save lots of and restore fashions, and likewise, to export them for
serving.

• save_model()/load_model():
  A brand new high-level file format (extension: .keras) for saving and
  restoring a full mannequin.

  The file format is backend-agnostic. This implies that you may convert
  skilled fashions between backends, just by saving with one backend,
  after which loading with one other. For instance, practice a mannequin utilizing Jax,
  after which convert to Tensorflow for export.

• export_savedmodel():
  Export simply the ahead move of a mannequin as a compiled artifact for
  inference with TF
  Serving or (quickly)
  Posit Join. This
  is the best option to deploy a Keras mannequin for environment friendly and
  concurrent inference serving, all with none R or Python runtime
  dependency.

• Decrease degree entry factors:

  • save_model_weights() / load_model_weights():
    save simply the weights as .h5 information.
  • save_model_config() / load_model_config():
    save simply the mannequin structure as a json file.

• register_keras_serializable():
  Register customized objects to allow them to be serialized and
  deserialized.

• serialize_keras_object() / deserialize_keras_object():
  Convert any Keras object to an R listing of easy sorts that’s protected
  to transform to JSON or rds.

• See the brand new Serialization and Saving
  vignette
  for extra particulars and examples.

New random household

A brand new household of random tensor
mills.
Just like the Ops household, these work with all backends. Moreover, all of the
RNG-using strategies have assist for stateless utilization once you move in a
seed generator. This permits tracing and compilation by frameworks that
have particular assist for stateless, pure, capabilities, like Jax. See
?random_seed_generator()
for instance utilization.

Different additions:

• New form()
  operate, one-stop utility for working with tensor shapes in all
  contexts.

• New and improved print(mannequin) and plot(mannequin) methodology. See some
  examples of output within the Practical API
  information

• All new match() progress bar and stay metrics viewer output,
  together with new dark-mode assist within the RStudio IDE.

• New config
  household,
  a curated set of capabilities for getting and setting Keras international
  configurations.

• All the different operate households have expanded with new members:

Migrating from {keras} to {keras3}

{keras3} supersedes the {keras} package deal.

For those who’re writing new code in the present day, you can begin utilizing {keras3} proper
away.

If in case you have legacy code that makes use of {keras}, you might be inspired to
replace the code for {keras3}. For a lot of high-level API capabilities, such
as layer_dense(), match(), and keras_model(), minimal to no modifications
are required. Nevertheless there’s a lengthy tail of small modifications that you simply
would possibly must make when updating code that made use of the lower-level
Keras API. A few of these are documented right here:
https://keras.io/guides/migrating_to_keras_3/.

For those who’re working into points or have questions on updating, don’t
hesitate to ask on or
https://github.com/rstudio/keras/discussions.

The {keras} and {keras3} packages will coexist whereas the group
transitions. Throughout the transition, {keras} will proceed to obtain
patch updates for compatibility with Keras v2, which continues to be
revealed to PyPi beneath the package deal title tf-keras. After tf-keras is
now not maintained, the {keras} package deal might be archived.

Abstract

In abstract, {keras3} is a strong replace to the Keras R package deal,
incorporating new options whereas preserving the benefit of use and
performance of the unique. The brand new multi-backend assist,
complete suite of Ops capabilities, refined mannequin serialization API,
and up to date documentation workflows allow customers to simply take
benefit of the newest developments within the deep studying group.

Whether or not you’re a seasoned Keras consumer or simply beginning your deep
studying journey, Keras 3 supplies the instruments and adaptability to construct,
practice, and deploy fashions with ease and confidence. As we transition from
Keras 2 to Keras 3, we’re dedicated to supporting the group and
guaranteeing a easy migration. We invite you to discover the brand new options,
try the up to date documentation, and be a part of the dialog on our
GitHub discussions web page. Welcome to the following chapter of deep studying in
R with Keras 3!