Table Of Contents
Table Of Contents

LayerNorm

class mxnet.gluon.nn.LayerNorm(axis=-1, epsilon=1e-05, center=True, scale=True, beta_initializer='zeros', gamma_initializer='ones', in_channels=0, prefix=None, params=None)[source]

Applies layer normalization to the n-dimensional input array. This operator takes an n-dimensional input array and normalizes the input using the given axis:

\[out = \frac{x - mean[data, axis]}{ \sqrt{Var[data, axis]} + \epsilon} * gamma + beta\]
Parameters:
  • axis (int, default -1) – The axis that should be normalized. This is typically the axis of the channels.
  • epsilon (float, default 1e-5) – Small float added to variance to avoid dividing by zero.
  • center (bool, default True) – If True, add offset of beta to normalized tensor. If False, beta is ignored.
  • scale (bool, default True) – If True, multiply by gamma. If False, gamma is not used.
  • beta_initializer (str or Initializer, default ‘zeros’) – Initializer for the beta weight.
  • gamma_initializer (str or Initializer, default ‘ones’) – Initializer for the gamma weight.
  • in_channels (int, default 0) – Number of channels (feature maps) in input data. If not specified, initialization will be deferred to the first time forward is called and in_channels will be inferred from the shape of input data.
Inputs:
  • data: input tensor with arbitrary shape.
Outputs:
  • out: output tensor with the same shape as data.

References

Layer Normalization

Examples

>>> # Input of shape (2, 5)
>>> x = mx.nd.array([[1, 2, 3, 4, 5], [1, 1, 2, 2, 2]])
>>> # Layer normalization is calculated with the above formula
>>> layer = LayerNorm()
>>> layer.initialize(ctx=mx.cpu(0))
>>> layer(x)
[[-1.41421    -0.707105    0.          0.707105    1.41421   ]
 [-1.2247195  -1.2247195   0.81647956  0.81647956  0.81647956]]
<NDArray 2x5 @cpu(0)>
__init__(axis=-1, epsilon=1e-05, center=True, scale=True, beta_initializer='zeros', gamma_initializer='ones', in_channels=0, prefix=None, params=None)[source]

Initialize self. See help(type(self)) for accurate signature.

Methods

__init__([axis, epsilon, center, scale, …]) Initialize self.
apply(fn) Applies fn recursively to every child block as well as self.
cast(dtype) Cast this Block to use another data type.
collect_params([select]) Returns a ParameterDict containing this Block and all of its children’s Parameters(default), also can returns the select ParameterDict which match some given regular expressions.
export(path[, epoch]) Export HybridBlock to json format that can be loaded by SymbolBlock.imports, mxnet.mod.Module or the C++ interface.
forward(x, *args) Defines the forward computation.
hybrid_forward(F, data, gamma, beta) Overrides to construct symbolic graph for this Block.
hybridize([active]) Activates or deactivates HybridBlock s recursively.
infer_shape(*args) Infers shape of Parameters from inputs.
infer_type(*args) Infers data type of Parameters from inputs.
initialize([init, ctx, verbose, force_reinit]) Initializes Parameter s of this Block and its children.
load_parameters(filename[, ctx, …]) Load parameters from file previously saved by save_parameters.
load_params(filename[, ctx, allow_missing, …]) [Deprecated] Please use load_parameters.
name_scope() Returns a name space object managing a child Block and parameter names.
register_child(block[, name]) Registers block as a child of self.
register_forward_hook(hook) Registers a forward hook on the block.
register_forward_pre_hook(hook) Registers a forward pre-hook on the block.
save_parameters(filename) Save parameters to file.
save_params(filename) [Deprecated] Please use save_parameters.
summary(*inputs) Print the summary of the model’s output and parameters.

Attributes

name Name of this Block, without ‘_’ in the end.
params Returns this Block’s parameter dictionary (does not include its children’s parameters).
prefix Prefix of this Block.