defmodule Axon do
@moduledoc """
A high-level interface for creating neural network models.
Axon is built entirely on top of Nx numerical definitions,
so every neural network can be JIT or AOT compiled using
any Nx compiler, or even transformed into high-level neural
network formats like TensorFlow Lite and
[ONNX](https://github.com/elixir-nx/axon_onnx).
For a more in-depth overview of Axon, refer to the [Guides](guides.html).
## Model Creation
All Axon models start with an input layer, optionally specifying
the expected shape of the input data:
input = Axon.input("input", shape: {nil, 784})
Notice you can specify some dimensions as `nil`, indicating
that the dimension size will be filled in at model runtime.
You can then compose inputs with other layers:
model =
input
|> Axon.dense(128, activation: :relu)
|> Axon.batch_norm()
|> Axon.dropout(rate: 0.8)
|> Axon.dense(64)
|> Axon.tanh()
|> Axon.dense(10)
|> Axon.activation(:softmax)
You can inspect the model for a nice summary:
IO.inspect(model)
#Axon<
inputs: %{"input" => {nil, 784}}
outputs: "softmax_0"
nodes: 9
>
Or use the `Axon.Display` module to see more in-depth summaries:
Axon.Display.as_table(model, Nx.template({1, 784}, :f32)) |> IO.puts
+----------------------------------------------------------------------------------------------------------------+
| Model |
+=======================================+=============+==============+===================+=======================+
| Layer | Input Shape | Output Shape | Options | Parameters |
+=======================================+=============+==============+===================+=======================+
| input ( input ) | [] | {1, 784} | shape: {nil, 784} | |
| | | | optional: false | |
+---------------------------------------+-------------+--------------+-------------------+-----------------------+
| dense_0 ( dense["input"] ) | [{1, 784}] | {1, 128} | | kernel: f32[784][128] |
| | | | | bias: f32[128] |
+---------------------------------------+-------------+--------------+-------------------+-----------------------+
| relu_0 ( relu["dense_0"] ) | [{1, 128}] | {1, 128} | | |
+---------------------------------------+-------------+--------------+-------------------+-----------------------+
| batch_norm_0 ( batch_norm["relu_0"] ) | [{1, 128}] | {1, 128} | epsilon: 1.0e-5 | gamma: f32[128] |
| | | | channel_index: 1 | beta: f32[128] |
| | | | momentum: 0.1 | mean: f32[128] |
| | | | | var: f32[128] |
+---------------------------------------+-------------+--------------+-------------------+-----------------------+
| dropout_0 ( dropout["batch_norm_0"] ) | [{1, 128}] | {1, 128} | rate: 0.8 | |
+---------------------------------------+-------------+--------------+-------------------+-----------------------+
| dense_1 ( dense["dropout_0"] ) | [{1, 128}] | {1, 64} | | kernel: f32[128][64] |
| | | | | bias: f32[64] |
+---------------------------------------+-------------+--------------+-------------------+-----------------------+
| tanh_0 ( tanh["dense_1"] ) | [{1, 64}] | {1, 64} | | |
+---------------------------------------+-------------+--------------+-------------------+-----------------------+
| dense_2 ( dense["tanh_0"] ) | [{1, 64}] | {1, 10} | | kernel: f32[64][10] |
| | | | | bias: f32[10] |
+---------------------------------------+-------------+--------------+-------------------+-----------------------+
| softmax_0 ( softmax["dense_2"] ) | [{1, 10}] | {1, 10} | | |
+---------------------------------------+-------------+--------------+-------------------+-----------------------+
### Multiple Inputs
Creating a model with multiple inputs is as easy as declaring an
additional input in your Axon graph. Every input layer present in
the final Axon graph will be required to be passed as input at the
time of model execution.
inp1 = Axon.input("input_0", shape: {nil, 1})
inp2 = Axon.input("input_1", shape: {nil, 1})
# Both inputs will be used
model1 = Axon.add(inp1, inp2)
# Only inp2 will be used
model2 = Axon.add(inp2, inp2)
Axon graphs are immutable, which means composing and manipulating
an Axon graph creates an entirely new graph. Additionally, layer
names are lazily generated at model execution time. To avoid
non-deterministic input orderings and names, Axon requires each
input to have a unique binary identifier. You can then reference
inputs by name when passing to models at execution time:
inp1 = Axon.input("input_0", shape: {nil, 1})
inp2 = Axon.input("input_1", shape: {nil, 1})
model1 = Axon.add(inp1, inp2)
{init_fn, predict_fn} = Axon.build(model1)
params1 = init_fn.(Nx.template({1, 1}, {:f, 32}), %{})
# Inputs are referenced by name
predict_fn.(params1, %{"input_0" => x, "input_1" => y})
### Multiple Outputs
Nx offers robust [container](https://hexdocs.pm/nx/Nx.Container.html) support
which is extended to Axon. Axon allows you to wrap any valid Nx container
in a layer. Containers are most commonly used to structure outputs:
inp1 = Axon.input("input_0", shape: {nil, 1})
inp2 = Axon.input("input_1", shape: {nil, 1})
model = Axon.container(%{foo: inp1, bar: inp2})
Containers can be arbitrarily nested:
inp1 = Axon.input("input_0", shape: {nil, 1})
inp2 = Axon.input("input_1", shape: {nil, 1})
model = Axon.container({%{foo: {inp1, %{bar: inp2}}}})
You can even use custom structs which implement the container protocol:
inp1 = Axon.input("input_0", shape: {nil, 1})
inp2 = Axon.input("input_1", shape: {nil, 1})
model = Axon.container(%MyStruct{foo: inp1, bar: inp2})
### Custom Layers
If you find that Axon's built-in layers are insufficient for your needs,
you can create your own using the custom layer API. All of Axon's built-in
layers (aside from special ones such as `input`, `constant`, and `container`)
make use of this same API.
Axon layers are really just placeholders for Nx computations with trainable
parameters and possibly state. To define a custom layer, you just need to
define a `defn` implementation:
defn my_layer(x, weight, _opts \\ []) do
Nx.atan2(x, weight)
end
Notice the only stipulation is that your custom layer implementation must
accept at least 1 input and a list of options. At execution time, every
layer will be passed a `:mode` option which can be used to control behavior
at training and inference time.
Inputs to your custom layer can be either Axon graph inputs or trainable
parameters. You can pass Axon graph inputs as-is to a custom layer. To
declare trainable parameters, use `Axon.param/3`:
weight = Axon.param("weight", param_shape)
To create a custom layer, you "wrap" your implementation and inputs into
a layer using `Axon.layer`. You'll notice the API mirrors Elixir's `apply`:
def atan2_layer(%Axon{} = input) do
weight = Axon.param("weight", param_shape)
Axon.layer(&my_layer/3, [input, weight])
end
## Model Execution
Under the hood, Axon models are represented as Elixir structs. You
can initialize and apply models by building or compiling them with
`Axon.build/2` or `Axon.compile/4` and then calling the produced
initialization and predict functions:
{init_fn, predict_fn} = Axon.build(model)
init_fn.(Nx.template({1, 1}, {:f, 32}), %{})
predict_fn.(params, inputs)
You may either set the default JIT compiler or backend globally, or
pass a specific compiler to `Axon.build/2`:
EXLA.set_as_nx_default([:tpu, :cuda, :rocm, :host])
{init_fn, predict_fn} = Axon.build(model, compiler: EXLA, mode: :train)
init_fn.(Nx.template({1, 1}, {:f, 32}), %{})
predict_fn.(params, inputs)
`predict_fn` by default runs in inference mode, which performs certain
optimizations and removes layers such as dropout layers. If constructing
a training step using `Axon.predict/4` or `Axon.build/2`, be sure to specify
`mode: :train`.
## Model Training
Combining the Axon model creation API with the optimization and training
APIs, you can create and train neural networks with ease:
model =
Axon.input("input_0", shape: {nil, 784})
|> Axon.dense(128, activation: :relu)
|> Axon.layer_norm()
|> Axon.dropout()
|> Axon.dense(10, activation: :softmax)
IO.inspect model
model_state =
model
|> Axon.Loop.trainer(:categorical_cross_entropy, Axon.Optimizers.adamw(0.005))
|> Axon.Loop.run(train_data, epochs: 10, compiler: EXLA)
See `Axon.Updates` and `Axon.Loop` for a more in-depth treatment of
model optimization and model training.
## Using with `Nx.Serving`
When deploying an `Axon` model to production, you usually want to batch
multiple prediction requests and run the inference for all of them at
once. Conveniently, `Nx` already has an abstraction for this task in the
form of `Nx.Serving`. Here's how you could define a serving for an `Axon`
model:
def build_serving() do
# Configuration
batch_size = 4
defn_options = [compiler: EXLA]
Nx.Serving.new(
# This function runs on the serving startup
fn ->
# Build the Axon model and load params (usually from file)
model = build_model()
params = load_params()
# Build the prediction defn function
{_init_fun, predict_fun} = Axon.build(model)
inputs_template = %{"pixel_values" => Nx.template({batch_size, 224, 224, 3}, :f32)}
template_args = [Nx.to_template(params), inputs_template]
# Compile the prediction function upfront for the configured batch_size
predict_fun = Nx.Defn.compile(predict_fun, template_args, defn_options)
# The returned function is called for every accumulated batch
fn inputs ->
inputs = Nx.Batch.pad(inputs, batch_size - inputs.size)
predict_fun.(params, inputs)
end
end,
batch_size: batch_size
)
end
Then you would start the serving server as part of your application's
supervision tree:
children = [
...,
{Nx.Serving, serving: build_serving(), name: MyApp.Serving, batch_timeout: 100}
]
With that in place, you can now ask serving for predictions all across
your application (controllers, live views, async jobs, etc.). Having a
tensor input you would do:
inputs = %{"pixel_values" => ...}
batch = Nx.Batch.concatenate([inputs])
result = Nx.Serving.batched_run(MyApp.Serving, batch)
Usually you also want to do pre/post-processing of the model input/output.
You could make those preparations directly before/after `Nx.Serving.batched_run/2`,
however you can also make use of `Nx.Serving.client_preprocessing/2` and
`Nx.Serving.client_postprocessing/2` to encapsulate that logic as part of
the serving.
"""
alias __MODULE__, as: Axon
alias Axon.Parameter
require Logger
# Axon serialization version
@file_version 1
@type t :: %__MODULE__{}
defstruct [
:nodes,
:output
]
@doc """
Custom Axon layer with given inputs.
Inputs may be other Axon layers or trainable parameters created
with `Axon.param`. At inference time, `op` will be applied with
inputs in specified order and an additional `opts` parameter which
specifies inference options. All options passed to layer are forwarded
to inference function except:
* `:name` - layer name.
* `:op_name` - layer operation for inspection and building parameter map.
* `:mode` - if the layer should run only on `:inference` or `:train`. Defaults to `:both`
Note this means your layer should not use these as input options,
as they will always be dropped during inference compilation.
Axon's compiler will additionally forward the following options to
every layer at inference time:
* `:mode` - `:inference` or `:train`. To control layer behavior
based on inference or train time.
`op` is a function of the form:
fun = fn input, weight, bias, _opts ->
input * weight + bias
end
"""
@doc type: :special
def layer(op, inputs, opts \\ []) when (is_atom(op) or is_function(op)) and is_list(inputs) do
{inputs, params, args, updated_nodes} = split_inputs(op, inputs)
inputs = Enum.reverse(inputs)
params = Enum.reverse(params)
args = Enum.reverse(args)
{mode, opts} = Keyword.pop(opts, :mode, :both)
{name, opts} = Keyword.pop(opts, :name)
{op_name, opts} = Keyword.pop(opts, :op_name, :custom)
name = name(op_name, name)
id = System.unique_integer([:positive, :monotonic])
axon_node = make_node(id, op, name, op_name, mode, inputs, params, args, opts)
%Axon{output: id, nodes: Map.put(updated_nodes, id, axon_node)}
end
defp make_node(id, op, name, op_name, mode, inputs, params, args, layer_opts) do
{:current_stacktrace, [_process_info, _axon_layer | stacktrace]} =
Process.info(self(), :current_stacktrace)
%Axon.Node{
id: id,
mode: mode,
name: name,
parent: inputs,
parameters: params,
args: args,
op: op,
policy: Axon.MixedPrecision.create_policy(),
hooks: [],
opts: layer_opts,
op_name: op_name,
stacktrace: stacktrace
}
end
defp split_inputs(:container, [inputs]) do
{inputs, cache} =
deep_map_reduce(inputs, %{}, fn %Axon{output: id, nodes: nodes}, cache ->
{id, Map.merge(nodes, cache)}
end)
{[inputs], [], [:layer], cache}
end
defp split_inputs(_op, inputs) do
Enum.reduce(inputs, {[], [], [], %{}}, fn
%Axon{output: layer_input, nodes: nodes}, {layers, params, args, cache} ->
{[layer_input | layers], params, [:layer | args], Map.merge(nodes, cache)}
%Parameter{} = param, {layers, params, args, cache} ->
{layers, [param | params], [:parameter | args], cache}
invalid, _ ->
raise ArgumentError, "invalid input given to layer: #{inspect(invalid)}"
end)
end
@doc """
Trainable Axon parameter used to create custom layers.
Parameters are specified in usages of `Axon.layer` and will
be automatically initialized and used in subsequent applications
of Axon models.
Parameters *must* be specified in order of their usage.
## Options
* `:initializer` - parameter initializer. Defaults to `:glorot_uniform`.
"""
@doc type: :special
def param(name, shape, opts \\ [])
when is_binary(name) and (is_tuple(shape) or is_function(shape)) do
opts = Keyword.validate!(opts, initializer: :glorot_uniform, type: {:f, 32})
initializer = validate_initializer!(opts[:initializer])
type = opts[:type] || {:f, 32}
%Axon.Parameter{
name: name,
shape: shape,
type: type,
initializer: initializer
}
end
@doc """
Adds an input layer to the network.
Input layers specify a model's inputs. Input layers are
always the root layers of the neural network.
You must specify the input layers name, which will be used
to uniquely identify it in the case of multiple inputs.
## Options
* `:shape` - the expected input shape, use `nil` for dimensions
of a dynamic size.
* `:optional` - if `true`, the input may be omitted when using
the model. This needs to be handled in one of the subsequent
layers. See `optional/2` for more details.
"""
@doc type: :special
def input(name, opts \\ [])
def input(name, opts) when is_binary(name) and is_list(opts) do
opts = Keyword.validate!(opts, [:shape, optional: false])
optional = opts[:optional]
input_shape = opts[:shape]
output_shape = input_shape && Axon.Shape.input(input_shape)
layer(:input, [], name: name, shape: output_shape, op_name: :input, optional: optional)
end
# TODO: remove on Axon v0.3
def input(input_shape, name) when is_binary(name) do
IO.warn(
"Passing shape as an argument to Axon.input/2 is deprecated, pass it as an option instead"
)
input(name, [{:shape, input_shape}])
end
@deprecated "Pass the shape as an option to Axon.input/2"
def input(input_shape, name, opts) when is_binary(name) do
input(name, [{:shape, input_shape} | opts])
end
@doc """
Wraps an Axon model in an optional node.
By default, when an optional input is missing, all subsequent layers
are nullified. For example, consider this model:
values = Axon.input("values")
mask = Axon.input("mask", optional: true)
model =
values
|> Axon.dense(10)
|> Axon.multiply(mask)
|> Axon.dense(1)
|> Axon.sigmoid()
In case the mask is not provided, the input node will resolve to
`%Axon.None{}` and so will all the layers that depend on it. By
using `optional/2` a layer may opt-in to receive `%Axon.None{}`.
To fix our example, we could define a custom layer to apply the
mask only when present
def apply_optional_mask(%Axon{} = x, %Axon{} = mask) do
Axon.layer(
fn x, mask, _opts ->
case mask do
%Axon.None{} -> x
mask -> Nx.multiply(x, mask)
end
end,
[x, Axon.optional(mask)]
)
end
# ...
model =
values
|> Axon.dense(10)
|> apply_optional_mask(mask)
|> Axon.dense(1)
|> Axon.sigmoid()
## Options
* `:name` - layer name.
"""
@doc type: :special
def optional(%Axon{} = x, opts \\ []) do
opts = Keyword.validate!(opts, [:name])
layer(:optional, [x], name: opts[:name], op_name: :optional)
end
@doc """
Adds a constant layer to the network.
Constant layers encapsulate Nx tensors in an Axon layer for ease
of use with other Axon layers. They can be used interchangeably
with other Axon layers:
inp = Axon.input("input", shape: {nil, 32})
my_constant = Axon.constant(Nx.iota({1, 32}))
model = Axon.add(inp, my_constant)
Constant layers will be cast according to the mixed precision policy.
If it's important for your constant to retain it's type during
the computation, you will need to set the mixed precision policy to
ignore constant layers.
## Options
* `:name` - layer name.
"""
def constant(tensor, opts \\ [])
@doc type: :special
def constant(%Nx.Tensor{} = tensor, opts) do
opts = Keyword.validate!(opts, [:name])
layer(:constant, [], name: opts[:name], value: tensor, op_name: :constant)
end
def constant(number, opts) when is_number(number) do
opts = Keyword.validate!(opts, [:name])
layer(:constant, [], name: opts[:name], value: Nx.tensor(number), op_name: :constant)
end
def constant(value, _) do
raise ArgumentError,
"value passed to constant must be an Nx tensor" <>
" but got #{inspect(value)}, if you are passing" <>
" a number, wrap it with a call to Nx.tensor/2"
end
@doc """
Adds a container layer to the network.
In certain cases you may want your model to have multiple
outputs. In order to make this work, you must "join" the
outputs into an Axon layer using this function for use in
initialization and inference later on.
The given container can be any valid Axon Nx container.
## Options
* `:name` - layer name.
## Examples
iex> inp1 = Axon.input("input_0", shape: {nil, 1})
iex> inp2 = Axon.input("input_1", shape: {nil, 2})
iex> model = Axon.container(%{a: inp1, b: inp2})
iex> %{a: a, b: b} = Axon.predict(model, %{}, %{
...> "input_0" => Nx.tensor([[1.0]]),
...> "input_1" => Nx.tensor([[1.0, 2.0]])
...> })
iex> a
#Nx.Tensor<
f32[1][1]
[
[1.0]
]
>
iex> b
#Nx.Tensor<
f32[1][2]
[
[1.0, 2.0]
]
>
"""
@doc type: :special
def container(container, opts \\ []) do
opts = Keyword.validate!(opts, [:name])
layer(:container, [container], name: opts[:name], op_name: :container)
end
# TODO: This should not be duplicated
defp deep_new(%Nx.Tensor{} = x, fun), do: fun.(x)
defp deep_new(x, fun) when is_number(x), do: fun.(x)
defp deep_new(map, fun) do
{cont, :ok} = Nx.Container.traverse(map, :ok, &recur_traverse(&1, &2, fun))
cont
end
defp recur_traverse(item, :ok, fun) do
case item do
%Axon{} = t ->
{fun.(t), :ok}
%{axon: :axon} = t ->
{fun.(t), :ok}
container ->
{deep_new(container, fun), :ok}
end
end
defp deep_merge(left, right, fun) do
case Nx.Container.traverse(left, leaves(right), &recur_merge(&1, &2, fun)) do
{merged, []} ->
merged
{_merged, _leftover} ->
raise ArgumentError,
"unable to merge arguments with incompatible" <>
" structure"
end
end
defp leaves(container) do
container
|> Nx.Container.reduce([], fn x, acc -> [x | acc] end)
|> Enum.reverse()
end
defp recur_merge(left, [right | right_leaves], fun) do
case {left, right} do
{%Nx.Tensor{} = left, %Nx.Tensor{} = right} ->
{fun.(left, right), right_leaves}
{%Axon{} = left, %Axon{} = right} ->
{fun.(left, right), right_leaves}
{left, right} ->
{deep_merge(left, right, fun), right_leaves}
end
end
@doc """
Wraps an Axon model into a namespace.
A namespace is a part of an Axon model which is meant to
be a self-contained collection of Axon layers. Namespaces
are guaranteed to always generate with the same internal
layer names and can be re-used universally across models.
Namespaces are most useful for containing large collections
of layers and offering a straightforward means for accessing
the parameters of individual model components. A common application
of namespaces is to use them in with a pre-trained model for
fine-tuning:
{base, resnet_params} = resnet()
base = base |> Axon.namespace("resnet")
model = base |> Axon.dense(1)
{init_fn, predict_fn} = Axon.build(model)
init_fn.(Nx.template({1, 3, 224, 224}, {:f, 32}), %{"resnset" => resnet_params})
Notice you can use `init_fn` in conjunction with namespaces
to specify which portion of a model you'd like to initialize
from a fixed starting point.
Namespaces have fixed names, which means it's easy to run into namespace
collisions. Re-using namespaces, re-using inner parts of a namespace,
and attempting to share layers between namespaces are still sharp
edges in namespace usage.
"""
@doc type: :special
def namespace(%Axon{} = axon, name) when is_binary(name) do
layer(:namespace, [axon], name: name)
end
@doc """
Adds a dense layer to the network.
The dense layer implements:
output = activation(dot(input, kernel) + bias)
where `activation` is given by the `:activation` option and both
`kernel` and `bias` are layer parameters. `units` specifies the
number of output units.
Compiles to `Axon.Layers.dense/4`.
## Options
* `:name` - layer name.
* `:kernel_initializer` - initializer for `kernel` weights.
Defaults to `:glorot_uniform`.
* `:bias_initializer` - initializer for `bias` weights. Defaults
to `:zeros`.
* `:activation` - element-wise activation function.
* `:use_bias` - whether the layer should add bias to the output.
Defaults to `true`.
"""
@doc type: :linear
def dense(%Axon{} = x, units, opts \\ [])
when is_integer(units) and units > 0 do
opts =
Keyword.validate!(opts, [
:name,
:activation,
kernel_initializer: :glorot_uniform,
bias_initializer: :zeros,
use_bias: true
])
kernel_shape = &Axon.Shape.dense_kernel(&1, units)
bias_shape = &Axon.Shape.dense_bias(&1, units)
kernel = param("kernel", kernel_shape, initializer: opts[:kernel_initializer])
{inputs, op} =
if opts[:use_bias] do
bias = param("bias", bias_shape, initializer: opts[:bias_initializer])
{[x, kernel, bias], :dense}
else
{[x, kernel], :dense}
end
node = layer(op, inputs, name: opts[:name], op_name: :dense)
if activation = opts[:activation] do
activation(node, activation)
else
node
end
end
@doc """
Adds a bilinear layer to the network.
The bilinear layer implements:
output = activation(dot(dot(input1, kernel), input2) + bias)
where `activation` is given by the `:activation` option and both
`kernel` and `bias` are layer parameters. `units` specifies the
number of output units.
All dimensions but the last of `input1` and `input2` must match. The
batch sizes of both inputs must also match or at least one must be `nil`.
Inferred output batch size coerces to the strictest input batch size.
Compiles to `Axon.Layers.bilinear/5`.
## Options
* `:name` - layer name.
* `:kernel_initializer` - initializer for `kernel` weights.
Defaults to `:glorot_uniform`.
* `:bias_initializer` - initializer for `bias` weights. Defaults
to `:zeros`.
* `:activation` - element-wise activation function.
* `:use_bias` - whether the layer should add bias to the output.
Defaults to `true`.
"""
@doc type: :linear
def bilinear(
%Axon{} = input1,
%Axon{} = input2,
units,
opts \\ []
)
when is_integer(units) and units > 0 do
opts =
Keyword.validate!(opts, [
:name,
:activation,
kernel_initializer: :glorot_uniform,
bias_initializer: :zeros,
use_bias: true
])
kernel_shape = &Axon.Shape.bilinear_kernel(&1, &2, units)
bias_shape = &Axon.Shape.bilinear_bias(&1, &2, units)
kernel = param("kernel", kernel_shape, initializer: opts[:kernel_initializer])
{inputs, op} =
if opts[:use_bias] do
bias = param("bias", bias_shape, initializer: opts[:bias_initializer])
{[input1, input2, kernel, bias], :bilinear}
else
{[input1, input2, kernel], :bilinear}
end
node = layer(op, inputs, name: opts[:name], op_name: :bilinear)
if activation = opts[:activation] do
activation(node, activation)
else
node
end
end
@doc """
Adds a convolution layer to the network.
The convolution layer implements a general dimensional
convolutional layer - which convolves a kernel over the input
to produce an output.
Compiles to `Axon.Layers.conv/4`.
## Options
* `:name` - layer name.
* `:kernel_initializer` - initializer for `kernel` weights.
Defaults to `:glorot_uniform`.
* `:bias_initializer` - initializer for `bias` weights. Defaults
to `:zeros`
* `:activation` - element-wise activation function.
* `:use_bias` - whether the layer should add bias to the output.
Defaults to `true`
* `:kernel_size` - size of the kernel spatial dimensions. Defaults
to `1`.
* `:strides` - stride during convolution. Defaults to `1`.
* `:padding` - padding to the spatial dimensions of the input.
Defaults to `:valid`.
* `:input_dilation` - dilation to apply to input. Defaults to `1`.
* `:kernel_dilation` - dilation to apply to kernel. Defaults to `1`.
* `:feature_group_size` - feature group size for convolution. Defaults
to `1`.
* `:channels` - channels location. One of `:first` or `:last`.
Defaults to `:last`.
"""
@doc type: :convolution
def conv(%Axon{} = x, units, opts \\ [])
when is_integer(units) and units > 0 do
opts =
Keyword.validate!(opts, [
:name,
:activation,
kernel_initializer: :glorot_uniform,
bias_initializer: :zeros,
use_bias: true,
kernel_size: 1,
strides: 1,
padding: :valid,
input_dilation: 1,
kernel_dilation: 1,
channels: :last,
feature_group_size: 1
])
kernel_size = opts[:kernel_size]
strides = opts[:strides]
padding = opts[:padding]
input_dilation = opts[:input_dilation]
kernel_dilation = opts[:kernel_dilation]
channels = opts[:channels]
feature_group_size = opts[:feature_group_size]
kernel_shape = &Axon.Shape.conv_kernel(&1, units, kernel_size, channels, feature_group_size)
bias_shape = &Axon.Shape.conv_bias(&1, units, kernel_size, channels, feature_group_size)
kernel = param("kernel", kernel_shape, initializer: opts[:kernel_initializer])
{inputs, op} =
if opts[:use_bias] do
bias = param("bias", bias_shape, initializer: opts[:bias_initializer])
{[x, kernel, bias], :conv}
else
{[x, kernel], :conv}
end
node =
layer(op, inputs,
name: opts[:name],
strides: strides,
padding: padding,
input_dilation: input_dilation,
kernel_dilation: kernel_dilation,
feature_group_size: feature_group_size,
channels: channels,
op_name: :conv
)
if activation = opts[:activation] do
activation(node, activation)
else
node
end
end
@doc """
Adds a transposed convolution layer to the network.
The transposed convolution layer is sometimes referred to as a
fractionally strided convolution or (incorrectly) as a deconvolution.
Compiles to `Axon.Layers.conv_transpose/4`.
## Options
* `:name` - layer name.
* `:kernel_initializer` - initializer for `kernel` weights.
Defaults to `:glorot_uniform`.
* `:bias_initializer` - initializer for `bias` weights. Defaults
to `:zeros`
* `:activation` - element-wise activation function.
* `:use_bias` - whether the layer should add bias to the output.
Defaults to `true`
* `:kernel_size` - size of the kernel spatial dimensions. Defaults
to `1`.
* `:strides` - stride during convolution. Defaults to `1`.
* `:padding` - padding to the spatial dimensions of the input.
Defaults to `:valid`.
* `:kernel_dilation` - dilation to apply to kernel. Defaults to `1`.
* `:channels` - channels location. One of `:first` or `:last`.
Defaults to `:last`.
"""
@doc type: :convolution
def conv_transpose(%Axon{} = x, units, opts \\ []) do
opts =
Keyword.validate!(opts, [
:name,
:activation,
kernel_initializer: :glorot_uniform,
bias_initializer: :zeros,
use_bias: true,
kernel_size: 1,
strides: 1,
padding: :valid,
kernel_dilation: 1,
channels: :last
])
kernel_size = opts[:kernel_size]
strides = opts[:strides]
padding = opts[:padding]
kernel_dilation = opts[:kernel_dilation]
channels = opts[:channels]
kernel_shape = &Axon.Shape.conv_kernel(&1, units, kernel_size, channels, 1)
bias_shape = &Axon.Shape.conv_bias(&1, units, kernel_size, channels, 1)
kernel = param("kernel", kernel_shape, initializer: opts[:kernel_initializer])
{inputs, op} =
if opts[:use_bias] do
bias = param("bias", bias_shape, initializer: opts[:bias_initializer])
{[x, kernel, bias], :conv_transpose}
else
{[x, kernel], :conv_transpose}
end
node =
layer(op, inputs,
name: opts[:name],
strides: strides,
padding: padding,
kernel_dilation: kernel_dilation,
channels: channels,
op_name: :conv_transpose
)
if activation = opts[:activation] do
activation(node, activation)
else
node
end
end
@doc """
Adds a depthwise convolution layer to the network.
The depthwise convolution layer implements a general
dimensional depthwise convolution - which is a convolution
where the feature group size is equal to the number of
input channels.
Channel multiplier grows the input channels by the given
factor. An input factor of 1 means the output channels
are the same as the input channels.
Compiles to `Axon.Layers.depthwise_conv/4`.
## Options
* `:name` - layer name.
* `:kernel_initializer` - initializer for `kernel` weights.
Defaults to `:glorot_uniform`.
* `:bias_initializer` - initializer for `bias` weights. Defaults
to `:zeros`
* `:activation` - element-wise activation function.
* `:use_bias` - whether the layer should add bias to the output.
Defaults to `true`
* `:kernel_size` - size of the kernel spatial dimensions. Defaults
to `1`.
* `:strides` - stride during convolution. Defaults to `1`.
* `:padding` - padding to the spatial dimensions of the input.
Defaults to `:valid`.
* `:input_dilation` - dilation to apply to input. Defaults to `1`.
* `:kernel_dilation` - dilation to apply to kernel. Defaults to `1`.
* `:channels` - channels location. One of `:first` or `:last`.
Defaults to `:last`.
"""
@doc type: :convolution
def depthwise_conv(%Axon{} = x, channel_multiplier, opts \\ [])
when is_integer(channel_multiplier) and channel_multiplier >= 1 do
opts =
Keyword.validate!(opts, [
:name,
:activation,
kernel_initializer: :glorot_uniform,
bias_initializer: :zeros,
use_bias: true,
kernel_size: 1,
strides: 1,
padding: :valid,
input_dilation: 1,
kernel_dilation: 1,
channels: :last
])
kernel_size = opts[:kernel_size]
strides = opts[:strides]
padding = opts[:padding]
input_dilation = opts[:input_dilation]
kernel_dilation = opts[:kernel_dilation]
channels = opts[:channels]
kernel_shape =
&Axon.Shape.depthwise_conv_kernel(&1, channel_multiplier, kernel_size, channels)
bias_shape = &Axon.Shape.depthwise_conv_bias(&1, channel_multiplier, kernel_size, channels)
kernel = param("kernel", kernel_shape, initializer: opts[:kernel_initializer])
{inputs, op} =
if opts[:use_bias] do
bias = param("bias", bias_shape, initializer: opts[:bias_initializer])
{[x, kernel, bias], :depthwise_conv}
else
{[x, kernel], :depthwise_conv}
end
node =
layer(op, inputs,
name: opts[:name],
strides: strides,
padding: padding,
input_dilation: input_dilation,
kernel_dilation: kernel_dilation,
channels: channels,
op_name: :depthwise_conv
)
if activation = opts[:activation] do
activation(node, activation)
else
node
end
end
@doc """
Adds a depthwise separable 2-dimensional convolution to the
network.
Depthwise separable convolutions break the kernel into kernels
for each dimension of the input and perform a depthwise conv
over the input with each kernel.
Compiles to `Axon.Layers.separable_conv2d/6`.
## Options
* `:name` - layer name.
* `:kernel_initializer` - initializer for `kernel` weights.
Defaults to `:glorot_uniform`.
* `:bias_initializer` - initializer for `bias` weights. Defaults
to `:zeros`
* `:activation` - element-wise activation function.
* `:use_bias` - whether the layer should add bias to the output.
Defaults to `true`
* `:kernel_size` - size of the kernel spatial dimensions. Defaults
to `1`.
* `:strides` - stride during convolution. Defaults to `1`.
* `:padding` - padding to the spatial dimensions of the input.
Defaults to `:valid`.
* `:input_dilation` - dilation to apply to input. Defaults to `1`.
* `:kernel_dilation` - dilation to apply to kernel. Defaults to `1`.
* `:channels` - channels location. One of `:first` or `:last`.
Defaults to `:last`.
"""
@doc type: :convolution
def separable_conv2d(%Axon{} = x, channel_multiplier, opts \\ [])
when is_integer(channel_multiplier) and channel_multiplier >= 1 do
opts =
Keyword.validate!(opts, [
:name,
:activation,
kernel_initializer: :glorot_uniform,
bias_initializer: :zeros,
use_bias: true,
kernel_size: 1,
strides: 1,
padding: :valid,
input_dilation: 1,
kernel_dilation: 1,
channels: :last
])
kernel_size = opts[:kernel_size]
strides = opts[:strides]
padding = opts[:padding]
input_dilation = opts[:input_dilation]
kernel_dilation = opts[:kernel_dilation]
channels = opts[:channels]
k1_shape =
&Axon.Shape.separable_conv2d_kernel(
&1,
channel_multiplier,
kernel_size,
1,
channels
)
k2_shape =
&Axon.Shape.separable_conv2d_kernel(
&1,
channel_multiplier,
kernel_size,
2,
channels
)
b1_shape = &Axon.Shape.separable_conv2d_bias(&1, channel_multiplier, kernel_size, channels)
b2_shape = &Axon.Shape.separable_conv2d_bias(&1, channel_multiplier, kernel_size, channels)
kernel_initializer = opts[:kernel_initializer]
k1 = param("kernel_1", k1_shape, initializer: kernel_initializer)
k2 = param("kernel_2", k2_shape, initializer: kernel_initializer)
{inputs, op} =
if opts[:use_bias] do
bias_initializer = opts[:bias_initializer]
b1 = param("bias_1", b1_shape, initializer: bias_initializer)
b2 = param("bias_2", b2_shape, initializer: bias_initializer)
{[x, k1, b1, k2, b2], :separable_conv2d}
else
{[x, k1, k2], :separable_conv2d}
end
node =
layer(
op,
inputs,
name: opts[:name],
strides: strides,
padding: padding,
input_dilation: input_dilation,
kernel_dilation: kernel_dilation,
channels: channels,
op_name: :separable_conv2d
)
if activation = opts[:activation] do
activation(node, activation)
else
node
end
end
@doc """
Adds a depthwise separable 3-dimensional convolution to the
network.
Depthwise separable convolutions break the kernel into kernels
for each dimension of the input and perform a depthwise conv
over the input with each kernel.
Compiles to `Axon.Layers.separable_conv3d/8`.
## Options
* `:name` - layer name.
* `:kernel_initializer` - initializer for `kernel` weights.
Defaults to `:glorot_uniform`.
* `:bias_initializer` - initializer for `bias` weights. Defaults
to `:zeros`
* `:activation` - element-wise activation function.
* `:use_bias` - whether the layer should add bias to the output.
Defaults to `true`
* `:kernel_size` - size of the kernel spatial dimensions. Defaults
to `1`.
* `:strides` - stride during convolution. Defaults to `1`.
* `:padding` - padding to the spatial dimensions of the input.
Defaults to `:valid`.
* `:input_dilation` - dilation to apply to input. Defaults to `1`.
* `:kernel_dilation` - dilation to apply to kernel. Defaults to `1`.
* `:channels` - channels location. One of `:first` or `:last`.
Defaults to `:last`.
"""
@doc type: :convolution
def separable_conv3d(%Axon{} = x, channel_multiplier, opts \\ [])
when is_integer(channel_multiplier) and channel_multiplier >= 1 do
opts =
Keyword.validate!(opts, [
:name,
:activation,
kernel_initializer: :glorot_uniform,
bias_initializer: :zeros,
use_bias: true,
kernel_size: 1,
strides: 1,
padding: :valid,
input_dilation: 1,
kernel_dilation: 1,
channels: :last
])
kernel_size = opts[:kernel_size]
strides = opts[:strides]
padding = opts[:padding]
input_dilation = opts[:input_dilation]
kernel_dilation = opts[:kernel_dilation]
channels = opts[:channels]
k1_shape =
&Axon.Shape.separable_conv3d_kernel(
&1,
channel_multiplier,
kernel_size,
1,
channels
)
k2_shape =
&Axon.Shape.separable_conv3d_kernel(
&1,
channel_multiplier,
kernel_size,
2,
channels
)
k3_shape =
&Axon.Shape.separable_conv3d_kernel(
&1,
channel_multiplier,
kernel_size,
3,
channels
)
b1_shape = &Axon.Shape.separable_conv3d_bias(&1, channel_multiplier, kernel_size, channels)
b2_shape = &Axon.Shape.separable_conv3d_bias(&1, channel_multiplier, kernel_size, channels)
b3_shape = &Axon.Shape.separable_conv3d_bias(&1, channel_multiplier, kernel_size, channels)
kernel_initializer = opts[:kernel_initializer]
k1 = param("kernel_1", k1_shape, initializer: kernel_initializer)
k2 = param("kernel_2", k2_shape, initializer: kernel_initializer)
k3 = param("kernel_3", k3_shape, initializer: kernel_initializer)
{inputs, op} =
if opts[:use_bias] do
bias_initializer = opts[:bias_initializer]
b1 = param("bias_1", b1_shape, initializer: bias_initializer)
b2 = param("bias_2", b2_shape, initializer: bias_initializer)
b3 = param("bias_3", b3_shape, initializer: bias_initializer)
{[x, k1, b1, k2, b2, k3, b3], :separable_conv3d}
else
{[x, k1, k2, k3], :separable_conv3d}
end
node =
layer(
op,
inputs,
name: opts[:name],
strides: strides,
padding: padding,
input_dilation: input_dilation,
kernel_dilation: kernel_dilation,
channels: channels,
op_name: :separable_conv3d
)
if activation = opts[:activation] do
activation(node, activation)
else
node
end
end
@activation_layers [
{:celu, "Continuously-differentiable exponential linear unit", "a"},
{:elu, "Exponential linear unit", "an"},
{:exp, "Exponential", "an"},
{:gelu, "Gaussian error linear unit", "a"},
{:hard_sigmoid, "Hard sigmoid", "a"},
{:hard_silu, "Hard sigmoid weighted linear unit", "a"},
{:hard_tanh, "Hard hyperbolic tangent", "a"},
{:leaky_relu, "Leaky rectified linear unit", "a"},
{:linear, "Linear", "a"},
{:log_sumexp, "Log-sumexp", "a"},
{:log_sigmoid, "Log-sigmoid", "a"},
{:log_softmax, "Log-softmax", "a"},
{:mish, "Mish", "a"},
{:relu, "Rectified linear unit", "a"},
{:relu6, "Rectified linear unit 6", "a"},
{:sigmoid, "Sigmoid", "a"},
{:silu, "Sigmoid weighted linear unit", "a"},
{:selu, "Scaled exponential linear unit", "a"},
{:softmax, "Softmax", "a"},
{:softplus, "Softplus", "a"},
{:softsign, "Softsign", "a"},
{:tanh, "Hyperbolic tangent", "a"}
]
@doc """
Adds an activation layer to the network.
Activation layers are element-wise functions typically called
after the output of another layer.
## Options
* `:name` - layer name.
"""
@doc type: :activation
def activation(x, activation, opts \\ [])
def activation(%Axon{} = x, activation, opts) when is_atom(activation) do
opts = opts ++ [op_name: activation]
layer(activation, [x], opts)
end
def activation(%Axon{} = x, activation, opts)
when is_function(activation) do
layer(activation, [x], opts)
end
## Activation
for {activation, name, a_or_an} <- @activation_layers do
@doc """
Adds #{a_or_an} #{name} activation layer to the network.
See `Axon.Activations.#{Atom.to_string(activation)}/1` for more details.
## Options
* `:name` - layer name.
"""
@doc type: :activation
def unquote(activation)(%Axon{} = x, opts \\ []) do
activation(x, unquote(activation), opts)
end
end
## Dropout
@dropout_layers [
{:dropout, "Dropout", "a"},
{:feature_alpha_dropout, "Feature alpha dropout", "a"},
{:spatial_dropout, "Spatial dropout", "a"},
{:alpha_dropout, "Alpha dropout", "an"}
]
for {dropout, name, a_or_an} <- @dropout_layers do
@doc """
Adds #{a_or_an} #{name} layer to the network.
See `Axon.Layers.#{Atom.to_string(dropout)}/2` for more details.
## Options
* `:name` - layer name.
* `:rate` - dropout rate. Defaults to `0.5`.
Needs to be equal or greater than zero and less than one.
"""
@doc type: :dropout
def unquote(dropout)(%Axon{} = x, opts \\ []) do
dropout(x, unquote(dropout), opts)
end
end
defp dropout(%Axon{} = x, dropout, opts) do
opts = Keyword.validate!(opts, [:name, :seed, rate: 0.5])
seed = Keyword.get_lazy(opts, :seed, fn -> :erlang.system_time() end)
if opts[:rate] < 0 or opts[:rate] >= 1 do
raise ArgumentError,
"The dropout rate needs to be >= 0 and < 1, got #{inspect(opts[:rate])}"
end
key_state =
param("key", fn _ -> {2} end,
type: {:u, 32},
initializer: fn _, _ -> Nx.Random.key(seed) end
)
layer(dropout, [x, key_state],
name: opts[:name],
rate: opts[:rate],
op_name: dropout,
mode: :train
)
end
## Pooling
@pooling_layers [
{:max_pool, "Max pool", "a"},
{:avg_pool, "Average pool", "an"},
{:lp_pool, "Power average pool", "a"}
]
for {pool, name, a_or_an} <- @pooling_layers do
@doc """
Adds #{a_or_an} #{name} layer to the network.
See `Axon.Layers.#{Atom.to_string(pool)}/2` for more details.
## Options
* `:name` - layer name.
* `:kernel_size` - size of the kernel spatial dimensions. Defaults
to `1`.
* `:strides` - stride during convolution. Defaults to size of kernel.
* `:padding` - padding to the spatial dimensions of the input.
Defaults to `:valid`.
* `:dilations` - window dilations. Defaults to `1`.
* `:channels` - channels location. One of `:first` or `:last`.
Defaults to `:last`.
"""
@doc type: :pooling
def unquote(pool)(%Axon{} = x, opts \\ []) do
pool(x, unquote(pool), opts)
end
end
defp pool(%Axon{} = x, pool, opts) do
opts =
Keyword.validate!(opts, [
:name,
:strides,
kernel_size: 1,
padding: :valid,
channels: :last,
dilations: 1,
norm: 2
])
kernel_size = opts[:kernel_size]
strides = opts[:strides]
padding = opts[:padding]
channels = opts[:channels]
dilations = opts[:dilations]
name = opts[:name]
opts =
if pool == :lp_pool do
norm = opts[:norm]
[
name: name,
kernel_size: kernel_size,
strides: strides,
padding: padding,
channels: channels,
window_dilations: dilations,
norm: norm,
op_name: pool
]
else
[
name: name,
kernel_size: kernel_size,
strides: strides,
padding: padding,
channels: channels,
window_dilations: dilations,
op_name: pool
]
end
layer(pool, [x], opts)
end
## Adaptive Pooling
@adaptive_pooling_layers [
{:adaptive_avg_pool, "Adaptive average pool", "an"},
{:adaptive_max_pool, "Adaptive max pool", "an"},
{:adaptive_lp_pool, "Adaptive power average pool", "an"}
]
for {pool, name, a_or_an} <- @adaptive_pooling_layers do
@doc """
Adds #{a_or_an} #{name} layer to the network.
See `Axon.Layers.#{Atom.to_string(pool)}/2` for more details.
## Options
* `:name` - layer name.
* `:output_size` - layer output size.
* `:channels` - channel configuration. One of `:first` or `:last`.
Defaults to `:last`.
"""
@doc type: :pooling
def unquote(pool)(%Axon{} = x, opts \\ []) do
adaptive_pool(x, unquote(pool), opts)
end
end
defp adaptive_pool(%Axon{} = x, pool, opts) do
opts = Keyword.validate!(opts, [:name, :output_size, channels: :last, norm: 2])
channels = opts[:channels]
name = opts[:name]
output_size = opts[:output_size]
opts =
if pool == :adaptive_lp_pool do
norm = opts[:norm]
[
name: name,
output_size: output_size,
norm: norm,
channels: channels,
op_name: pool
]
else
[
name: name,
output_size: output_size,
channels: channels,
op_name: pool
]
end
layer(pool, [x], opts)
end
## Global Pooling
@global_pooling_layers [
{:global_avg_pool, "Global average pool"},
{:global_max_pool, "Global max pool"},
{:global_lp_pool, "Global LP pool"}
]
for {pool, name} <- @global_pooling_layers do
@doc """
Adds a #{name} layer to the network.
See `Axon.Layers.#{Atom.to_string(pool)}/2` for more details.
Typically used to connect feature extractors such as those in convolutional
neural networks to fully-connected models by reducing inputs along spatial
dimensions to only feature and batch dimensions.
## Options
* `:name` - layer name.
* `:keep_axes` - option to keep reduced axes. If `true`, keeps reduced axes
with a dimension size of 1.
* `:channels` - channel configuration. One of `:first` or `:last`.
Defaults to `:last`.
"""
@doc type: :pooling
def unquote(pool)(%Axon{} = x, opts \\ []) do
global_pool(x, unquote(pool), opts)
end
end
defp global_pool(%Axon{} = x, pool, opts) do
opts = Keyword.validate!(opts, [:name, keep_axes: false, channels: :last, norm: 2])
keep_axes = opts[:keep_axes]
name = opts[:name]
channels = opts[:channels]
opts =
if pool == :global_lp_pool do
norm = opts[:norm]
[
name: name,
channels: channels,
keep_axes: keep_axes,
norm: norm,
op_name: pool
]
else
[name: name, channels: channels, keep_axes: keep_axes, op_name: pool]
end
layer(pool, [x], opts)
end
## Normalization
@normalization_with_stats_layers [
{:batch_norm, "Batch normalization", "a"},
{:instance_norm, "Instance normalization", "an"}
]
for {norm, name, a_or_an} <- @normalization_with_stats_layers do
@doc """
Adds #{a_or_an} #{name} layer to the network.
See `Axon.Layers.#{Atom.to_string(norm)}/6` for more details.
## Options
* `:name` - layer name.
* `:gamma_initializer` - gamma parameter initializer. Defaults
to `:glorot_uniform`.
* `:beta_initializer` - beta parameter initializer. Defaults to
`:zeros`.
* `:channel_index` - input feature index used for calculating
mean and variance. Defaults to `-1`.
* `:epsilon` - numerical stability term.
"""
@doc type: :normalization
def unquote(norm)(%Axon{} = x, opts \\ []) do
norm_with_stats(x, unquote(norm), opts)
end
end
defp norm_with_stats(%Axon{} = x, norm, opts) do
opts =
Keyword.validate!(opts, [
:name,
gamma_initializer: :glorot_uniform,
beta_initializer: :zeros,
channel_index: -1,
epsilon: 1.0e-5,
momentum: 0.1
])
channel_index = opts[:channel_index]
gamma_shape = &Axon.Shape.norm_param(&1, channel_index)
beta_shape = &Axon.Shape.norm_param(&1, channel_index)
mean_shape = &Axon.Shape.norm_param(&1, channel_index)
var_shape = &Axon.Shape.norm_param(&1, channel_index)
gamma = param("gamma", gamma_shape, initializer: opts[:gamma_initializer])
beta = param("beta", beta_shape, initializer: opts[:beta_initializer])
mean = param("mean", mean_shape, initializer: :zeros)
var = param("var", var_shape, initializer: :ones)
layer(
norm,
[x, gamma, beta, mean, var],
name: opts[:name],
epsilon: opts[:epsilon],
channel_index: channel_index,
momentum: opts[:momentum],
op_name: norm
)
end
@normalization_layers [
{:layer_norm, "Layer normalization", "a"}
]
for {norm, name, a_or_an} <- @normalization_layers do
@doc """
Adds #{a_or_an} #{name} layer to the network.
See `Axon.Layers.#{Atom.to_string(norm)}/4` for more details.
## Options
* `:name` - layer name.
* `:gamma_initializer` - gamma parameter initializer. Defaults
to `:glorot_uniform`.
* `:beta_initializer` - beta parameter initializer. Defaults to
`:zeros`.
* `:channel_index` - input feature index used for calculating
mean and variance. Defaults to `-1`.
* `:epsilon` - numerical stability term.
"""
@doc type: :normalization
def unquote(norm)(%Axon{} = x, opts \\ []) do
norm(x, unquote(norm), opts)
end
end
defp norm(%Axon{} = x, norm, opts) do
opts =
Keyword.validate!(opts, [
:name,
gamma_initializer: :glorot_uniform,
beta_initializer: :zeros,
channel_index: -1,
epsilon: 1.0e-5
])
channel_index = opts[:channel_index]
gamma_shape = &Axon.Shape.norm_param(&1, channel_index)
beta_shape = &Axon.Shape.norm_param(&1, channel_index)
gamma = param("gamma", gamma_shape, initializer: opts[:gamma_initializer])
beta = param("beta", beta_shape, initializer: opts[:beta_initializer])
layer(norm, [x, gamma, beta],
name: opts[:name],
epsilon: opts[:epsilon],
channel_index: channel_index,
op_name: norm
)
end
@doc """
Adds a group normalization layer to the network.
See `Axon.Layers.group_norm/4` for more details.
## Options
* `:name` - layer name.
* `:gamma_initializer` - gamma parameter initializer. Defaults
to `:glorot_uniform`.
* `:beta_initializer` - beta parameter initializer. Defaults to
`:zeros`.
* `:channel_index` - input feature index used for calculating
mean and variance. Defaults to `-1`.
* `:epsilon` - numerical stability term.
"""
@doc type: :normalization
def group_norm(%Axon{} = x, num_groups, opts \\ [])
when is_integer(num_groups) and num_groups >= 1 do
opts =
Keyword.validate!(opts, [
:name,
gamma_initializer: :ones,
beta_initializer: :zeros,
channel_index: -1,
epsilon: 1.0e-5
])
channel_index = opts[:channel_index]
gamma_shape = &Axon.Shape.norm_param(&1, channel_index)
beta_shape = &Axon.Shape.norm_param(&1, channel_index)
gamma = param("gamma", gamma_shape, initializer: opts[:gamma_initializer])
beta = param("beta", beta_shape, initializer: opts[:beta_initializer])
layer(:group_norm, [x, gamma, beta],
name: opts[:name],
epsilon: opts[:epsilon],
channel_index: channel_index,
num_groups: num_groups,
op_name: :group_norm
)
end
@doc """
Applies the given `Nx` expression to the input.
Nx layers are meant for quick applications of functions without
trainable parameters. For example, they are useful for applying
functions which apply accessors to containers:
model = Axon.container({foo, bar})
Axon.nx(model, &elem(&1, 0))
## Options
* `:name` - layer name.
"""
def nx(input, fun, opts \\ [])
@doc type: :special
def nx(%Axon{} = x, fun, opts) when is_function(fun, 1) do
opts = Keyword.validate!(opts, [:name, :op_name])
op_name = opts[:op_name] || :nx
fun_with_params = fn x, _opts -> fun.(x) end
layer(fun_with_params, [x], name: opts[:name], op_name: op_name)
end
@doc """
Adds a flatten layer to the network.
This layer will flatten all but the batch dimensions
of the input into a single layer. Typically called to flatten
the output of a convolution for use with a dense layer.
## Options
* `:name` - layer name.
"""
@doc type: :shape
def flatten(%Axon{} = x, opts \\ []) do
opts = Keyword.validate!(opts, [:name])
layer(:flatten, [x],
name: opts[:name],
op_name: :flatten
)
end
@doc """
Adds a reshape layer to the network.
This layer implements a special case of `Nx.reshape` which accounts
for possible batch dimensions in the input tensor. You may pass the
magic dimension `:batch` as a placeholder for dynamic batch sizes.
You can use `:batch` seamlessly with `:auto` dimension sizes.
If the input is an Axon constant, the reshape behavior matches that of
`Nx.reshape/2`.
## Options
* `:name` - layer name.
"""
@doc type: :shape
def reshape(%Axon{} = x, new_shape, opts \\ []) do
opts = Keyword.validate!(opts, [:name])
layer(:reshape, [x],
name: opts[:name],
shape: new_shape,
op_name: :reshape
)
end
@doc """
Adds a transpose layer to the network.
## Options
* `:name` - layer name.
"""
@doc type: :shape
def transpose(%Axon{} = x, permutation \\ nil, opts \\ []) do
opts = Keyword.validate!(opts, [:name])
layer(:transpose, [x],
name: opts[:name],
axes: permutation,
op_name: :transpose
)
end
@doc """
Adds a pad layer to the network.
This layer will pad the spatial dimensions of the input.
Padding configuration is a list of tuples for each spatial
dimension.
## Options
* `:name` - layer name.
* `:channels` - channel configuration. One of `:first` or
`:last`. Defaults to `:last`.
"""
@doc type: :shape
def pad(%Axon{} = x, config, value \\ 0.0, opts \\ [])
when is_list(config) and is_number(value) do
opts = Keyword.validate!(opts, [:name, channels: :last])
channels = opts[:channels]
layer(:pad, [x],
name: opts[:name],
padding_config: config,
value: value,
channels: channels,
op_name: :pad
)
end
@doc """
Adds a resize layer to the network.
Resizing can be used for interpolation or upsampling input
values in a neural network. For example, you can use this
layer as an upsampling layer within a GAN.
Resize shape must be a tuple representing the resized spatial
dimensions of the input tensor.
Compiles to `Axon.Layers.resize/2`.
## Options
* `:name` - layer name.
* `:method` - resize method. Defaults to `:nearest`.
* `:channels` - channel configuration. One of `:first` or
`:last`. Defaults to `:last`.
"""
@doc type: :shape
def resize(%Axon{} = x, resize_shape, opts \\ []) do
opts = Keyword.validate!(opts, [:name, method: :nearest, channels: :last])
channels = opts[:channels]
layer(:resize, [x],
name: opts[:name],
method: opts[:method],
channels: channels,
size: resize_shape,
op_name: :resize
)
end
@doc """
Adds a concatenate layer to the network.
This layer will concatenate inputs along the last
dimension unless specified otherwise.
## Options
* `:name` - layer name.
* `:axis` - concatenate axis. Defaults to `-1`.
"""
@doc type: :combinator
def concatenate(%Axon{} = x, %Axon{} = y, opts)
when is_list(opts) do
opts = Keyword.validate!(opts, [:name, axis: -1])
axis = opts[:axis]
layer(:concatenate, [container({x, y})],
name: opts[:name],
axis: axis,
op_name: :concatenate
)
end
@doc type: :combinator
def concatenate([%Axon{} | _] = inputs, opts)
when is_list(inputs) and is_list(opts) do
opts = Keyword.validate!(opts, [:name, axis: -1])
axis = opts[:axis]
layer(:concatenate, [container(List.to_tuple(inputs))],
name: opts[:name],
axis: axis,
op_name: :concatenate
)
end
@doc false
def concatenate(%Axon{} = x, %Axon{} = y), do: concatenate(x, y, [])
@doc false
def concatenate(inputs) when is_list(inputs), do: concatenate(inputs, [])
@element_wise_layers [:add, :subtract, :multiply]
for op <- @element_wise_layers do
@doc """
Adds a #{op} layer to the network.
This layer performs an element-wise #{Atom.to_string(op)} operation
on input layers. All input layers must be capable of being
broadcast together.
If one shape has a static batch size, all other shapes must have a
static batch size as well.
## Options
* `:name` - layer name.
"""
@doc type: :combinator
def unquote(op)(%Axon{} = x, %Axon{} = y, opts) do
opts = Keyword.validate!(opts, [:name])
layer(unquote(op), [container({x, y})],
name: opts[:name],
op_name: unquote(op)
)
end
@doc """
Adds a #{op} layer to the network.
This layer performs an element-wise #{Atom.to_string(op)} operation
on all input layers. All input layers must be capable of being
broadcast together.
## Options
* `:name` - layer name.
"""
@doc type: :combinator
def unquote(op)(inputs, opts) when is_list(inputs) and is_list(opts) do
opts = Keyword.validate!(opts, [:name])
layer(unquote(op), [container(List.to_tuple(inputs))],
name: opts[:name],
op_name: unquote(op)
)
end
@doc false
def unquote(op)(%Axon{} = x, %Axon{} = y) do
unquote(op)(x, y, [])
end
@doc false
def unquote(op)([%Axon{} | _] = inputs), do: unquote(op)(inputs, [])
end
@doc """
Adds a conditional layer which conditionally executes
`true_graph` or `false_graph` based on the condition `cond_fn`
at runtime.
`cond_fn` is an arity-1 function executed on the output of the
parent graph. It must return a boolean scalar tensor (e.g. 1 or 0).
The shapes of `true_graph` and `false_graph` must be equal.
"""
@doc type: :combinator
def cond(
%Axon{} = parent,
cond_fn,
%Axon{} = true_graph,
%Axon{} = false_graph,
opts \\ []
)
when is_function(cond_fn, 1) do
opts = Keyword.validate!(opts, [:name])
layer(:cond, [parent, true_graph, false_graph],
name: opts[:name],
cond: cond_fn,
op_name: :cond
)
end
@doc """
Splits input graph into a container of `n` input graphs
along the given axis.
## Options
* `:name` - layer name.
* `:axis` - concatenate axis. Defaults to `-1`.
"""
@doc type: :combinator
def split(parent, splits, opts \\ [])
def split(%Axon{} = parent, splits, opts) when is_list(splits) do
opts = Keyword.validate!(opts, [:name, axis: -1])
axis = opts[:axis]
{_, split_layers} =
for {split, i} <- Enum.with_index(splits), reduce: {0, []} do
{num_split, split_layers} ->
name =
case opts[:name] do
names when is_list(names) ->
Enum.at(names, i)
name ->
name
end
layer =
layer(
fn x, _ -> Nx.slice_along_axis(x, num_split, split, axis: axis) end,
[parent],
name: name,
op_name: :split
)
{num_split + split, [layer | split_layers]}
end
split_layers |> Enum.reverse() |> List.to_tuple()
end
def split(%Axon{} = parent, n, opts) when is_integer(n) do
opts = Keyword.validate!(opts, [:name, axis: -1])
axis = opts[:axis]
splits =
for i <- 0..(n - 1) do
name =
case opts[:name] do
names when is_list(names) ->
Enum.at(names, i)
name ->
name
end
layer(
&Axon.Layers.split/2,
[parent],
name: name,
index: i,
splits: n,
axis: axis,
op_name: :split
)
end
List.to_tuple(splits)
end
@doc """
Applies the given forward function bidirectionally and merges
the results with the given merge function.
This is most commonly used with RNNs to capture the dependencies
of a sequence in both directions.
## Options
* `axis` - Axis to reverse.
"""
def bidirectional(%Axon{} = input, forward_fun, merge_fun, opts \\ [])
when is_function(forward_fun, 1) and is_function(merge_fun, 2) do
opts = Keyword.validate!(opts, axis: 1)
forward_out = forward_fun.(input)
backward_out =
input
|> Axon.nx(&Nx.reverse(&1, axes: [opts[:axis]]))
|> forward_fun.()
|> deep_new(&Axon.nx(&1, fn x -> Nx.reverse(x, axes: [opts[:axis]]) end))
deep_merge(forward_out, backward_out, merge_fun)
end
@doc """
See `lstm/3`.
"""
@doc type: :recurrent
def lstm(%Axon{} = x, units) when is_integer(units) and units > 0 do
lstm(x, units, [])
end
@doc """
Adds a long short-term memory (LSTM) layer to the network
with a random initial hidden state.
See `lstm/4` for more details.
## Additional options
* `:recurrent_initializer` - initializer for hidden state.
Defaults to `:orthogonal`.
"""
@doc type: :recurrent
def lstm(%Axon{} = x, units, opts)
when is_integer(units) and units > 0 and is_list(opts) do
{recurrent_initializer, opts} = Keyword.pop(opts, :recurrent_initializer, :glorot_uniform)
{seed, opts} = Keyword.pop_lazy(opts, :seed, fn -> :erlang.system_time() end)
c = rnn_state(x, units, :lstm, opts[:name], "c", recurrent_initializer, seed)
h = rnn_state(x, units, :lstm, opts[:name], "h", recurrent_initializer, seed)
lstm(x, {c, h}, units, opts)
end
def lstm(%Axon{} = x, {%Axon{}, %Axon{}} = hidden_state, units)
when is_integer(units) and units > 0 do
lstm(x, hidden_state, units, [])
end
@doc """
Adds a long short-term memory (LSTM) layer to the network
with the given initial hidden state.
LSTMs apply `Axon.Layers.lstm_cell/7` over an entire input
sequence and return:
{output_sequence, {new_cell, new_hidden}}
You can use the output state as the hidden state of another
LSTM layer.
## Options
* `:name` - layer name.
* `:activation` - recurrent activation. Defaults to `:tanh`.
* `:gate` - recurrent gate function. Defaults to `:sigmoid`.
* `:unroll` - `:dynamic` (loop preserving) or `:static` (compiled)
unrolling of RNN.
* `:kernel_initializer` - initializer for kernel weights. Defaults
to `:glorot_uniform`.
* `:bias_initializer` - initializer for bias weights. Defaults to
`:zeros`.
* `:use_bias` - whether the layer should add bias to the output.
Defaults to `true`.
"""
@doc type: :recurrent
def lstm(
%Axon{} = x,
{%Axon{}, %Axon{}} = hidden_state,
units,
opts \\ []
)
when is_integer(units) and units > 0 and is_list(opts) do
opts =
Keyword.validate!(opts, [
:name,
activation: :tanh,
gate: :sigmoid,
unroll: :dynamic,
use_bias: true,
kernel_initializer: :glorot_uniform,
bias_initializer: :zeros
])
activation = opts[:activation]
gate = opts[:gate]
unroll = opts[:unroll]
input_kernel_shape = fn inp, _ -> Axon.Shape.rnn_input_kernel(inp, units, :lstm) end
hidden_kernel_shape = fn inp, _ -> Axon.Shape.rnn_hidden_kernel(inp, units, :lstm) end
bias_shape = fn inp, _ -> Axon.Shape.rnn_bias(inp, units, :lstm) end
kernel_initializer = opts[:kernel_initializer]
# Parameters
input_kernel =
param("input_kernel", {:tuple, List.duplicate(input_kernel_shape, 4)},
initializer: kernel_initializer
)
hidden_kernel =
param("hidden_kernel", {:tuple, List.duplicate(hidden_kernel_shape, 4)},
initializer: kernel_initializer
)
hidden_state_name =
case opts[:name] do
nil ->
fn _, op_counts ->
"lstm_#{op_counts[:lstm]}_hidden_state"
end
name when is_binary(name) ->
"#{name}_hidden_state"
end
hidden_state = Axon.container(hidden_state, name: hidden_state_name)
{inputs, op} =
if opts[:use_bias] do
bias_initializer = opts[:bias_initializer]
bias =
param("bias", {:tuple, List.duplicate(bias_shape, 4)}, initializer: bias_initializer)
{[x, hidden_state, input_kernel, hidden_kernel, bias], :lstm}
else
{[x, hidden_state, input_kernel, hidden_kernel], &Axon.Layers.lstm/5}
end
output =
layer(
op,
inputs,
name: opts[:name],
activation: activation,
gate: gate,
unroll: unroll,
op_name: :lstm
)
new_c_name =
case opts[:name] do
nil ->
fn _, op_counts ->
"lstm_#{op_counts[:lstm]}_c_hidden_state"
end
name when is_binary(name) ->
"#{name}_c_hidden_state"
end
new_h_name =
case opts[:name] do
nil ->
fn _, op_counts ->
"lstm_#{op_counts[:lstm]}_h_hidden_state"
end
name when is_binary(name) ->
"#{name}_h_hidden_state"
end
output_sequence_name =
case opts[:name] do
nil ->
fn _, op_counts ->
"lstm_#{op_counts[:lstm]}_output_sequence"
end
name when is_binary(name) ->
"#{name}_output_sequence"
end
output_sequence =
layer(fn x, _ -> elem(x, 0) end, [output],
name: output_sequence_name,
op_name: :elem
)
new_c =
layer(fn x, _ -> elem(elem(x, 1), 0) end, [output],
name: new_c_name,
op_name: :elem
)
new_h =
layer(fn x, _ -> elem(elem(x, 1), 1) end, [output],
name: new_h_name,
op_name: :elem
)
{output_sequence, {new_c, new_h}}
end
@doc """
See `gru/3`.
"""
@doc type: :recurrent
def gru(%Axon{} = x, units) do
gru(x, units, [])
end
@doc """
Adds a gated recurrent unit (GRU) layer to the network with
a random initial hidden state.
See `gru/4` for more details.
## Additional options
* `:recurrent_initializer` - initializer for hidden state.
Defaults to `:orthogonal`.
"""
@doc type: :recurrent
def gru(%Axon{} = x, units, opts)
when is_integer(units) and units > 0
when is_list(opts) do
{recurrent_initializer, opts} = Keyword.pop(opts, :recurrent_initializer, :glorot_uniform)
{seed, opts} = Keyword.pop_lazy(opts, :seed, fn -> :erlang.system_time() end)
h = rnn_state(x, units, :gru, opts[:name], "h", recurrent_initializer, seed)
gru(x, {h}, units, opts)
end
def gru(%Axon{} = x, {%Axon{}} = hidden_state, units) when is_integer(units) and units > 0 do
gru(x, hidden_state, units, [])
end
@doc """
Adds a gated recurrent unit (GRU) layer to the network with
the given initial hidden state.
GRUs apply `Axon.Layers.gru_cell/7` over an entire input
sequence and return:
{{new_hidden}, output_sequence}
You can use the output state as the hidden state of another
GRU layer.
## Options
* `:name` - layer name.
* `:activation` - recurrent activation. Defaults to `:tanh`.
* `:gate` - recurrent gate function. Defaults to `:sigmoid`.
* `:unroll` - `:dynamic` (loop preserving) or `:static` (compiled)
unrolling of RNN.
* `:kernel_initializer` - initializer for kernel weights. Defaults
to `:glorot_uniform`.
* `:bias_initializer` - initializer for bias weights. Defaults to
`:zeros`.
* `:use_bias` - whether the layer should add bias to the output.
Defaults to `true`.
"""
@doc type: :recurrent
def gru(
%Axon{} = x,
{%Axon{}} = hidden_state,
units,
opts
)
when is_integer(units) and units > 0 and is_list(opts) do
opts =
Keyword.validate!(opts, [
:name,
activation: :tanh,
gate: :sigmoid,
unroll: :dynamic,
use_bias: true,
kernel_initializer: :glorot_uniform,
bias_initializer: :zeros
])
activation = opts[:activation]
gate = opts[:gate]
unroll = opts[:unroll]
input_kernel_shape = fn inp, _ -> Axon.Shape.rnn_input_kernel(inp, units, :gru) end
hidden_kernel_shape = fn inp, _ -> Axon.Shape.rnn_hidden_kernel(inp, units, :gru) end
bias_shape = fn inp, _ -> Axon.Shape.rnn_bias(inp, units, :gru) end
kernel_initializer = opts[:kernel_initializer]
input_kernel =
param("input_kernel", {:tuple, List.duplicate(input_kernel_shape, 3)},
initializer: kernel_initializer
)
hidden_kernel =
param("hidden_kernel", {:tuple, List.duplicate(hidden_kernel_shape, 3)},
initializer: kernel_initializer
)
hidden_state_name =
case opts[:name] do
nil ->
fn _, op_counts ->
"gru_#{op_counts[:gru]}_hidden_state"
end
name when is_binary(name) ->
"#{name}_hidden_state"
end
hidden_state = Axon.container(hidden_state, name: hidden_state_name)
inputs =
if opts[:use_bias] do
bias_initializer = opts[:bias_initializer]
bias =
param("bias", {:tuple, List.duplicate(bias_shape, 4)}, initializer: bias_initializer)
[x, hidden_state, input_kernel, hidden_kernel, bias]
else
[x, hidden_state, input_kernel, hidden_kernel]
end
output =
layer(
:gru,
inputs,
name: opts[:name],
activation: activation,
gate: gate,
unroll: unroll,
op_name: :gru
)
new_h_name =
case opts[:name] do
nil ->
fn _, op_counts ->
"gru_#{op_counts[:gru]}_hidden_state"
end
name when is_binary(name) ->
"#{name}_hidden_state"
end
output_sequence_name =
case opts[:name] do
nil ->
fn _, op_counts ->
"gru_#{op_counts[:gru]}_output_sequence"
end
name when is_binary(name) ->
"#{name}_output_sequence"
end
output_sequence =
layer(fn x, _ -> elem(x, 0) end, [output],
name: output_sequence_name,
op_name: :elem
)
new_h =
layer(fn x, _ -> elem(elem(x, 1), 0) end, [output],
name: new_h_name,
op_name: :elem
)
{output_sequence, {new_h}}
end
@doc """
See `conv_lstm/3`.
"""
@doc type: :recurrent
def conv_lstm(%Axon{} = x, units) when is_integer(units) and units > 0 do
conv_lstm(x, units, [])
end
@doc """
Adds a convolutional long short-term memory (LSTM) layer to the network
with a random initial hidden state.
See `conv_lstm/4` for more details.
## Additional options
* `:recurrent_initializer` - initializer for hidden state. Defaults
to `:orthogonal`.
"""
@doc type: :recurrent
def conv_lstm(%Axon{} = x, units, opts)
when is_integer(units) and units > 0 and is_list(opts) do
{recurrent_initializer, opts} = Keyword.pop(opts, :recurrent_initializer, :glorot_uniform)
{seed, opts} = Keyword.pop_lazy(opts, :seed, fn -> :erlang.system_time() end)
c = rnn_state(x, units, :conv_lstm, opts[:name], "c", recurrent_initializer, seed)
h = rnn_state(x, units, :conv_lstm, opts[:name], "h", recurrent_initializer, seed)
conv_lstm(x, {c, h}, units, opts)
end
def conv_lstm(%Axon{} = x, {%Axon{}, %Axon{}} = hidden_state, units)
when is_integer(units) and units > 0 do
conv_lstm(x, hidden_state, units, [])
end
@doc """
Adds a convolutional long short-term memory (LSTM) layer to the network
with the given initial hidden state..
ConvLSTMs apply `Axon.Layers.conv_lstm_cell/5` over an entire input
sequence and return:
{{new_cell, new_hidden}, output_sequence}
You can use the output state as the hidden state of another
ConvLSTM layer.
## Options
* `:name` - layer name.
* `:padding` - convolutional padding. Defaults to `:same`.
* `:kernel_size` - convolutional kernel size. Defaults to `1`.
* `:strides` - convolutional strides. Defaults to `1`.
* `:unroll` - `:dynamic` (loop preserving) or `:static` (compiled)
unrolling of RNN.
* `:kernel_initializer` - initializer for kernel weights. Defaults
to `:glorot_uniform`.
* `:bias_initializer` - initializer for bias weights. Defaults to
`:zeros`.
* `:use_bias` - whether the layer should add bias to the output.
Defaults to `true`.
"""
@doc type: :recurrent
def conv_lstm(
%Axon{} = x,
{%Axon{}, %Axon{}} = hidden_state,
units,
opts
)
when is_integer(units) and units > 0 and is_list(opts) do
opts =
Keyword.validate!(opts, [
:name,
padding: :same,
kernel_size: 1,
strides: 1,
unroll: :dynamic,
kernel_initializer: :glorot_uniform,
bias_initializer: :zeros,
use_bias: true
])
padding = opts[:padding]
kernel_size = opts[:kernel_size]
strides = opts[:strides]
unroll = opts[:unroll]
kernel_initializer = opts[:kernel_initializer]
hidden_kernel_shape = fn _, {inp, _} ->
shape = Tuple.delete_at(inp, 1)
Axon.Shape.conv_kernel(shape, 4 * units, kernel_size, :first, 1)
end
input_kernel_shape = fn inp, _ ->
shape = Tuple.delete_at(inp, 1)
Axon.Shape.conv_kernel(shape, 4 * units, kernel_size, :first, 1)
end
bias_shape = fn inp, _ ->
shape = Tuple.delete_at(inp, 1)
Axon.Shape.conv_bias(shape, 4 * units, kernel_size, :first, 1)
end
wi = param("input_kernel", {:tuple, [input_kernel_shape]}, initializer: kernel_initializer)
wh = param("hidden_kernel", {:tuple, [hidden_kernel_shape]}, initializer: kernel_initializer)
hidden_state_name =
case opts[:name] do
nil ->
fn _, op_counts ->
"conv_lstm_#{op_counts[:conv_lstm]}_hidden_state"
end
name when is_binary(name) ->
"#{name}_hidden_state"
end
hidden_state = Axon.container(hidden_state, name: hidden_state_name)
{inputs, op} =
if opts[:use_bias] do
bias_initializer = opts[:bias_initializer]
b = param("bias", {:tuple, [bias_shape]}, initializer: bias_initializer)
{[x, hidden_state, wi, wh, b], :conv_lstm}
else
{[x, hidden_state, wi, wh], :conv_lstm}
end
output =
layer(
op,
inputs,
name: opts[:name],
conv_opts: [
strides: strides,
padding: padding
],
unroll: unroll,
op_name: :conv_lstm
)
new_c_name =
case opts[:name] do
nil ->
fn _, op_counts ->
"conv_lstm_#{op_counts[:lstm]}_c_hidden_state"
end
name when is_binary(name) ->
"#{name}_c_hidden_state"
end
new_h_name =
case opts[:name] do
nil ->
fn _, op_counts ->
"conv_lstm_#{op_counts[:lstm]}_h_hidden_state"
end
name when is_binary(name) ->
"#{name}_h_hidden_state"
end
output_sequence_name =
case opts[:name] do
nil ->
fn _, op_counts ->
"conv_lstm_#{op_counts[:lstm]}_output_sequence"
end
name when is_binary(name) ->
"#{name}_output_sequence"
end
output_sequence =
layer(fn x, _ -> elem(x, 0) end, [output],
name: output_sequence_name,
op_name: :elem
)
new_c =
layer(fn x, _ -> elem(elem(x, 1), 0) end, [output],
name: new_c_name,
op_name: :elem
)
new_h =
layer(fn x, _ -> elem(elem(x, 1), 1) end, [output],
name: new_h_name,
op_name: :elem
)
{output_sequence, {new_c, new_h}}
end
defp rnn_state(x, units, rnn_type, parent_name, state_name, initializer, seed) do
initializer = initializer || :glorot_uniform
key_state =
param("key", fn _ -> {2} end,
type: {:u, 32},
initializer: fn _, _ -> Nx.Random.key(seed) end
)
name =
case parent_name do
nil ->
fn _, op_counts ->
"lstm_#{op_counts[rnn_type]}_#{state_name}_hidden_state"
end
parent_name when is_binary(parent_name) ->
"#{parent_name}_#{state_name}_hidden_state"
end
fun = fn inputs, key, _opts ->
shape = Axon.Shape.rnn_hidden_state(Nx.shape(inputs), units, rnn_type)
case initializer do
fun when is_function(fun) ->
fun.(shape)
fun when is_atom(fun) ->
fun = apply(Axon.Initializers, fun, [])
{:arity, arity} = Function.info(fun, :arity)
cond do
arity == 2 ->
fun.(shape, {:f, 32})
arity == 3 ->
fun.(shape, {:f, 32}, key)
true ->
raise ArgumentError, "bad arity for initializer"
end
end
end
layer(fun, [x, key_state], name: name, op_name: :recurrent_state)
end
@doc """
Adds an embedding layer to the network.
An embedding layer initializes a kernel of shape `{vocab_size, embedding_size}`
which acts as a lookup table for sequences of discrete tokens (e.g. sentences).
Embeddings are typically used to obtain a dense representation of a sparse input
space.
## Options
* `:name` - layer name.
* `:kernel_initializer` - initializer for `kernel` weights. Defaults
to `:uniform`.
"""
@doc type: :linear
def embedding(%Axon{} = x, vocab_size, embedding_size, opts \\ []) do
opts = Keyword.validate!(opts, [:name, kernel_initializer: :uniform])
kernel_shape = &Axon.Shape.embedding_kernel(&1, vocab_size, embedding_size)
kernel = param("kernel", kernel_shape, initializer: opts[:kernel_initializer])
layer(:embedding, [x, kernel], name: opts[:name], op_name: :embedding)
end
@doc """
Adds a bias layer to the network.
A bias layer simply adds a trainable bias to an input.
## Options
* `:name` - layer name.
* `:bias_initializer` - initializer for `bias` weights. Defaults
to `:zeros`.
"""
@doc type: :linear
def bias(%Axon{} = x, opts \\ []) do
opts = Keyword.validate!(opts, [:name, bias_initializer: :zeros])
bias_shape = fn shape -> {elem(shape, tuple_size(shape) - 1)} end
bias = param("bias", bias_shape, initializer: opts[:bias_initializer])
layer(:bias, [x, bias], name: opts[:name], op_name: :bias)
end
@doc """
Adds a stack columns layer to the network.
A stack columns layer is designed to be used with `Nx.LazyContainer`
data structures like Explorer DataFrames. Given an input which is a
DataFrame, `stack_columns/2` will stack the columns in each row to
create a single vector.
You may optionally specify `:ignore` to ignore certain columns in
the container.
## Options
* `:name` - layer name.
* `:ignore` - keys to ignore when stacking.
"""
@doc type: :special
def stack_columns(%Axon{} = x, opts \\ []) do
opts = Keyword.validate!(opts, [:name, ignore: []])
layer(:stack_columns, [x], name: opts[:name], ignore: opts[:ignore], op_name: :stack_columns)
end
@doc """
Freezes parameters returned from the given function or predicate.
`fun` can be a predicate `:all`, `up: n`, or `down: n`. `:all`
freezes all parameters in the model, `up: n` freezes the first `n`
layers up (starting from output), and `down: n` freezes the first `n`
layers down (starting from input).
`fun` may also be a predicate function which takes a parameter and
returns `true` if a parameter should be frozen or `false` otherwise.
Freezing parameters is useful when performing transfer learning
to leverage features learned from another problem in a new problem.
For example, it's common to combine the convolutional base from
larger models trained on ImageNet with fresh fully-connected classifiers.
The combined model is then trained on fresh data, with the convolutional
base frozen so as not to lose information. You can see this example
in code here:
cnn_base = get_pretrained_cnn_base()
model =
cnn_base
|> Axon.freeze()
|> Axon.flatten()
|> Axon.dense(1024, activation: :relu)
|> Axon.dropout()
|> Axon.dense(1000, activation: :softmax)
model
|> Axon.Loop.trainer(:categorical_cross_entropy, Axon.Optimizers.adam(0.005))
|> Axon.Loop.run(data, epochs: 10)
When compiled, frozen parameters are wrapped in `Nx.Defn.Kernel.stop_grad/1`,
which zeros out the gradient with respect to the frozen parameter. Gradients
of frozen parameters will return `0.0`, meaning they won't be changed during
the update process.
"""
@doc type: :model
def freeze(model, fun_or_predicate \\ :all) do
freeze(model, fun_or_predicate, true)
end
defp freeze(%Axon{output: id, nodes: nodes} = axon, fun_or_predicate, flag) do
{nodes, _} = traverse_nodes(id, nodes, [], MapSet.new())
nodes =
case fun_or_predicate do
:all ->
freeze_nodes(nodes, flag)
[{:up, n}] ->
{pre, post} = Enum.split(nodes, n)
freeze_nodes(pre, flag) ++ post
[{:down, n}] ->
{pre, post} = Enum.split(nodes, -n)
pre ++ freeze_nodes(post, flag)
fun ->
Enum.map(nodes, fn %Axon.Node{parameters: params} = axon_node ->
%{
axon_node
| parameters:
Enum.map(params, fn p ->
if fun.(p), do: %{p | frozen: flag}, else: p
end)
}
end)
end
%{axon | nodes: Map.new(nodes, fn %{id: id} = node -> {id, node} end)}
end
defp freeze_nodes(nodes, flag) do
Enum.map(nodes, fn %Axon.Node{parameters: params} = axon_node ->
%{axon_node | parameters: Enum.map(params, fn p -> %{p | frozen: flag} end)}
end)
end
@doc """
Unfreezes parameters returned from the given function or predicate.
`fun` can be a predicate `:all`, `up: n`, or `down: n`. `:all`
freezes all parameters in the model, `up: n` unfreezes the first `n`
layers up (starting from output), and `down: n` freezes the first `n`
layers down (starting from input).
`fun` may also be a predicate function which takes a parameter and
returns `true` if a parameter should be unfrozen or `false` otherwise.
Unfreezing parameters is useful when fine tuning a model which you
have previously frozen and performed transfer learning on. You may
want to unfreeze some of the later frozen layers in a model and
fine tune them specifically for your application:
cnn_base = get_pretrained_cnn_base()
model =
frozen_model
|> Axon.unfreeze(up: 25)
model
|> Axon.Loop.trainer(:categorical_cross_entropy, Axon.Optimizers.adam(0.0005))
|> Axon.Loop.run(data, epochs: 10)
When compiled, frozen parameters are wrapped in `Nx.Defn.Kernel.stop_grad/1`,
which zeros out the gradient with respect to the frozen parameter. Gradients
of frozen parameters will return `0.0`, meaning they won't be changed during
the update process.
"""
@doc type: :model
def unfreeze(model, fun_or_predicate \\ :all) do
freeze(model, fun_or_predicate, false)
end
@doc """
Attaches a hook to the given Axon model.
Hooks compile down to `Nx.Defn.Kernel.hook/3` and provide the same
functionality for adding side-effecting operations to a compiled
model. For example, you can use hooks to inspect intermediate activations,
send data to an external service, and more.
Hooks can be configured to be invoked on the following events:
* `:initialize` - on model initialization.
* `:pre_forward` - before layer forward pass is invoked.
* `:forward` - after layer forward pass is invoked.
* `:backward` - after layer backward pass is invoked.
To invoke a hook on every single event, you may pass `:all` to `on:`.
Axon.input("input", shape: {nil, 1}) |> Axon.attach_hook(&IO.inspect/1, on: :all)
The default event is `:forward`, assuming you want a hook invoked
on the layers forward pass.
You may configure hooks to run in one of only training or inference
mode using the `:mode` option. The default mode is `:both` to be invoked
during both train and inference mode.
Axon.input("input", shape: {nil, 1}) |> Axon.attach_hook(&IO.inspect/1, on: :forward, mode: :train)
You can also attach multiple hooks to a single layer. Hooks are invoked in
the order in which they are declared. If order is important, you should attach
hooks in the order you want them to be executed:
Axon.input("input", shape: {nil, 1})
# I will be executed first
|> Axon.attach_hook(&IO.inspect/1)
# I will be executed second
|> Axon.attach_hook(fn _ -> IO.write("HERE") end)
Hooks are executed at their point of attachment. You must insert hooks at each point
you want a hook to execute during model execution.
Axon.input("input", shape: {nil, 1})
|> Axon.attach_hook(&IO.inspect/1)
|> Axon.relu()
|> Axon.attach_hook(&IO.inspect/1)
"""
@doc type: :debug
def attach_hook(%Axon{output: id, nodes: nodes} = axon, fun, opts \\ []) do
opts = Keyword.validate!(opts, on: :forward, mode: :both)
on_event = opts[:on]
mode = opts[:mode]
updated_nodes =
Map.update!(nodes, id, fn axon_node ->
%{axon_node | hooks: [{on_event, mode, fun}]}
end)
%{axon | nodes: updated_nodes}
end
## Graph Manipulation and Utilities
# TODO: Revisit later with new decoupled structs
# e.g. there should be a node API and graph API
@doc """
Returns a node's immediate parameters.
Note this does not take into account parameters of
parent layers - only the parameters which belong to
the immediate layer.
"""
@doc type: :graph
def get_parameters(%Axon{output: id, nodes: nodes}) do
Access.get(nodes, [id, :parameters])
end
@doc """
Sets a node's immediate parameters to the given
parameters.
Note this does not take into account parameters of
parent layers - only the parameters which belong to
the immediate layer.
The new parameters must be compatible with the layer's
old parameters.
"""
@doc type: :graph
def set_parameters(%Axon{output: id, nodes: nodes} = axon, new_params) do
# TODO: Check compatibility
updated_nodes =
Map.update!(nodes, id, fn axon_node ->
%{axon_node | parameters: new_params}
end)
%{axon | nodes: updated_nodes}
end
@doc """
Returns a node's immediate input options.
Note that this does not take into account options of
parent layers, only the option which belong to the
immediate layer.
"""
@doc type: :graph
def get_options(%Axon{output: id, nodes: nodes}) do
Access.get(nodes, [id, :opts])
end
@doc """
Sets a node's immediate options to the given input
options.
Note that this does not take into account options of
parent layers, only the option which belong to the
immediate layer.
New options must be compatible with the given layer
op. Adding unsupported options to an Axon layer will
result in an error at graph execution time.
"""
@doc type: :graph
def set_options(%Axon{output: id, nodes: nodes} = axon, new_opts) do
updated_nodes =
Map.update!(nodes, id, fn axon_node ->
%{axon_node | opts: new_opts}
end)
%{axon | nodes: updated_nodes}
end
@doc """
Returns information about a model's inputs.
"""
@doc type: :graph
def get_inputs(%Axon{} = axon) do
reduce_nodes(axon, %{}, fn
%Axon.Node{op: :input, name: name, opts: opts}, inputs ->
name = name.(:input, %{})
Map.put(inputs, name, opts[:shape])
_, inputs ->
inputs
end)
end
@doc """
Returns a model's output shape from the given input
template.
"""
@doc type: :graph
def get_output_shape(%Axon{} = axon, inputs, opts \\ []) do
{init_fn, forward_fn} = build(axon, opts)
out =
Nx.Defn.jit(
fn inputs ->
forward_fn.(init_fn.(inputs, %{}), inputs)
end,
compiler: Axon.Defn
).(inputs)
safe_shape(out)
end
defp safe_shape(container_or_tensor) do
case container_or_tensor do
%Axon.None{} = none ->
none
%Nx.Tensor{} = tensor ->
Nx.shape(tensor)
container ->
deep_new(container, &Nx.shape/1)
end
end
@doc """
Returns a map of model op counts for each unique operation
in a model by their given `:op_name`.
## Examples
iex> model = Axon.input("input", shape: {nil, 1}) |> Axon.dense(2)
iex> Axon.get_op_counts(model)
%{input: 1, dense: 1}
iex> model = Axon.input("input", shape: {nil, 1}) |> Axon.tanh() |> Axon.tanh()
iex> Axon.get_op_counts(model)
%{input: 1, tanh: 2}
"""
@doc type: :graph
def get_op_counts(%Axon{} = axon) do
reduce_nodes(axon, %{}, fn %Axon.Node{op: op}, op_counts ->
Map.update(op_counts, op, 1, fn x -> x + 1 end)
end)
end
@doc """
Traverses graph nodes in order, applying `fun` to each
node exactly once to return a transformed node in its
place(s) in the graph.
This function maintains an internal cache which ensures
each node is only visited and transformed exactly once.
`fun` must accept an Axon node and return an Axon node.
Please note that modifying node lineage (e.g. altering
a node's parent) will result in disconnected graphs.
## Examples
One common use of this function is to implement common
instrumentation between layers without needing to build
a new explicitly instrumented version of a model. For example,
you can use this function to visualize intermediate activations
of all convolutional layers in a model:
instrumented_model = Axon. (model, fn
%Axon{op: :conv} = graph ->
Axon.attach_hook(graph, &visualize_activations/1)
graph ->
graph
end)
Another use case is to replace entire classes of layers
with another. For example, you may want to replace all
relu layers with tanh layers:
new_model = Axon.map_nodes(model, fn
%Axon{op: :relu} = graph ->
# Get nodes immediate parent
parent = Axon.get_parent(graph)
# Replace node with a tanh
Axon.tanh(parent)
graph ->
graph
end)
"""
@doc type: :graph
def map_nodes(%Axon{output: id, nodes: nodes} = axon, fun) when is_function(fun, 1) do
{inorder_nodes, _} = traverse_nodes(id, nodes, [], MapSet.new())
updated_nodes = Map.new(inorder_nodes, fn %{id: id} = axon_node -> {id, fun.(axon_node)} end)
%{axon | nodes: updated_nodes}
end
@doc """
Traverses graph nodes in order, applying `fun` to each
node exactly once to return a transformed node in its
place(s) in the graph.
This function maintains an internal cache which ensures
each node is only visited and transformed exactly once.
`fun` must accept an Axon node and accumulator and return
an updated accumulator.
## Examples
Internally this function is used in several places to accumulate
graph metadata. For example, you can use it to count the number
of a certain type of operation in the graph:
Axon.reduce_nodes(model, 0, fn
%Axon.Nodes{op: :relu}, acc -> acc + 1
_, acc -> acc
end)
"""
@doc type: :graph
def reduce_nodes(%Axon{output: id, nodes: nodes}, acc, fun) when is_function(fun, 2) do
{inorder_nodes, _} = traverse_nodes(id, nodes, [], MapSet.new())
Enum.reduce(inorder_nodes, acc, fun)
end
defp traverse_nodes(id, nodes, acc, visited) do
if MapSet.member?(visited, id) do
{acc, visited}
else
%{op: op, parent: parents} = parent = nodes[id]
{acc, visited} =
case op do
:container ->
[container] = parents
deep_reduce(container, {acc, visited}, fn pid, {acc, visited} ->
traverse_nodes(pid, nodes, acc, visited)
end)
_ ->
Enum.reduce(parents, {acc, visited}, fn pid, {acc, visited} ->
traverse_nodes(pid, nodes, acc, visited)
end)
end
{[parent | acc], MapSet.put(visited, id)}
end
end
# TODO: Do not duplicate
defp deep_reduce(item, acc, fun) when is_integer(item) do
fun.(item, acc)
end
defp deep_reduce(map, acc, fun) do
Nx.Container.reduce(map, acc, &recur_deep_reduce(&1, &2, fun))
end
defp recur_deep_reduce(value, acc, fun) do
case value do
%Axon{} = val ->
fun.(val, acc)
%Nx.Tensor{} = val ->
fun.(val, acc)
%{axon: :axon} = val ->
fun.(val, acc)
val when is_integer(val) ->
fun.(val, acc)
val ->
deep_reduce(val, acc, fun)
end
end
defp deep_map_reduce(leaf, acc, fun) when is_integer(leaf), do: fun.(leaf, acc)
defp deep_map_reduce(container, acc, fun) do
Nx.Container.traverse(container, acc, &recur_deep_map_reduce(&1, &2, fun))
end
defp recur_deep_map_reduce(leaf, acc, fun) do
case leaf do
%Axon{} = leaf ->
fun.(leaf, acc)
%Nx.Tensor{} = leaf ->
fun.(leaf, acc)
container ->
deep_map_reduce(container, acc, fun)
end
end
@doc """
Pops the top node off of the graph.
This returns the popped node and the updated graph:
{_node, model} = Axon.pop_node(model)
"""
@doc type: :graph
def pop_node(%Axon{nodes: nodes, output: id} = axon) do
{%{parent: [parent_id]} = popped, nodes} = Map.pop!(nodes, id)
{popped, %{axon | nodes: nodes, output: parent_id}}
end
@doc """
Builds the given model to `{init_fn, predict_fn}`.
The given functions can be either given as arguments to `Nx.Defn`
functions or be invoked directly, to perform just-in-time compilation
and execution. If you want to compile the model (instead of just-in-time)
based on a predefined initialization shape, see `compile/4`.
## `init_fn`
The `init_fn` receives two arguments, the input template and
an optional map with initial parameters for layers or namespaces:
{init_fn, predict_fn} = Axon.build(model)
init_fn.(Nx.template({1, 1}, {:f, 32}), %{"dense_0" => dense_params})
## `predict_fn`
The `predict_fn` receives two arguments, the trained parameters
and the actual inputs:
{_init_fn, predict_fn} = Axon.build(model, opts)
predict_fn.(params, input)
## Options
* `:mode` - one of `:inference` or `:train`. Forwarded to layers
to control differences in compilation at training or inference time.
Defaults to `:inference`
* `:debug` - if `true`, will log graph traversal and generation
metrics. Also forwarded to JIT if debug mode is available
for your chosen compiler or backend. Defaults to `false`
All other options are forwarded to the default JIT compiler
or backend.
"""
@doc type: :model
def build(model, opts \\ []) when is_list(opts) do
{init_fn, predict_fn} = Axon.Compiler.build(model, opts)
opts = [on_conflict: :reuse] ++ opts
{Nx.Defn.jit(init_fn, opts), Nx.Defn.jit(predict_fn, opts)}
end
@doc """
Compiles the given model to `{init_fn, predict_fn}`.
This function will compile a model specialized to the given
input shapes and types. This is useful for avoiding the overhead
of long compilations at program runtime. You must provide template
inputs which match the expected shapes and types of inputs at
execution time.
This function makes use of the built-in `Nx.Defn.compile/3`. Note
that passing inputs which differ in shape or type from the templates
provided to this function will result in a crash.
"""
@doc type: :model
def compile(model, template, init_params \\ %{}, opts \\ []) when is_list(opts) do
{init_fn, predict_fn} = build(model, opts)
init_params = Nx.Defn.jit_apply(init_fn, [template, init_params], opts)
predict_compiled_fn = Nx.Defn.compile(predict_fn, [init_params, template], opts)
{init_params, predict_compiled_fn}
end
@doc """
Compiles and returns the given model's init function
expression with the given options.
The returned expression is an Nx expression which can be
traversed and lowered to an IR or inspected for debugging
purposes.
You may optionally specify initial parameters for some layers or
namespaces by passing a partial parameter map:
Axon.trace_init(model, %{"dense_0" => dense_params})
The parameter map will be merged with the initialized model
parameters.
## Options
* `:debug` - if `true`, will log graph traversal and generation
metrics. Also forwarded to JIT if debug mode is available
for your chosen compiler or backend. Defaults to `false`
"""
@doc type: :debug
def trace_init(model, template, params \\ %{}, opts \\ []) do
{init_fn, _} = build(model, opts)
Nx.Defn.jit(init_fn, compiler: Axon.Defn).(template, params)
end
@doc """
Compiles and returns the given model's forward function
expression with the given options.
The returned expression is an Nx expression which can be
traversed and lowered to an IR or inspected for debugging
purposes.
## Options
* `:mode` - one of `:inference` or `:train`. Forwarded to layers
to control differences in compilation at training or inference time.
Defaults to `:inference`
* `:debug` - if `true`, will log graph traversal and generation
metrics. Also forwarded to JIT if debug mode is available
for your chosen compiler or backend. Defaults to `false`
"""
@doc type: :debug
def trace_forward(model, inputs, params, opts \\ []) when is_list(opts) do
{_, forward_fun} = build(model, opts)
Nx.Defn.jit(forward_fun, compiler: Axon.Defn).(params, inputs)
end
@doc """
Compiles and returns the given model's backward function
expression with respect to the given loss function.
The returned expression is an Nx expression which can be
traversed and lowered to an IR or inspected for debugging
purposes.
The given loss function must be a scalar loss function which
expects inputs and targets with the same shapes as the model's
output shapes as determined by the model's signature.
## Options
* `:debug` - if `true`, will log graph traversal and generation
metrics. Also forwarded to JIT if debug mode is available
for your chosen compiler or backend. Defaults to `false`
"""
@doc type: :debug
def trace_backward(model, inputs, params, loss, opts \\ []) do
{_, forward_fn} = build(model, opts)
backward_fn = fn params, inputs, targets ->
Nx.Defn.grad(params, fn params ->
%{prediction: preds} = forward_fn.(params, inputs)
loss.(targets, preds)
end)
end
outputs = Nx.Defn.jit(forward_fn, compiler: Axon.Defn).(params, inputs)
inputs = [params, inputs, outputs]
apply(Nx.Defn.jit(backward_fn, compiler: Axon.Defn), inputs)
end
@doc false
@deprecated "Use Axon.build/2 instead"
def init(model, template, params \\ %{}, opts \\ []) when is_list(opts) do
{init_fn, _predict_fn} = build(model, opts)
init_fn.(template, params)
end
@doc """
Builds and runs the given Axon `model` with `params` and `input`.
This is equivalent to calling `build/2` and then invoking the
predict function.
## Options
* `:mode` - one of `:inference` or `:train`. Forwarded to layers
to control differences in compilation at training or inference time.
Defaults to `:inference`
* `:debug` - if `true`, will log graph traversal and generation
metrics. Also forwarded to JIT if debug mode is available
for your chosen compiler or backend. Defaults to `false`
All other options are forwarded to the default JIT compiler
or backend.
"""
@doc type: :model
def predict(%Axon{} = model, params, input, opts \\ []) when is_list(opts) do
{_init_fn, predict_fn} = build(model, opts)
predict_fn.(params, input)
end
## Inspection
defimpl Inspect do
import Inspect.Algebra
def inspect(%Axon{output: id, nodes: nodes} = axon, opts) do
inputs =
axon
|> Axon.get_inputs()
|> Enum.sort()
|> Map.new()
op_counts = Axon.get_op_counts(axon)
%Axon.Node{op_name: op_name, name: name_fn} = nodes[id]
op_counts = Map.update(op_counts, op_name, 0, fn x -> x - 1 end)
output_name = name_fn.(op_name, op_counts)
node_count = Enum.count(axon.nodes)
inner =
concat([
line(),
"inputs: #{inspect(inputs)}",
line(),
"outputs: #{inspect(output_name)}",
line(),
"nodes: #{inspect(node_count)}"
])
force_unfit(
concat([
color("#Axon<", :map, opts),
nest(inner, 2),
line(),
color(">", :map, opts)
])
)
end
end
# Serialization
@doc """
Serializes a model and its parameters for persisting
models to disk or elsewhere.
Model and parameters are serialized as a tuple, where the
model is converted to a recursive map to ensure compatibility
with future Axon versions and the parameters are serialized
using `Nx.serialize/2`. There is some additional metadata included
such as current serialization version for compatibility.
Serialization `opts` are forwarded to `Nx.serialize/2` and
`:erlang.term_to_binary/2` for controlling compression options.
## Examples
iex> model = Axon.input("input", shape: {nil, 2}) |> Axon.dense(1, kernel_initializer: :zeros, activation: :relu)
iex> {init_fn, _} = Axon.build(model)
iex> params = init_fn.(Nx.template({1, 2}, :f32), %{})
iex> serialized = Axon.serialize(model, params)
iex> {saved_model, saved_params} = Axon.deserialize(serialized)
iex> {_, predict_fn} = Axon.build(saved_model)
iex> predict_fn.(saved_params, Nx.tensor([[1.0, 1.0]]))
#Nx.Tensor<
f32[1][1]
[
[0.0]
]
>
"""
@doc type: :model
def serialize(%Axon{output: id, nodes: nodes}, params, opts \\ []) do
Logger.warning(
"Attempting to serialize an Axon model. Serialization is discouraged" <>
" and will be deprecated, then removed in future releases. You should" <>
" keep your model definitions as code and serialize your parameters using" <>
" `Nx.serialize/2`."
)
nodes =
Map.new(nodes, fn {k, %{op: op, op_name: op_name} = v} ->
validate_serialized_op!(op_name, op)
node_meta = Map.from_struct(v)
{k, Map.put(node_meta, :node, :node)}
end)
model_meta = %{output: id, nodes: nodes, axon: :axon}
params = Nx.serialize(params, opts)
:erlang.term_to_binary({@file_version, model_meta, params}, opts)
end
# TODO: Raise on next release
defp validate_serialized_op!(op_name, op) when is_function(op) do
fun_info = Function.info(op)
case fun_info[:type] do
:local ->
Logger.warning(
"Attempting to serialize anonymous function in #{inspect(op_name)} layer," <>
" this will result in errors during deserialization between" <>
" different processes, and will be unsupported in a future" <>
" release. You should instead use a fully-qualified MFA function" <>
" such as &Axon.Layers.dense/3"
)
{:type, :external} ->
:ok
end
end
defp validate_serialized_op!(_name, op) when is_atom(op), do: :ok
@doc """
Deserializes serialized model and parameters into a `{model, params}`
tuple.
It is the opposite of `Axon.serialize/3`.
## Examples
iex> model = Axon.input("input", shape: {nil, 2}) |> Axon.dense(1, kernel_initializer: :zeros, activation: :relu)
iex> {init_fn, _} = Axon.build(model)
iex> params = init_fn.(Nx.template({1, 2}, :f32), %{})
iex> serialized = Axon.serialize(model, params)
iex> {saved_model, saved_params} = Axon.deserialize(serialized)
iex> {_, predict_fn} = Axon.build(saved_model)
iex> predict_fn.(saved_params, Nx.tensor([[1.0, 1.0]]))
#Nx.Tensor<
f32[1][1]
[
[0.0]
]
>
"""
@doc type: :model
def deserialize(serialized, opts \\ []) do
Logger.warning(
"Attempting to deserialize a serialized Axon model. Deserialization" <>
" is discouraged and will be deprecated, then removed in future" <>
" releases. You should keep your model definitions as code and" <>
" serialize your parameters using `Nx.serialize/2`."
)
{1, model_meta, serialized_params} = :erlang.binary_to_term(serialized, opts)
%{nodes: nodes, output: id} = model_meta
nodes =
Map.new(nodes, fn {k, %{op_name: op_name, op: op} = v} ->
validate_deserialized_op!(op_name, op)
node_struct =
v
|> Map.delete(:node)
|> then(&struct(Axon.Node, &1))
{k, node_struct}
end)
model = %Axon{output: id, nodes: nodes}
params = Nx.deserialize(serialized_params, opts)
{model, params}
end
# TODO: Raise on next release
defp validate_deserialized_op!(op_name, op) when is_function(op) do
fun_info = Function.info(op)
case fun_info[:type] do
:local ->
Logger.warning(
"Attempting to deserialize anonymous function in #{inspect(op_name)} layer," <>
" this will result in errors during deserialization between" <>
" different processes, and will be unsupported in a future" <>
" release"
)
:external ->
unless function_exported?(fun_info[:module], fun_info[:name], fun_info[:arity]) do
Logger.warning(
"Attempting to deserialize model which depends on function" <>
" #{inspect(op)} in layer #{inspect(op_name)} which does not exist in" <>
" the current environment, check your dependencies"
)
end
end
end
defp validate_deserialized_op!(op, _op_name) when is_atom(op), do: :ok
## Helpers
@valid_initializers [:zeros, :ones, :uniform, :normal, :identity] ++
[:lecun_uniform, :lecun_normal, :he_uniform, :he_normal] ++
[:glorot_uniform, :glorot_normal, :variance_scaling]
defp validate_initializer!(initializer)
when is_atom(initializer) and initializer in @valid_initializers do
apply(Axon.Initializers, initializer, [])
end
defp validate_initializer!(initializer) when is_function(initializer, 2) do
initializer
end
defp validate_initializer!(initializer) when is_function(initializer, 3) do
initializer
end
defp validate_initializer!(initializer) do
raise ArgumentError,
"initializer must be one of #{inspect(@valid_initializers)}," <>
" or an arity-3 function accepting initializer shape, type, and key" <>
" got #{inspect(initializer)}"
end
# Names are generated lazily at inspect, initialization, and compile
# time, so for name we return a function which takes `op` and `op_count`
# and returns a unique name for the given model.
defp name(type, nil) do
fn op, op_counts ->
count = op_counts[op] || 0
Atom.to_string(type) <> "_#{count}"
end
end
defp name(_type, name_fn) when is_function(name_fn, 2) do
name_fn
end
defp name(_type, name) when is_binary(name) do
fn _, _ -> name end
end
defp name(_type, name) do
raise ArgumentError,
"expected layer name to be a binary, a function or nil, " <>
"got: #{inspect(name)}"
end
end
