mxnet.gluon.nn.activations

Basic neural network layers.

Classes

Activation(activation, **kwargs)	Applies an activation function to input.
ELU([alpha])	Exponential Linear Unit (ELU)
GELU([approximation])	Gaussian Exponential Linear Unit (GELU)
LeakyReLU(alpha, **kwargs)	Leaky version of a Rectified Linear Unit.
PReLU([alpha_initializer, in_channels])	Parametric leaky version of a Rectified Linear Unit.
SELU(**kwargs)	Scaled Exponential Linear Unit (SELU)
SiLU(**kwargs)	Sigmoid Linear Units
Swish([beta])	Swish Activation function (SiLU with a hyperparameter)

class mxnet.gluon.nn.activations.Activation(activation, **kwargs)

Bases: HybridBlock

Applies an activation function to input.

Parameters:

activation (str) – Name of activation function to use. See Activation() for available choices.

Inputs:

• data: input tensor with arbitrary shape.

Outputs:

• out: output tensor with the same shape as data.

apply(fn)

Applies fn recursively to every child block as well as self.

Parameters:

fn (callable) – Function to be applied to each submodule, of form fn(block).

Return type:

this block

cast(dtype)

Cast this Block to use another data type.

Parameters:

dtype (str or numpy.dtype) – The new data type.

collect_params(select=None)

Returns a Dict containing this Block and all of its children’s Parameters(default), also can returns the select Dict which match some given regular expressions.

For example, collect the specified parameters in [‘conv1.weight’, ‘conv1.bias’, ‘fc.weight’, ‘fc.bias’]:

model.collect_params('conv1.weight|conv1.bias|fc.weight|fc.bias')

or collect all parameters whose names end with ‘weight’ or ‘bias’, this can be done using regular expressions:

model.collect_params('.*weight|.*bias')

Parameters:

select (str) – regular expressions

Return type:

The selected Dict

export(path, epoch=0, remove_amp_cast=True)

Export HybridBlock to json format that can be loaded by gluon.SymbolBlock.imports or the C++ interface.

Note

When there are only one input, it will have name data. When there Are more than one inputs, they will be named as data0, data1, etc.

Parameters:

• path (str or None) – Path to save model. Two files path-symbol.json and path-xxxx.params will be created, where xxxx is the 4 digits epoch number. If None, do not export to file but return Python Symbol object and corresponding dictionary of parameters.

• epoch (int) – Epoch number of saved model.

• remove_amp_cast (bool, optional) – Whether to remove the amp_cast and amp_multicast operators, before saving the model.

Returns:

• symbol_filename (str) – Filename to which model symbols were saved, including path prefix.

• params_filename (str) – Filename to which model parameters were saved, including path prefix.

forward(x)

Overrides the forward computation. Arguments must be mxnet.numpy.ndarray.

hybridize(active=True, partition_if_dynamic=True, static_alloc=False, static_shape=False, inline_limit=2, forward_bulk_size=None, backward_bulk_size=None)

Activates or deactivates HybridBlock s recursively. Has no effect on non-hybrid children.

Parameters:

• active (bool, default True) – Whether to turn hybrid on or off.

• partition_if_dynamic (bool, default False) – whether to partition the graph when dynamic shape op exists

• static_alloc (bool, default False) – Statically allocate memory to improve speed. Memory usage may increase.

• static_shape (bool, default False) – Optimize for invariant input shapes between iterations. Must also set static_alloc to True. Change of input shapes is still allowed but slower.

• inline_limit (optional int, default 2) – Maximum number of operators that can be inlined.

• forward_bulk_size (optional int, default None) – Segment size of bulk execution during forward pass.

• backward_bulk_size (optional int, default None) – Segment size of bulk execution during backward pass.

infer_shape(*args)

Infers shape of Parameters from inputs.

infer_type(*args)

Infers data type of Parameters from inputs.

initialize(init=<mxnet.initializer.Uniform object>, device=None, verbose=False, force_reinit=False)

Initializes Parameter s of this Block and its children.

Parameters:

• init (Initializer) – Global default Initializer to be used when Parameter.init() is None. Otherwise, Parameter.init() takes precedence.

• device (Device or list of Device) – Keeps a copy of Parameters on one or many device(s).

• verbose (bool, default False) – Whether to verbosely print out details on initialization.

• force_reinit (bool, default False) – Whether to force re-initialization if parameter is already initialized.

load(prefix)

Load a model saved using the save API

Reconfigures a model using the saved configuration. This function does not regenerate the model architecture. It resets each Block’s parameter UUIDs as they were when saved in order to match the names of the saved parameters.

This function assumes the Blocks in the model were created in the same order they were when the model was saved. This is because each Block is uniquely identified by Block class name and a unique ID in order (since its an OrderedDict) and uses the unique ID to denote that specific Block.

Assumes that the model is created in an identical order every time. If the model is not able to be recreated deterministically do not use this set of APIs to save/load your model.

For HybridBlocks, the cached_graph (Symbol & inputs) and settings are restored if it had been hybridized before saving.

Parameters:

prefix (str) – The prefix to use in filenames for loading this model: <prefix>-model.json and <prefix>-model.params

load_dict(param_dict, device=None, allow_missing=False, ignore_extra=False, cast_dtype=False, dtype_source='current')

Load parameters from dict

Parameters:

• param_dict (dict) – Dictionary containing model parameters

• device (Device, optional) – Device context on which the memory is allocated. Default is mxnet.device.current_device().

• allow_missing (bool, default False) – Whether to silently skip loading parameters not represented in the file.

• ignore_extra (bool, default False) – Whether to silently ignore parameters from the file that are not present in this dict.

• cast_dtype (bool, default False) – Cast the data type of the NDArray loaded from the checkpoint to the dtype provided by the Parameter if any

• dtype_source (str, default 'current') – must be in {‘current’, ‘saved’} Only valid if cast_dtype=True, specify the source of the dtype for casting the parameters

load_parameters(filename, device=None, allow_missing=False, ignore_extra=False, cast_dtype=False, dtype_source='current')

Load parameters from file previously saved by save_parameters.

Parameters:

• filename (str) – Path to parameter file.

• device (Device or list of Device, default cpu()) – Device(s) to initialize loaded parameters on.

• allow_missing (bool, default False) – Whether to silently skip loading parameters not represents in the file.

• ignore_extra (bool, default False) – Whether to silently ignore parameters from the file that are not present in this Block.

• cast_dtype (bool, default False) – Cast the data type of the NDArray loaded from the checkpoint to the dtype provided by the Parameter if any.

• dtype_source (str, default 'current') – must be in {‘current’, ‘saved’} Only valid if cast_dtype=True, specify the source of the dtype for casting the parameters

References

Saving and Loading Gluon Models

optimize_for(x, *args, backend=None, clear=False, partition_if_dynamic=True, static_alloc=False, static_shape=False, inline_limit=2, forward_bulk_size=None, backward_bulk_size=None, **kwargs)

Partitions the current HybridBlock and optimizes it for a given backend without executing a forward pass. Modifies the HybridBlock in-place.

Immediately partitions a HybridBlock using the specified backend. Combines the work done in the hybridize API with part of the work done in the forward pass without calling the CachedOp. Can be used in place of hybridize, afterwards export can be called or inference can be run. See README.md in example/extensions/lib_subgraph/README.md for more details.

Examples

# partition and then export to file block.optimize_for(x, backend=’myPart’) block.export(‘partitioned’)

# partition and then run inference block.optimize_for(x, backend=’myPart’) block(x)

Parameters:

• x (NDArray) – first input to model

• *args (NDArray) – other inputs to model

• backend (str) – The name of backend, as registered in SubgraphBackendRegistry, default None

• backend_opts (dict of user-specified options to pass to the backend for partitioning, optional) – Passed on to PrePartition and PostPartition functions of SubgraphProperty

• clear (bool, default False) – clears any previous optimizations

• partition_if_dynamic (bool, default False) – whether to partition the graph when dynamic shape op exists

• static_alloc (bool, default False) – Statically allocate memory to improve speed. Memory usage may increase.

• static_shape (bool, default False) – Optimize for invariant input shapes between iterations. Must also set static_alloc to True. Change of input shapes is still allowed but slower.

• inline_limit (optional int, default 2) – Maximum number of operators that can be inlined.

• forward_bulk_size (optional int, default None) – Segment size of bulk execution during forward pass.

• backward_bulk_size (optional int, default None) – Segment size of bulk execution during backward pass.

• **kwargs (The backend options, optional) – Passed on to PrePartition and PostPartition functions of SubgraphProperty

property params

Returns this Block’s parameter dictionary (does not include its children’s parameters).

register_child(block, name=None)

Registers block as a child of self. Block s assigned to self as attributes will be registered automatically.

register_forward_hook(hook)

Registers a forward hook on the block.

The hook function is called immediately after forward(). It should not modify the input or output.

Parameters:

hook (callable) – The forward hook function of form hook(block, input, output) -> None.

Return type:

mxnet.gluon.utils.HookHandle

register_forward_pre_hook(hook)

Registers a forward pre-hook on the block.

The hook function is called immediately before forward(). It should not modify the input or output.

Parameters:

hook (callable) – The forward hook function of form hook(block, input) -> None.

Return type:

mxnet.gluon.utils.HookHandle

register_op_hook(callback, monitor_all=False)

Install op hook for block recursively.

Parameters:

• callback (function) – Function called to inspect the values of the intermediate outputs of blocks after hybridization. It takes 3 parameters: name of the tensor being inspected (str) name of the operator producing or consuming that tensor (str) tensor being inspected (NDArray).

• monitor_all (bool, default False) – If True, monitor both input and output, otherwise monitor output only.

reset_ctx(ctx)

This function has been deprecated. Please refer to HybridBlock.reset_device.

reset_device(device)

Re-assign all Parameters to other devices. If the Block is hybridized, it will reset the _cached_op_args.

Parameters:

device (Device or list of Device, default device.current_device().) – Assign Parameter to given device. If device is a list of Device, a copy will be made for each device.

save(prefix)

Save the model architecture and parameters to load again later

Saves the model architecture as a nested dictionary where each Block in the model is a dictionary and its children are sub-dictionaries.

Each Block is uniquely identified by Block class name and a unique ID. We save each Block’s parameter UUID to restore later in order to match the saved parameters.

Recursively traverses a Block’s children in order (since its an OrderedDict) and uses the unique ID to denote that specific Block.

Assumes that the model is created in an identical order every time. If the model is not able to be recreated deterministically do not use this set of APIs to save/load your model.

For HybridBlocks, the cached_graph is saved (Symbol & inputs) if it has already been hybridized.

Parameters:

prefix (str) – The prefix to use in filenames for saving this model: <prefix>-model.json and <prefix>-model.params

save_parameters(filename, deduplicate=False)

Save parameters to file.

Saved parameters can only be loaded with load_parameters. Note that this method only saves parameters, not model structure. If you want to save model structures, please use HybridBlock.export().

Parameters:

• filename (str) – Path to file.

• deduplicate (bool, default False) – If True, save shared parameters only once. Otherwise, if a Block contains multiple sub-blocks that share parameters, each of the shared parameters will be separately saved for every sub-block.

References

Saving and Loading Gluon Models

setattr(name, value)

Set an attribute to a new value for all Parameters.

For example, set grad_req to null if you don’t need gradient w.r.t a model’s Parameters:

model.setattr('grad_req', 'null')

or change the learning rate multiplier:

model.setattr('lr_mult', 0.5)

Parameters:

• name (str) – Name of the attribute.

• value (valid type for attribute name) – The new value for the attribute.

share_parameters(shared)

Share parameters recursively inside the model.

For example, if you want dense1 to share dense0’s weights, you can do:

dense0 = nn.Dense(20)
dense1 = nn.Dense(20)
dense1.share_parameters(dense0.collect_params())

which equals to

dense1.weight = dense0.weight dense1.bias = dense0.bias

Note that unlike the load_parameters or load_dict functions, share_parameters results in the Parameter object being shared (or tied) between the models, whereas load_parameters or load_dict only set the value of the data dictionary of a model. If you call load_parameters or load_dict after share_parameters, the loaded value will be reflected in all networks that use the shared (or tied) Parameter object.

Parameters:

shared (Dict) – Dict of the shared parameters.

Return type:

this block

summary(*inputs)

Print the summary of the model’s output and parameters.

The network must have been initialized, and must not have been hybridized.

Parameters:

inputs (object) – Any input that the model supports. For any tensor in the input, only mxnet.ndarray.NDArray is supported.

zero_grad()

Sets all Parameters’ gradient buffer to 0.

class mxnet.gluon.nn.activations.ELU(alpha=1.0, **kwargs)

Bases: HybridBlock

Exponential Linear Unit (ELU)

“Fast and Accurate Deep Network Learning by Exponential Linear Units”, Clevert et al, 2016 https://arxiv.org/abs/1511.07289 Published as a conference paper at ICLR 2016

Parameters:

alpha (float) – The alpha parameter as described by Clevert et al, 2016

Inputs:

• data: input tensor with arbitrary shape.

Outputs:

• out: output tensor with the same shape as data.

apply(fn)

Applies fn recursively to every child block as well as self.

Parameters:

fn (callable) – Function to be applied to each submodule, of form fn(block).

Return type:

this block

cast(dtype)

Cast this Block to use another data type.

Parameters:

dtype (str or numpy.dtype) – The new data type.

collect_params(select=None)

Returns a Dict containing this Block and all of its children’s Parameters(default), also can returns the select Dict which match some given regular expressions.

For example, collect the specified parameters in [‘conv1.weight’, ‘conv1.bias’, ‘fc.weight’, ‘fc.bias’]:

model.collect_params('conv1.weight|conv1.bias|fc.weight|fc.bias')

or collect all parameters whose names end with ‘weight’ or ‘bias’, this can be done using regular expressions:

model.collect_params('.*weight|.*bias')

Parameters:

select (str) – regular expressions

Return type:

The selected Dict

export(path, epoch=0, remove_amp_cast=True)

Export HybridBlock to json format that can be loaded by gluon.SymbolBlock.imports or the C++ interface.

Note

When there are only one input, it will have name data. When there Are more than one inputs, they will be named as data0, data1, etc.

Parameters:

• path (str or None) – Path to save model. Two files path-symbol.json and path-xxxx.params will be created, where xxxx is the 4 digits epoch number. If None, do not export to file but return Python Symbol object and corresponding dictionary of parameters.

• epoch (int) – Epoch number of saved model.

• remove_amp_cast (bool, optional) – Whether to remove the amp_cast and amp_multicast operators, before saving the model.

Returns:

• symbol_filename (str) – Filename to which model symbols were saved, including path prefix.

• params_filename (str) – Filename to which model parameters were saved, including path prefix.

forward(x)

Overrides the forward computation. Arguments must be mxnet.numpy.ndarray.

hybridize(active=True, partition_if_dynamic=True, static_alloc=False, static_shape=False, inline_limit=2, forward_bulk_size=None, backward_bulk_size=None)

Activates or deactivates HybridBlock s recursively. Has no effect on non-hybrid children.

Parameters:

• active (bool, default True) – Whether to turn hybrid on or off.

• partition_if_dynamic (bool, default False) – whether to partition the graph when dynamic shape op exists

• static_alloc (bool, default False) – Statically allocate memory to improve speed. Memory usage may increase.

• static_shape (bool, default False) – Optimize for invariant input shapes between iterations. Must also set static_alloc to True. Change of input shapes is still allowed but slower.

• inline_limit (optional int, default 2) – Maximum number of operators that can be inlined.

• forward_bulk_size (optional int, default None) – Segment size of bulk execution during forward pass.

• backward_bulk_size (optional int, default None) – Segment size of bulk execution during backward pass.

infer_shape(*args)

Infers shape of Parameters from inputs.

infer_type(*args)

Infers data type of Parameters from inputs.

initialize(init=<mxnet.initializer.Uniform object>, device=None, verbose=False, force_reinit=False)

Initializes Parameter s of this Block and its children.

Parameters:

• init (Initializer) – Global default Initializer to be used when Parameter.init() is None. Otherwise, Parameter.init() takes precedence.

• device (Device or list of Device) – Keeps a copy of Parameters on one or many device(s).

• verbose (bool, default False) – Whether to verbosely print out details on initialization.

• force_reinit (bool, default False) – Whether to force re-initialization if parameter is already initialized.

load(prefix)

Load a model saved using the save API

Reconfigures a model using the saved configuration. This function does not regenerate the model architecture. It resets each Block’s parameter UUIDs as they were when saved in order to match the names of the saved parameters.

This function assumes the Blocks in the model were created in the same order they were when the model was saved. This is because each Block is uniquely identified by Block class name and a unique ID in order (since its an OrderedDict) and uses the unique ID to denote that specific Block.

Assumes that the model is created in an identical order every time. If the model is not able to be recreated deterministically do not use this set of APIs to save/load your model.

For HybridBlocks, the cached_graph (Symbol & inputs) and settings are restored if it had been hybridized before saving.

Parameters:

prefix (str) – The prefix to use in filenames for loading this model: <prefix>-model.json and <prefix>-model.params

load_dict(param_dict, device=None, allow_missing=False, ignore_extra=False, cast_dtype=False, dtype_source='current')

Load parameters from dict

Parameters:

• param_dict (dict) – Dictionary containing model parameters

• device (Device, optional) – Device context on which the memory is allocated. Default is mxnet.device.current_device().

• allow_missing (bool, default False) – Whether to silently skip loading parameters not represented in the file.

• ignore_extra (bool, default False) – Whether to silently ignore parameters from the file that are not present in this dict.

• cast_dtype (bool, default False) – Cast the data type of the NDArray loaded from the checkpoint to the dtype provided by the Parameter if any

• dtype_source (str, default 'current') – must be in {‘current’, ‘saved’} Only valid if cast_dtype=True, specify the source of the dtype for casting the parameters

load_parameters(filename, device=None, allow_missing=False, ignore_extra=False, cast_dtype=False, dtype_source='current')

Load parameters from file previously saved by save_parameters.

Parameters:

• filename (str) – Path to parameter file.

• device (Device or list of Device, default cpu()) – Device(s) to initialize loaded parameters on.

• allow_missing (bool, default False) – Whether to silently skip loading parameters not represents in the file.

• ignore_extra (bool, default False) – Whether to silently ignore parameters from the file that are not present in this Block.

• cast_dtype (bool, default False) – Cast the data type of the NDArray loaded from the checkpoint to the dtype provided by the Parameter if any.

• dtype_source (str, default 'current') – must be in {‘current’, ‘saved’} Only valid if cast_dtype=True, specify the source of the dtype for casting the parameters

References

Saving and Loading Gluon Models

optimize_for(x, *args, backend=None, clear=False, partition_if_dynamic=True, static_alloc=False, static_shape=False, inline_limit=2, forward_bulk_size=None, backward_bulk_size=None, **kwargs)

Partitions the current HybridBlock and optimizes it for a given backend without executing a forward pass. Modifies the HybridBlock in-place.

Immediately partitions a HybridBlock using the specified backend. Combines the work done in the hybridize API with part of the work done in the forward pass without calling the CachedOp. Can be used in place of hybridize, afterwards export can be called or inference can be run. See README.md in example/extensions/lib_subgraph/README.md for more details.

Examples

# partition and then export to file block.optimize_for(x, backend=’myPart’) block.export(‘partitioned’)

# partition and then run inference block.optimize_for(x, backend=’myPart’) block(x)

Parameters:

• x (NDArray) – first input to model

• *args (NDArray) – other inputs to model

• backend (str) – The name of backend, as registered in SubgraphBackendRegistry, default None

• backend_opts (dict of user-specified options to pass to the backend for partitioning, optional) – Passed on to PrePartition and PostPartition functions of SubgraphProperty

• clear (bool, default False) – clears any previous optimizations

• partition_if_dynamic (bool, default False) – whether to partition the graph when dynamic shape op exists

• static_alloc (bool, default False) – Statically allocate memory to improve speed. Memory usage may increase.

• static_shape (bool, default False) – Optimize for invariant input shapes between iterations. Must also set static_alloc to True. Change of input shapes is still allowed but slower.

• inline_limit (optional int, default 2) – Maximum number of operators that can be inlined.

• forward_bulk_size (optional int, default None) – Segment size of bulk execution during forward pass.

• backward_bulk_size (optional int, default None) – Segment size of bulk execution during backward pass.

• **kwargs (The backend options, optional) – Passed on to PrePartition and PostPartition functions of SubgraphProperty

property params

Returns this Block’s parameter dictionary (does not include its children’s parameters).

register_child(block, name=None)

Registers block as a child of self. Block s assigned to self as attributes will be registered automatically.

register_forward_hook(hook)

Registers a forward hook on the block.

The hook function is called immediately after forward(). It should not modify the input or output.

Parameters:

hook (callable) – The forward hook function of form hook(block, input, output) -> None.

Return type:

mxnet.gluon.utils.HookHandle

register_forward_pre_hook(hook)

Registers a forward pre-hook on the block.

The hook function is called immediately before forward(). It should not modify the input or output.

Parameters:

hook (callable) – The forward hook function of form hook(block, input) -> None.

Return type:

mxnet.gluon.utils.HookHandle

register_op_hook(callback, monitor_all=False)

Install op hook for block recursively.

Parameters:

• callback (function) – Function called to inspect the values of the intermediate outputs of blocks after hybridization. It takes 3 parameters: name of the tensor being inspected (str) name of the operator producing or consuming that tensor (str) tensor being inspected (NDArray).

• monitor_all (bool, default False) – If True, monitor both input and output, otherwise monitor output only.

reset_ctx(ctx)

This function has been deprecated. Please refer to HybridBlock.reset_device.

reset_device(device)

Re-assign all Parameters to other devices. If the Block is hybridized, it will reset the _cached_op_args.

Parameters:

device (Device or list of Device, default device.current_device().) – Assign Parameter to given device. If device is a list of Device, a copy will be made for each device.

save(prefix)

Save the model architecture and parameters to load again later

Saves the model architecture as a nested dictionary where each Block in the model is a dictionary and its children are sub-dictionaries.

Each Block is uniquely identified by Block class name and a unique ID. We save each Block’s parameter UUID to restore later in order to match the saved parameters.

Recursively traverses a Block’s children in order (since its an OrderedDict) and uses the unique ID to denote that specific Block.

Assumes that the model is created in an identical order every time. If the model is not able to be recreated deterministically do not use this set of APIs to save/load your model.

For HybridBlocks, the cached_graph is saved (Symbol & inputs) if it has already been hybridized.

Parameters:

prefix (str) – The prefix to use in filenames for saving this model: <prefix>-model.json and <prefix>-model.params

save_parameters(filename, deduplicate=False)

Save parameters to file.

Saved parameters can only be loaded with load_parameters. Note that this method only saves parameters, not model structure. If you want to save model structures, please use HybridBlock.export().

Parameters:

• filename (str) – Path to file.

• deduplicate (bool, default False) – If True, save shared parameters only once. Otherwise, if a Block contains multiple sub-blocks that share parameters, each of the shared parameters will be separately saved for every sub-block.

References

Saving and Loading Gluon Models

setattr(name, value)

Set an attribute to a new value for all Parameters.

For example, set grad_req to null if you don’t need gradient w.r.t a model’s Parameters:

model.setattr('grad_req', 'null')

or change the learning rate multiplier:

model.setattr('lr_mult', 0.5)

Parameters:

• name (str) – Name of the attribute.

• value (valid type for attribute name) – The new value for the attribute.

share_parameters(shared)

Share parameters recursively inside the model.

For example, if you want dense1 to share dense0’s weights, you can do:

dense0 = nn.Dense(20)
dense1 = nn.Dense(20)
dense1.share_parameters(dense0.collect_params())

which equals to

dense1.weight = dense0.weight dense1.bias = dense0.bias

Note that unlike the load_parameters or load_dict functions, share_parameters results in the Parameter object being shared (or tied) between the models, whereas load_parameters or load_dict only set the value of the data dictionary of a model. If you call load_parameters or load_dict after share_parameters, the loaded value will be reflected in all networks that use the shared (or tied) Parameter object.

Parameters:

shared (Dict) – Dict of the shared parameters.

Return type:

this block

summary(*inputs)

Print the summary of the model’s output and parameters.

The network must have been initialized, and must not have been hybridized.

Parameters:

inputs (object) – Any input that the model supports. For any tensor in the input, only mxnet.ndarray.NDArray is supported.

zero_grad()

Sets all Parameters’ gradient buffer to 0.

class mxnet.gluon.nn.activations.GELU(approximation='erf', **kwargs)

Bases: HybridBlock

Gaussian Exponential Linear Unit (GELU)

“Gaussian Error Linear Units (GELUs)”, Hendrycks et al, 2016 https://arxiv.org/abs/1606.08415

Parameters:

• approximation (string) – Which approximation of GELU calculation to use (erf or tanh).

• Inputs –

  • data: input tensor with arbitrary shape.

• Outputs –

  • out: output tensor with the same shape as data.

apply(fn)

Applies fn recursively to every child block as well as self.

Parameters:

fn (callable) – Function to be applied to each submodule, of form fn(block).

Return type:

this block

cast(dtype)

Cast this Block to use another data type.

Parameters:

dtype (str or numpy.dtype) – The new data type.

collect_params(select=None)

Returns a Dict containing this Block and all of its children’s Parameters(default), also can returns the select Dict which match some given regular expressions.

For example, collect the specified parameters in [‘conv1.weight’, ‘conv1.bias’, ‘fc.weight’, ‘fc.bias’]:

model.collect_params('conv1.weight|conv1.bias|fc.weight|fc.bias')

or collect all parameters whose names end with ‘weight’ or ‘bias’, this can be done using regular expressions:

model.collect_params('.*weight|.*bias')

Parameters:

select (str) – regular expressions

Return type:

The selected Dict

export(path, epoch=0, remove_amp_cast=True)

Export HybridBlock to json format that can be loaded by gluon.SymbolBlock.imports or the C++ interface.

Note

When there are only one input, it will have name data. When there Are more than one inputs, they will be named as data0, data1, etc.

Parameters:

• path (str or None) – Path to save model. Two files path-symbol.json and path-xxxx.params will be created, where xxxx is the 4 digits epoch number. If None, do not export to file but return Python Symbol object and corresponding dictionary of parameters.

• epoch (int) – Epoch number of saved model.

• remove_amp_cast (bool, optional) – Whether to remove the amp_cast and amp_multicast operators, before saving the model.

Returns:

• symbol_filename (str) – Filename to which model symbols were saved, including path prefix.

• params_filename (str) – Filename to which model parameters were saved, including path prefix.

forward(x)

Overrides the forward computation. Arguments must be mxnet.numpy.ndarray.

hybridize(active=True, partition_if_dynamic=True, static_alloc=False, static_shape=False, inline_limit=2, forward_bulk_size=None, backward_bulk_size=None)

Activates or deactivates HybridBlock s recursively. Has no effect on non-hybrid children.

Parameters:

• active (bool, default True) – Whether to turn hybrid on or off.

• partition_if_dynamic (bool, default False) – whether to partition the graph when dynamic shape op exists

• static_alloc (bool, default False) – Statically allocate memory to improve speed. Memory usage may increase.

• static_shape (bool, default False) – Optimize for invariant input shapes between iterations. Must also set static_alloc to True. Change of input shapes is still allowed but slower.

• inline_limit (optional int, default 2) – Maximum number of operators that can be inlined.

• forward_bulk_size (optional int, default None) – Segment size of bulk execution during forward pass.

• backward_bulk_size (optional int, default None) – Segment size of bulk execution during backward pass.

infer_shape(*args)

Infers shape of Parameters from inputs.

infer_type(*args)

Infers data type of Parameters from inputs.

initialize(init=<mxnet.initializer.Uniform object>, device=None, verbose=False, force_reinit=False)

Initializes Parameter s of this Block and its children.

Parameters:

• init (Initializer) – Global default Initializer to be used when Parameter.init() is None. Otherwise, Parameter.init() takes precedence.

• device (Device or list of Device) – Keeps a copy of Parameters on one or many device(s).

• verbose (bool, default False) – Whether to verbosely print out details on initialization.

• force_reinit (bool, default False) – Whether to force re-initialization if parameter is already initialized.

load(prefix)

Load a model saved using the save API

Reconfigures a model using the saved configuration. This function does not regenerate the model architecture. It resets each Block’s parameter UUIDs as they were when saved in order to match the names of the saved parameters.

This function assumes the Blocks in the model were created in the same order they were when the model was saved. This is because each Block is uniquely identified by Block class name and a unique ID in order (since its an OrderedDict) and uses the unique ID to denote that specific Block.

Assumes that the model is created in an identical order every time. If the model is not able to be recreated deterministically do not use this set of APIs to save/load your model.

For HybridBlocks, the cached_graph (Symbol & inputs) and settings are restored if it had been hybridized before saving.

Parameters:

prefix (str) – The prefix to use in filenames for loading this model: <prefix>-model.json and <prefix>-model.params

load_dict(param_dict, device=None, allow_missing=False, ignore_extra=False, cast_dtype=False, dtype_source='current')

Load parameters from dict

Parameters:

• param_dict (dict) – Dictionary containing model parameters

• device (Device, optional) – Device context on which the memory is allocated. Default is mxnet.device.current_device().

• allow_missing (bool, default False) – Whether to silently skip loading parameters not represented in the file.

• ignore_extra (bool, default False) – Whether to silently ignore parameters from the file that are not present in this dict.

• cast_dtype (bool, default False) – Cast the data type of the NDArray loaded from the checkpoint to the dtype provided by the Parameter if any

• dtype_source (str, default 'current') – must be in {‘current’, ‘saved’} Only valid if cast_dtype=True, specify the source of the dtype for casting the parameters

load_parameters(filename, device=None, allow_missing=False, ignore_extra=False, cast_dtype=False, dtype_source='current')

Load parameters from file previously saved by save_parameters.

Parameters:

• filename (str) – Path to parameter file.

• device (Device or list of Device, default cpu()) – Device(s) to initialize loaded parameters on.

• allow_missing (bool, default False) – Whether to silently skip loading parameters not represents in the file.

• ignore_extra (bool, default False) – Whether to silently ignore parameters from the file that are not present in this Block.

• cast_dtype (bool, default False) – Cast the data type of the NDArray loaded from the checkpoint to the dtype provided by the Parameter if any.

• dtype_source (str, default 'current') – must be in {‘current’, ‘saved’} Only valid if cast_dtype=True, specify the source of the dtype for casting the parameters

References

Saving and Loading Gluon Models

optimize_for(x, *args, backend=None, clear=False, partition_if_dynamic=True, static_alloc=False, static_shape=False, inline_limit=2, forward_bulk_size=None, backward_bulk_size=None, **kwargs)

Partitions the current HybridBlock and optimizes it for a given backend without executing a forward pass. Modifies the HybridBlock in-place.

Immediately partitions a HybridBlock using the specified backend. Combines the work done in the hybridize API with part of the work done in the forward pass without calling the CachedOp. Can be used in place of hybridize, afterwards export can be called or inference can be run. See README.md in example/extensions/lib_subgraph/README.md for more details.

Examples

# partition and then export to file block.optimize_for(x, backend=’myPart’) block.export(‘partitioned’)

# partition and then run inference block.optimize_for(x, backend=’myPart’) block(x)

Parameters:

• x (NDArray) – first input to model

• *args (NDArray) – other inputs to model

• backend (str) – The name of backend, as registered in SubgraphBackendRegistry, default None

• backend_opts (dict of user-specified options to pass to the backend for partitioning, optional) – Passed on to PrePartition and PostPartition functions of SubgraphProperty

• clear (bool, default False) – clears any previous optimizations

• partition_if_dynamic (bool, default False) – whether to partition the graph when dynamic shape op exists

• static_alloc (bool, default False) – Statically allocate memory to improve speed. Memory usage may increase.

• static_shape (bool, default False) – Optimize for invariant input shapes between iterations. Must also set static_alloc to True. Change of input shapes is still allowed but slower.

• inline_limit (optional int, default 2) – Maximum number of operators that can be inlined.

• forward_bulk_size (optional int, default None) – Segment size of bulk execution during forward pass.

• backward_bulk_size (optional int, default None) – Segment size of bulk execution during backward pass.

• **kwargs (The backend options, optional) – Passed on to PrePartition and PostPartition functions of SubgraphProperty

property params

Returns this Block’s parameter dictionary (does not include its children’s parameters).

register_child(block, name=None)

Registers block as a child of self. Block s assigned to self as attributes will be registered automatically.

register_forward_hook(hook)

Registers a forward hook on the block.

The hook function is called immediately after forward(). It should not modify the input or output.

Parameters:

hook (callable) – The forward hook function of form hook(block, input, output) -> None.

Return type:

mxnet.gluon.utils.HookHandle

register_forward_pre_hook(hook)

Registers a forward pre-hook on the block.

The hook function is called immediately before forward(). It should not modify the input or output.

Parameters:

hook (callable) – The forward hook function of form hook(block, input) -> None.

Return type:

mxnet.gluon.utils.HookHandle

register_op_hook(callback, monitor_all=False)

Install op hook for block recursively.

Parameters:

• callback (function) – Function called to inspect the values of the intermediate outputs of blocks after hybridization. It takes 3 parameters: name of the tensor being inspected (str) name of the operator producing or consuming that tensor (str) tensor being inspected (NDArray).

• monitor_all (bool, default False) – If True, monitor both input and output, otherwise monitor output only.

reset_ctx(ctx)

This function has been deprecated. Please refer to HybridBlock.reset_device.

reset_device(device)

Re-assign all Parameters to other devices. If the Block is hybridized, it will reset the _cached_op_args.

Parameters:

device (Device or list of Device, default device.current_device().) – Assign Parameter to given device. If device is a list of Device, a copy will be made for each device.

save(prefix)

Save the model architecture and parameters to load again later

Saves the model architecture as a nested dictionary where each Block in the model is a dictionary and its children are sub-dictionaries.

Each Block is uniquely identified by Block class name and a unique ID. We save each Block’s parameter UUID to restore later in order to match the saved parameters.

Recursively traverses a Block’s children in order (since its an OrderedDict) and uses the unique ID to denote that specific Block.

Assumes that the model is created in an identical order every time. If the model is not able to be recreated deterministically do not use this set of APIs to save/load your model.

For HybridBlocks, the cached_graph is saved (Symbol & inputs) if it has already been hybridized.

Parameters:

prefix (str) – The prefix to use in filenames for saving this model: <prefix>-model.json and <prefix>-model.params

save_parameters(filename, deduplicate=False)

Save parameters to file.

Saved parameters can only be loaded with load_parameters. Note that this method only saves parameters, not model structure. If you want to save model structures, please use HybridBlock.export().

Parameters:

• filename (str) – Path to file.

• deduplicate (bool, default False) – If True, save shared parameters only once. Otherwise, if a Block contains multiple sub-blocks that share parameters, each of the shared parameters will be separately saved for every sub-block.

References

Saving and Loading Gluon Models

setattr(name, value)

Set an attribute to a new value for all Parameters.

For example, set grad_req to null if you don’t need gradient w.r.t a model’s Parameters:

model.setattr('grad_req', 'null')

or change the learning rate multiplier:

model.setattr('lr_mult', 0.5)

Parameters:

• name (str) – Name of the attribute.

• value (valid type for attribute name) – The new value for the attribute.

share_parameters(shared)

Share parameters recursively inside the model.

For example, if you want dense1 to share dense0’s weights, you can do:

dense0 = nn.Dense(20)
dense1 = nn.Dense(20)
dense1.share_parameters(dense0.collect_params())

which equals to

dense1.weight = dense0.weight dense1.bias = dense0.bias

Note that unlike the load_parameters or load_dict functions, share_parameters results in the Parameter object being shared (or tied) between the models, whereas load_parameters or load_dict only set the value of the data dictionary of a model. If you call load_parameters or load_dict after share_parameters, the loaded value will be reflected in all networks that use the shared (or tied) Parameter object.

Parameters:

shared (Dict) – Dict of the shared parameters.

Return type:

this block

summary(*inputs)

Print the summary of the model’s output and parameters.

The network must have been initialized, and must not have been hybridized.

Parameters:

inputs (object) – Any input that the model supports. For any tensor in the input, only mxnet.ndarray.NDArray is supported.

zero_grad()

Sets all Parameters’ gradient buffer to 0.

class mxnet.gluon.nn.activations.LeakyReLU(alpha, **kwargs)

Bases: HybridBlock

Leaky version of a Rectified Linear Unit.

It allows a small gradient when the unit is not active

\[\begin{split}f\left(x\right) = \left\{ \begin{array}{lr} \alpha x & : x \lt 0 \\ x & : x \geq 0 \\ \end{array} \right.\\\end{split}\]

Parameters:

alpha (float) – slope coefficient for the negative half axis. Must be >= 0.

Inputs:

• data: input tensor with arbitrary shape.

Outputs:

• out: output tensor with the same shape as data.

apply(fn)

Applies fn recursively to every child block as well as self.

Parameters:

fn (callable) – Function to be applied to each submodule, of form fn(block).

Return type:

this block

cast(dtype)

Cast this Block to use another data type.

Parameters:

dtype (str or numpy.dtype) – The new data type.

collect_params(select=None)

Returns a Dict containing this Block and all of its children’s Parameters(default), also can returns the select Dict which match some given regular expressions.

For example, collect the specified parameters in [‘conv1.weight’, ‘conv1.bias’, ‘fc.weight’, ‘fc.bias’]:

model.collect_params('conv1.weight|conv1.bias|fc.weight|fc.bias')

or collect all parameters whose names end with ‘weight’ or ‘bias’, this can be done using regular expressions:

model.collect_params('.*weight|.*bias')

Parameters:

select (str) – regular expressions

Return type:

The selected Dict

export(path, epoch=0, remove_amp_cast=True)

Export HybridBlock to json format that can be loaded by gluon.SymbolBlock.imports or the C++ interface.

Note

When there are only one input, it will have name data. When there Are more than one inputs, they will be named as data0, data1, etc.

Parameters:

• path (str or None) – Path to save model. Two files path-symbol.json and path-xxxx.params will be created, where xxxx is the 4 digits epoch number. If None, do not export to file but return Python Symbol object and corresponding dictionary of parameters.

• epoch (int) – Epoch number of saved model.

• remove_amp_cast (bool, optional) – Whether to remove the amp_cast and amp_multicast operators, before saving the model.

Returns:

• symbol_filename (str) – Filename to which model symbols were saved, including path prefix.

• params_filename (str) – Filename to which model parameters were saved, including path prefix.

forward(x)

Overrides the forward computation. Arguments must be mxnet.numpy.ndarray.

hybridize(active=True, partition_if_dynamic=True, static_alloc=False, static_shape=False, inline_limit=2, forward_bulk_size=None, backward_bulk_size=None)

Activates or deactivates HybridBlock s recursively. Has no effect on non-hybrid children.

Parameters:

• active (bool, default True) – Whether to turn hybrid on or off.

• partition_if_dynamic (bool, default False) – whether to partition the graph when dynamic shape op exists

• static_alloc (bool, default False) – Statically allocate memory to improve speed. Memory usage may increase.

• static_shape (bool, default False) – Optimize for invariant input shapes between iterations. Must also set static_alloc to True. Change of input shapes is still allowed but slower.

• inline_limit (optional int, default 2) – Maximum number of operators that can be inlined.

• forward_bulk_size (optional int, default None) – Segment size of bulk execution during forward pass.

• backward_bulk_size (optional int, default None) – Segment size of bulk execution during backward pass.

infer_shape(*args)

Infers shape of Parameters from inputs.

infer_type(*args)

Infers data type of Parameters from inputs.

initialize(init=<mxnet.initializer.Uniform object>, device=None, verbose=False, force_reinit=False)

Initializes Parameter s of this Block and its children.

Parameters:

• init (Initializer) – Global default Initializer to be used when Parameter.init() is None. Otherwise, Parameter.init() takes precedence.

• device (Device or list of Device) – Keeps a copy of Parameters on one or many device(s).

• verbose (bool, default False) – Whether to verbosely print out details on initialization.

• force_reinit (bool, default False) – Whether to force re-initialization if parameter is already initialized.

load(prefix)

Load a model saved using the save API

Reconfigures a model using the saved configuration. This function does not regenerate the model architecture. It resets each Block’s parameter UUIDs as they were when saved in order to match the names of the saved parameters.

This function assumes the Blocks in the model were created in the same order they were when the model was saved. This is because each Block is uniquely identified by Block class name and a unique ID in order (since its an OrderedDict) and uses the unique ID to denote that specific Block.

Assumes that the model is created in an identical order every time. If the model is not able to be recreated deterministically do not use this set of APIs to save/load your model.

For HybridBlocks, the cached_graph (Symbol & inputs) and settings are restored if it had been hybridized before saving.

Parameters:

prefix (str) – The prefix to use in filenames for loading this model: <prefix>-model.json and <prefix>-model.params

load_dict(param_dict, device=None, allow_missing=False, ignore_extra=False, cast_dtype=False, dtype_source='current')

Load parameters from dict

Parameters:

• param_dict (dict) – Dictionary containing model parameters

• device (Device, optional) – Device context on which the memory is allocated. Default is mxnet.device.current_device().

• allow_missing (bool, default False) – Whether to silently skip loading parameters not represented in the file.

• ignore_extra (bool, default False) – Whether to silently ignore parameters from the file that are not present in this dict.

• cast_dtype (bool, default False) – Cast the data type of the NDArray loaded from the checkpoint to the dtype provided by the Parameter if any

• dtype_source (str, default 'current') – must be in {‘current’, ‘saved’} Only valid if cast_dtype=True, specify the source of the dtype for casting the parameters

load_parameters(filename, device=None, allow_missing=False, ignore_extra=False, cast_dtype=False, dtype_source='current')

Load parameters from file previously saved by save_parameters.

Parameters:

• filename (str) – Path to parameter file.

• device (Device or list of Device, default cpu()) – Device(s) to initialize loaded parameters on.

• allow_missing (bool, default False) – Whether to silently skip loading parameters not represents in the file.

• ignore_extra (bool, default False) – Whether to silently ignore parameters from the file that are not present in this Block.

• cast_dtype (bool, default False) – Cast the data type of the NDArray loaded from the checkpoint to the dtype provided by the Parameter if any.

• dtype_source (str, default 'current') – must be in {‘current’, ‘saved’} Only valid if cast_dtype=True, specify the source of the dtype for casting the parameters

References

Saving and Loading Gluon Models

optimize_for(x, *args, backend=None, clear=False, partition_if_dynamic=True, static_alloc=False, static_shape=False, inline_limit=2, forward_bulk_size=None, backward_bulk_size=None, **kwargs)

Partitions the current HybridBlock and optimizes it for a given backend without executing a forward pass. Modifies the HybridBlock in-place.

Immediately partitions a HybridBlock using the specified backend. Combines the work done in the hybridize API with part of the work done in the forward pass without calling the CachedOp. Can be used in place of hybridize, afterwards export can be called or inference can be run. See README.md in example/extensions/lib_subgraph/README.md for more details.

Examples

# partition and then export to file block.optimize_for(x, backend=’myPart’) block.export(‘partitioned’)

# partition and then run inference block.optimize_for(x, backend=’myPart’) block(x)

Parameters:

• x (NDArray) – first input to model

• *args (NDArray) – other inputs to model

• backend (str) – The name of backend, as registered in SubgraphBackendRegistry, default None

• backend_opts (dict of user-specified options to pass to the backend for partitioning, optional) – Passed on to PrePartition and PostPartition functions of SubgraphProperty

• clear (bool, default False) – clears any previous optimizations

• partition_if_dynamic (bool, default False) – whether to partition the graph when dynamic shape op exists

• static_alloc (bool, default False) – Statically allocate memory to improve speed. Memory usage may increase.

• static_shape (bool, default False) – Optimize for invariant input shapes between iterations. Must also set static_alloc to True. Change of input shapes is still allowed but slower.

• inline_limit (optional int, default 2) – Maximum number of operators that can be inlined.

• forward_bulk_size (optional int, default None) – Segment size of bulk execution during forward pass.

• backward_bulk_size (optional int, default None) – Segment size of bulk execution during backward pass.

• **kwargs (The backend options, optional) – Passed on to PrePartition and PostPartition functions of SubgraphProperty

property params

Returns this Block’s parameter dictionary (does not include its children’s parameters).

register_child(block, name=None)

Registers block as a child of self. Block s assigned to self as attributes will be registered automatically.

register_forward_hook(hook)

Registers a forward hook on the block.

The hook function is called immediately after forward(). It should not modify the input or output.

Parameters:

hook (callable) – The forward hook function of form hook(block, input, output) -> None.

Return type:

mxnet.gluon.utils.HookHandle

register_forward_pre_hook(hook)

Registers a forward pre-hook on the block.

The hook function is called immediately before forward(). It should not modify the input or output.

Parameters:

hook (callable) – The forward hook function of form hook(block, input) -> None.

Return type:

mxnet.gluon.utils.HookHandle

register_op_hook(callback, monitor_all=False)

Install op hook for block recursively.

Parameters:

• callback (function) – Function called to inspect the values of the intermediate outputs of blocks after hybridization. It takes 3 parameters: name of the tensor being inspected (str) name of the operator producing or consuming that tensor (str) tensor being inspected (NDArray).

• monitor_all (bool, default False) – If True, monitor both input and output, otherwise monitor output only.

reset_ctx(ctx)

This function has been deprecated. Please refer to HybridBlock.reset_device.

reset_device(device)

Re-assign all Parameters to other devices. If the Block is hybridized, it will reset the _cached_op_args.

Parameters:

device (Device or list of Device, default device.current_device().) – Assign Parameter to given device. If device is a list of Device, a copy will be made for each device.

save(prefix)

Save the model architecture and parameters to load again later

Saves the model architecture as a nested dictionary where each Block in the model is a dictionary and its children are sub-dictionaries.

Each Block is uniquely identified by Block class name and a unique ID. We save each Block’s parameter UUID to restore later in order to match the saved parameters.

Recursively traverses a Block’s children in order (since its an OrderedDict) and uses the unique ID to denote that specific Block.

Assumes that the model is created in an identical order every time. If the model is not able to be recreated deterministically do not use this set of APIs to save/load your model.

For HybridBlocks, the cached_graph is saved (Symbol & inputs) if it has already been hybridized.

Parameters:

prefix (str) – The prefix to use in filenames for saving this model: <prefix>-model.json and <prefix>-model.params

save_parameters(filename, deduplicate=False)

Save parameters to file.

Saved parameters can only be loaded with load_parameters. Note that this method only saves parameters, not model structure. If you want to save model structures, please use HybridBlock.export().

Parameters:

• filename (str) – Path to file.

• deduplicate (bool, default False) – If True, save shared parameters only once. Otherwise, if a Block contains multiple sub-blocks that share parameters, each of the shared parameters will be separately saved for every sub-block.

References

Saving and Loading Gluon Models

setattr(name, value)

Set an attribute to a new value for all Parameters.

For example, set grad_req to null if you don’t need gradient w.r.t a model’s Parameters:

model.setattr('grad_req', 'null')

or change the learning rate multiplier:

model.setattr('lr_mult', 0.5)

Parameters:

• name (str) – Name of the attribute.

• value (valid type for attribute name) – The new value for the attribute.

share_parameters(shared)

Share parameters recursively inside the model.

For example, if you want dense1 to share dense0’s weights, you can do:

dense0 = nn.Dense(20)
dense1 = nn.Dense(20)
dense1.share_parameters(dense0.collect_params())

which equals to

dense1.weight = dense0.weight dense1.bias = dense0.bias

Note that unlike the load_parameters or load_dict functions, share_parameters results in the Parameter object being shared (or tied) between the models, whereas load_parameters or load_dict only set the value of the data dictionary of a model. If you call load_parameters or load_dict after share_parameters, the loaded value will be reflected in all networks that use the shared (or tied) Parameter object.

Parameters:

shared (Dict) – Dict of the shared parameters.

Return type:

this block

summary(*inputs)

Print the summary of the model’s output and parameters.

The network must have been initialized, and must not have been hybridized.

Parameters:

inputs (object) – Any input that the model supports. For any tensor in the input, only mxnet.ndarray.NDArray is supported.

zero_grad()

Sets all Parameters’ gradient buffer to 0.

class mxnet.gluon.nn.activations.PReLU(alpha_initializer=<mxnet.initializer.Constant object>, in_channels=1, **kwargs)

Bases: HybridBlock

Parametric leaky version of a Rectified Linear Unit. <https://arxiv.org/abs/1502.01852>`_ paper.

It learns a gradient when the unit is not active

\[\begin{split}f\left(x\right) = \left\{ \begin{array}{lr} \alpha x & : x \lt 0 \\ x & : x \geq 0 \\ \end{array} \right.\\\end{split}\]

where alpha is a learned parameter.

Parameters:

• alpha_initializer (Initializer) – Initializer for the embeddings matrix.

• in_channels (int, default 1) – Number of channels (alpha parameters) to learn. Can either be 1 or n where n is the size of the second dimension of the input tensor.

• Inputs –

  • data: input tensor with arbitrary shape.

• Outputs –

  • out: output tensor with the same shape as data.

apply(fn)

Applies fn recursively to every child block as well as self.

Parameters:

fn (callable) – Function to be applied to each submodule, of form fn(block).

Return type:

this block

cast(dtype)

Cast this Block to use another data type.

Parameters:

dtype (str or numpy.dtype) – The new data type.

collect_params(select=None)

Returns a Dict containing this Block and all of its children’s Parameters(default), also can returns the select Dict which match some given regular expressions.

For example, collect the specified parameters in [‘conv1.weight’, ‘conv1.bias’, ‘fc.weight’, ‘fc.bias’]:

model.collect_params('conv1.weight|conv1.bias|fc.weight|fc.bias')

or collect all parameters whose names end with ‘weight’ or ‘bias’, this can be done using regular expressions:

model.collect_params('.*weight|.*bias')

Parameters:

select (str) – regular expressions

Return type:

The selected Dict

export(path, epoch=0, remove_amp_cast=True)

Export HybridBlock to json format that can be loaded by gluon.SymbolBlock.imports or the C++ interface.

Note

When there are only one input, it will have name data. When there Are more than one inputs, they will be named as data0, data1, etc.

Parameters:

• path (str or None) – Path to save model. Two files path-symbol.json and path-xxxx.params will be created, where xxxx is the 4 digits epoch number. If None, do not export to file but return Python Symbol object and corresponding dictionary of parameters.

• epoch (int) – Epoch number of saved model.

• remove_amp_cast (bool, optional) – Whether to remove the amp_cast and amp_multicast operators, before saving the model.

Returns:

• symbol_filename (str) – Filename to which model symbols were saved, including path prefix.

• params_filename (str) – Filename to which model parameters were saved, including path prefix.

forward(x)

Overrides the forward computation. Arguments must be mxnet.numpy.ndarray.

hybridize(active=True, partition_if_dynamic=True, static_alloc=False, static_shape=False, inline_limit=2, forward_bulk_size=None, backward_bulk_size=None)

Activates or deactivates HybridBlock s recursively. Has no effect on non-hybrid children.

Parameters:

• active (bool, default True) – Whether to turn hybrid on or off.

• partition_if_dynamic (bool, default False) – whether to partition the graph when dynamic shape op exists

• static_alloc (bool, default False) – Statically allocate memory to improve speed. Memory usage may increase.

• static_shape (bool, default False) – Optimize for invariant input shapes between iterations. Must also set static_alloc to True. Change of input shapes is still allowed but slower.

• inline_limit (optional int, default 2) – Maximum number of operators that can be inlined.

• forward_bulk_size (optional int, default None) – Segment size of bulk execution during forward pass.

• backward_bulk_size (optional int, default None) – Segment size of bulk execution during backward pass.

infer_shape(*args)

Infers shape of Parameters from inputs.

infer_type(*args)

Infers data type of Parameters from inputs.

initialize(init=<mxnet.initializer.Uniform object>, device=None, verbose=False, force_reinit=False)

Initializes Parameter s of this Block and its children.

Parameters:

• init (Initializer) – Global default Initializer to be used when Parameter.init() is None. Otherwise, Parameter.init() takes precedence.

• device (Device or list of Device) – Keeps a copy of Parameters on one or many device(s).

• verbose (bool, default False) – Whether to verbosely print out details on initialization.

• force_reinit (bool, default False) – Whether to force re-initialization if parameter is already initialized.

load(prefix)

Load a model saved using the save API

Reconfigures a model using the saved configuration. This function does not regenerate the model architecture. It resets each Block’s parameter UUIDs as they were when saved in order to match the names of the saved parameters.

This function assumes the Blocks in the model were created in the same order they were when the model was saved. This is because each Block is uniquely identified by Block class name and a unique ID in order (since its an OrderedDict) and uses the unique ID to denote that specific Block.

Assumes that the model is created in an identical order every time. If the model is not able to be recreated deterministically do not use this set of APIs to save/load your model.

For HybridBlocks, the cached_graph (Symbol & inputs) and settings are restored if it had been hybridized before saving.

Parameters:

prefix (str) – The prefix to use in filenames for loading this model: <prefix>-model.json and <prefix>-model.params

load_dict(param_dict, device=None, allow_missing=False, ignore_extra=False, cast_dtype=False, dtype_source='current')

Load parameters from dict

Parameters:

• param_dict (dict) – Dictionary containing model parameters

• device (Device, optional) – Device context on which the memory is allocated. Default is mxnet.device.current_device().

• allow_missing (bool, default False) – Whether to silently skip loading parameters not represented in the file.

• ignore_extra (bool, default False) – Whether to silently ignore parameters from the file that are not present in this dict.

• cast_dtype (bool, default False) – Cast the data type of the NDArray loaded from the checkpoint to the dtype provided by the Parameter if any

• dtype_source (str, default 'current') – must be in {‘current’, ‘saved’} Only valid if cast_dtype=True, specify the source of the dtype for casting the parameters

load_parameters(filename, device=None, allow_missing=False, ignore_extra=False, cast_dtype=False, dtype_source='current')

Load parameters from file previously saved by save_parameters.

Parameters:

• filename (str) – Path to parameter file.

• device (Device or list of Device, default cpu()) – Device(s) to initialize loaded parameters on.

• allow_missing (bool, default False) – Whether to silently skip loading parameters not represents in the file.

• ignore_extra (bool, default False) – Whether to silently ignore parameters from the file that are not present in this Block.

• cast_dtype (bool, default False) – Cast the data type of the NDArray loaded from the checkpoint to the dtype provided by the Parameter if any.

• dtype_source (str, default 'current') – must be in {‘current’, ‘saved’} Only valid if cast_dtype=True, specify the source of the dtype for casting the parameters

References

Saving and Loading Gluon Models

optimize_for(x, *args, backend=None, clear=False, partition_if_dynamic=True, static_alloc=False, static_shape=False, inline_limit=2, forward_bulk_size=None, backward_bulk_size=None, **kwargs)

Partitions the current HybridBlock and optimizes it for a given backend without executing a forward pass. Modifies the HybridBlock in-place.

Immediately partitions a HybridBlock using the specified backend. Combines the work done in the hybridize API with part of the work done in the forward pass without calling the CachedOp. Can be used in place of hybridize, afterwards export can be called or inference can be run. See README.md in example/extensions/lib_subgraph/README.md for more details.

Examples

# partition and then export to file block.optimize_for(x, backend=’myPart’) block.export(‘partitioned’)

# partition and then run inference block.optimize_for(x, backend=’myPart’) block(x)

Parameters:

• x (NDArray) – first input to model

• *args (NDArray) – other inputs to model

• backend (str) – The name of backend, as registered in SubgraphBackendRegistry, default None

• backend_opts (dict of user-specified options to pass to the backend for partitioning, optional) – Passed on to PrePartition and PostPartition functions of SubgraphProperty

• clear (bool, default False) – clears any previous optimizations

• partition_if_dynamic (bool, default False) – whether to partition the graph when dynamic shape op exists

• static_alloc (bool, default False) – Statically allocate memory to improve speed. Memory usage may increase.

• static_shape (bool, default False) – Optimize for invariant input shapes between iterations. Must also set static_alloc to True. Change of input shapes is still allowed but slower.

• inline_limit (optional int, default 2) – Maximum number of operators that can be inlined.

• forward_bulk_size (optional int, default None) – Segment size of bulk execution during forward pass.

• backward_bulk_size (optional int, default None) – Segment size of bulk execution during backward pass.

• **kwargs (The backend options, optional) – Passed on to PrePartition and PostPartition functions of SubgraphProperty

property params

Returns this Block’s parameter dictionary (does not include its children’s parameters).

register_child(block, name=None)

Registers block as a child of self. Block s assigned to self as attributes will be registered automatically.

register_forward_hook(hook)

Registers a forward hook on the block.

The hook function is called immediately after forward(). It should not modify the input or output.

Parameters:

hook (callable) – The forward hook function of form hook(block, input, output) -> None.

Return type:

mxnet.gluon.utils.HookHandle

register_forward_pre_hook(hook)

Registers a forward pre-hook on the block.

The hook function is called immediately before forward(). It should not modify the input or output.

Parameters:

hook (callable) – The forward hook function of form hook(block, input) -> None.

Return type:

mxnet.gluon.utils.HookHandle

register_op_hook(callback, monitor_all=False)

Install op hook for block recursively.

Parameters:

• callback (function) – Function called to inspect the values of the intermediate outputs of blocks after hybridization. It takes 3 parameters: name of the tensor being inspected (str) name of the operator producing or consuming that tensor (str) tensor being inspected (NDArray).

• monitor_all (bool, default False) – If True, monitor both input and output, otherwise monitor output only.

reset_ctx(ctx)

This function has been deprecated. Please refer to HybridBlock.reset_device.

reset_device(device)

Re-assign all Parameters to other devices. If the Block is hybridized, it will reset the _cached_op_args.

Parameters:

device (Device or list of Device, default device.current_device().) – Assign Parameter to given device. If device is a list of Device, a copy will be made for each device.

save(prefix)

Save the model architecture and parameters to load again later

Saves the model architecture as a nested dictionary where each Block in the model is a dictionary and its children are sub-dictionaries.

Each Block is uniquely identified by Block class name and a unique ID. We save each Block’s parameter UUID to restore later in order to match the saved parameters.

Recursively traverses a Block’s children in order (since its an OrderedDict) and uses the unique ID to denote that specific Block.

Assumes that the model is created in an identical order every time. If the model is not able to be recreated deterministically do not use this set of APIs to save/load your model.

For HybridBlocks, the cached_graph is saved (Symbol & inputs) if it has already been hybridized.

Parameters:

prefix (str) – The prefix to use in filenames for saving this model: <prefix>-model.json and <prefix>-model.params

save_parameters(filename, deduplicate=False)

Save parameters to file.

Saved parameters can only be loaded with load_parameters. Note that this method only saves parameters, not model structure. If you want to save model structures, please use HybridBlock.export().

Parameters:

• filename (str) – Path to file.

• deduplicate (bool, default False) – If True, save shared parameters only once. Otherwise, if a Block contains multiple sub-blocks that share parameters, each of the shared parameters will be separately saved for every sub-block.

References

Saving and Loading Gluon Models

setattr(name, value)

Set an attribute to a new value for all Parameters.

For example, set grad_req to null if you don’t need gradient w.r.t a model’s Parameters:

model.setattr('grad_req', 'null')

or change the learning rate multiplier:

model.setattr('lr_mult', 0.5)

Parameters:

• name (str) – Name of the attribute.

• value (valid type for attribute name) – The new value for the attribute.

share_parameters(shared)

Share parameters recursively inside the model.

For example, if you want dense1 to share dense0’s weights, you can do:

dense0 = nn.Dense(20)
dense1 = nn.Dense(20)
dense1.share_parameters(dense0.collect_params())

which equals to

dense1.weight = dense0.weight dense1.bias = dense0.bias

Note that unlike the load_parameters or load_dict functions, share_parameters results in the Parameter object being shared (or tied) between the models, whereas load_parameters or load_dict only set the value of the data dictionary of a model. If you call load_parameters or load_dict after share_parameters, the loaded value will be reflected in all networks that use the shared (or tied) Parameter object.

Parameters:

shared (Dict) – Dict of the shared parameters.

Return type:

this block

summary(*inputs)

Print the summary of the model’s output and parameters.

The network must have been initialized, and must not have been hybridized.

Parameters:

inputs (object) – Any input that the model supports. For any tensor in the input, only mxnet.ndarray.NDArray is supported.

zero_grad()

Sets all Parameters’ gradient buffer to 0.

class mxnet.gluon.nn.activations.SELU(**kwargs)

Bases: HybridBlock

Scaled Exponential Linear Unit (SELU)

“Self-Normalizing Neural Networks”, Klambauer et al, 2017 https://arxiv.org/abs/1706.02515

Inputs:

• data: input tensor with arbitrary shape.

Outputs:

• out: output tensor with the same shape as data.

apply(fn)

Applies fn recursively to every child block as well as self.

Parameters:

fn (callable) – Function to be applied to each submodule, of form fn(block).

Return type:

this block

cast(dtype)

Cast this Block to use another data type.

Parameters:

dtype (str or numpy.dtype) – The new data type.

collect_params(select=None)

Returns a Dict containing this Block and all of its children’s Parameters(default), also can returns the select Dict which match some given regular expressions.

For example, collect the specified parameters in [‘conv1.weight’, ‘conv1.bias’, ‘fc.weight’, ‘fc.bias’]:

model.collect_params('conv1.weight|conv1.bias|fc.weight|fc.bias')

or collect all parameters whose names end with ‘weight’ or ‘bias’, this can be done using regular expressions:

model.collect_params('.*weight|.*bias')

Parameters:

select (str) – regular expressions

Return type:

The selected Dict

export(path, epoch=0, remove_amp_cast=True)

Export HybridBlock to json format that can be loaded by gluon.SymbolBlock.imports or the C++ interface.

Note

When there are only one input, it will have name data. When there Are more than one inputs, they will be named as data0, data1, etc.

Parameters:

• path (str or None) – Path to save model. Two files path-symbol.json and path-xxxx.params will be created, where xxxx is the 4 digits epoch number. If None, do not export to file but return Python Symbol object and corresponding dictionary of parameters.

• epoch (int) – Epoch number of saved model.

• remove_amp_cast (bool, optional) – Whether to remove the amp_cast and amp_multicast operators, before saving the model.

Returns:

• symbol_filename (str) – Filename to which model symbols were saved, including path prefix.

• params_filename (str) – Filename to which model parameters were saved, including path prefix.

forward(x)

Overrides the forward computation. Arguments must be mxnet.numpy.ndarray.

hybridize(active=True, partition_if_dynamic=True, static_alloc=False, static_shape=False, inline_limit=2, forward_bulk_size=None, backward_bulk_size=None)

Activates or deactivates HybridBlock s recursively. Has no effect on non-hybrid children.

Parameters:

• active (bool, default True) – Whether to turn hybrid on or off.

• partition_if_dynamic (bool, default False) – whether to partition the graph when dynamic shape op exists

• static_alloc (bool, default False) – Statically allocate memory to improve speed. Memory usage may increase.

• static_shape (bool, default False) – Optimize for invariant input shapes between iterations. Must also set static_alloc to True. Change of input shapes is still allowed but slower.

• inline_limit (optional int, default 2) – Maximum number of operators that can be inlined.

• forward_bulk_size (optional int, default None) – Segment size of bulk execution during forward pass.

• backward_bulk_size (optional int, default None) – Segment size of bulk execution during backward pass.

infer_shape(*args)

Infers shape of Parameters from inputs.

infer_type(*args)

Infers data type of Parameters from inputs.

initialize(init=<mxnet.initializer.Uniform object>, device=None, verbose=False, force_reinit=False)

Initializes Parameter s of this Block and its children.

Parameters:

• init (Initializer) – Global default Initializer to be used when Parameter.init() is None. Otherwise, Parameter.init() takes precedence.

• device (Device or list of Device) – Keeps a copy of Parameters on one or many device(s).

• verbose (bool, default False) – Whether to verbosely print out details on initialization.

• force_reinit (bool, default False) – Whether to force re-initialization if parameter is already initialized.

load(prefix)

Load a model saved using the save API

Reconfigures a model using the saved configuration. This function does not regenerate the model architecture. It resets each Block’s parameter UUIDs as they were when saved in order to match the names of the saved parameters.

This function assumes the Blocks in the model were created in the same order they were when the model was saved. This is because each Block is uniquely identified by Block class name and a unique ID in order (since its an OrderedDict) and uses the unique ID to denote that specific Block.

Assumes that the model is created in an identical order every time. If the model is not able to be recreated deterministically do not use this set of APIs to save/load your model.

For HybridBlocks, the cached_graph (Symbol & inputs) and settings are restored if it had been hybridized before saving.

Parameters:

prefix (str) – The prefix to use in filenames for loading this model: <prefix>-model.json and <prefix>-model.params

load_dict(param_dict, device=None, allow_missing=False, ignore_extra=False, cast_dtype=False, dtype_source='current')

Load parameters from dict

Parameters:

• param_dict (dict) – Dictionary containing model parameters

• device (Device, optional) – Device context on which the memory is allocated. Default is mxnet.device.current_device().

• allow_missing (bool, default False) – Whether to silently skip loading parameters not represented in the file.

• ignore_extra (bool, default False) – Whether to silently ignore parameters from the file that are not present in this dict.

• cast_dtype (bool, default False) – Cast the data type of the NDArray loaded from the checkpoint to the dtype provided by the Parameter if any

• dtype_source (str, default 'current') – must be in {‘current’, ‘saved’} Only valid if cast_dtype=True, specify the source of the dtype for casting the parameters

load_parameters(filename, device=None, allow_missing=False, ignore_extra=False, cast_dtype=False, dtype_source='current')

Load parameters from file previously saved by save_parameters.

Parameters:

• filename (str) – Path to parameter file.

• device (Device or list of Device, default cpu()) – Device(s) to initialize loaded parameters on.

• allow_missing (bool, default False) – Whether to silently skip loading parameters not represents in the file.

• ignore_extra (bool, default False) – Whether to silently ignore parameters from the file that are not present in this Block.

• cast_dtype (bool, default False) – Cast the data type of the NDArray loaded from the checkpoint to the dtype provided by the Parameter if any.

• dtype_source (str, default 'current') – must be in {‘current’, ‘saved’} Only valid if cast_dtype=True, specify the source of the dtype for casting the parameters

References

Saving and Loading Gluon Models

optimize_for(x, *args, backend=None, clear=False, partition_if_dynamic=True, static_alloc=False, static_shape=False, inline_limit=2, forward_bulk_size=None, backward_bulk_size=None, **kwargs)

Partitions the current HybridBlock and optimizes it for a given backend without executing a forward pass. Modifies the HybridBlock in-place.

Immediately partitions a HybridBlock using the specified backend. Combines the work done in the hybridize API with part of the work done in the forward pass without calling the CachedOp. Can be used in place of hybridize, afterwards export can be called or inference can be run. See README.md in example/extensions/lib_subgraph/README.md for more details.

Examples

# partition and then export to file block.optimize_for(x, backend=’myPart’) block.export(‘partitioned’)

# partition and then run inference block.optimize_for(x, backend=’myPart’) block(x)

Parameters:

• x (NDArray) – first input to model

• *args (NDArray) – other inputs to model

• backend (str) – The name of backend, as registered in SubgraphBackendRegistry, default None

• backend_opts (dict of user-specified options to pass to the backend for partitioning, optional) – Passed on to PrePartition and PostPartition functions of SubgraphProperty

• clear (bool, default False) – clears any previous optimizations

• partition_if_dynamic (bool, default False) – whether to partition the graph when dynamic shape op exists

• static_alloc (bool, default False) – Statically allocate memory to improve speed. Memory usage may increase.

• static_shape (bool, default False) – Optimize for invariant input shapes between iterations. Must also set static_alloc to True. Change of input shapes is still allowed but slower.

• inline_limit (optional int, default 2) – Maximum number of operators that can be inlined.

• forward_bulk_size (optional int, default None) – Segment size of bulk execution during forward pass.

• backward_bulk_size (optional int, default None) – Segment size of bulk execution during backward pass.

• **kwargs (The backend options, optional) – Passed on to PrePartition and PostPartition functions of SubgraphProperty

property params

Returns this Block’s parameter dictionary (does not include its children’s parameters).

register_child(block, name=None)

Registers block as a child of self. Block s assigned to self as attributes will be registered automatically.

register_forward_hook(hook)

Registers a forward hook on the block.

The hook function is called immediately after forward(). It should not modify the input or output.

Parameters:

hook (callable) – The forward hook function of form hook(block, input, output) -> None.

Return type:

mxnet.gluon.utils.HookHandle

register_forward_pre_hook(hook)

Registers a forward pre-hook on the block.

The hook function is called immediately before forward(). It should not modify the input or output.

Parameters:

hook (callable) – The forward hook function of form hook(block, input) -> None.

Return type:

mxnet.gluon.utils.HookHandle

register_op_hook(callback, monitor_all=False)

Install op hook for block recursively.

Parameters:

• callback (function) – Function called to inspect the values of the intermediate outputs of blocks after hybridization. It takes 3 parameters: name of the tensor being inspected (str) name of the operator producing or consuming that tensor (str) tensor being inspected (NDArray).

• monitor_all (bool, default False) – If True, monitor both input and output, otherwise monitor output only.

reset_ctx(ctx)

This function has been deprecated. Please refer to HybridBlock.reset_device.

reset_device(device)

Re-assign all Parameters to other devices. If the Block is hybridized, it will reset the _cached_op_args.

Parameters:

device (Device or list of Device, default device.current_device().) – Assign Parameter to given device. If device is a list of Device, a copy will be made for each device.

save(prefix)

Save the model architecture and parameters to load again later

Saves the model architecture as a nested dictionary where each Block in the model is a dictionary and its children are sub-dictionaries.

Each Block is uniquely identified by Block class name and a unique ID. We save each Block’s parameter UUID to restore later in order to match the saved parameters.

Recursively traverses a Block’s children in order (since its an OrderedDict) and uses the unique ID to denote that specific Block.

Assumes that the model is created in an identical order every time. If the model is not able to be recreated deterministically do not use this set of APIs to save/load your model.

For HybridBlocks, the cached_graph is saved (Symbol & inputs) if it has already been hybridized.

Parameters:

prefix (str) – The prefix to use in filenames for saving this model: <prefix>-model.json and <prefix>-model.params

save_parameters(filename, deduplicate=False)

Save parameters to file.

Saved parameters can only be loaded with load_parameters. Note that this method only saves parameters, not model structure. If you want to save model structures, please use HybridBlock.export().

Parameters:

• filename (str) – Path to file.

• deduplicate (bool, default False) – If True, save shared parameters only once. Otherwise, if a Block contains multiple sub-blocks that share parameters, each of the shared parameters will be separately saved for every sub-block.

References

Saving and Loading Gluon Models

setattr(name, value)

Set an attribute to a new value for all Parameters.

For example, set grad_req to null if you don’t need gradient w.r.t a model’s Parameters:

model.setattr('grad_req', 'null')

or change the learning rate multiplier:

model.setattr('lr_mult', 0.5)

Parameters:

• name (str) – Name of the attribute.

• value (valid type for attribute name) – The new value for the attribute.

share_parameters(shared)

Share parameters recursively inside the model.

For example, if you want dense1 to share dense0’s weights, you can do:

dense0 = nn.Dense(20)
dense1 = nn.Dense(20)
dense1.share_parameters(dense0.collect_params())

which equals to

dense1.weight = dense0.weight dense1.bias = dense0.bias

Note that unlike the load_parameters or load_dict functions, share_parameters results in the Parameter object being shared (or tied) between the models, whereas load_parameters or load_dict only set the value of the data dictionary of a model. If you call load_parameters or load_dict after share_parameters, the loaded value will be reflected in all networks that use the shared (or tied) Parameter object.

Parameters:

shared (Dict) – Dict of the shared parameters.

Return type:

this block

summary(*inputs)

Print the summary of the model’s output and parameters.

The network must have been initialized, and must not have been hybridized.

Parameters:

inputs (object) – Any input that the model supports. For any tensor in the input, only mxnet.ndarray.NDArray is supported.

zero_grad()

Sets all Parameters’ gradient buffer to 0.

class mxnet.gluon.nn.activations.SiLU(**kwargs)

Bases: HybridBlock

Sigmoid Linear Units

Originally proposed “Gaussian Error Linear Units (GELUs)”, Hendrycks et al, 2016 https://arxiv.org/abs/1606.08415

Parameters:

beta (float) – silu(x) = x * sigmoid(x)

Inputs:

• data: input tensor with arbitrary shape.

Outputs:

• out: output tensor with the same shape as data.

apply(fn)

Applies fn recursively to every child block as well as self.

Parameters:

fn (callable) – Function to be applied to each submodule, of form fn(block).

Return type:

this block

cast(dtype)

Cast this Block to use another data type.

Parameters:

dtype (str or numpy.dtype) – The new data type.

collect_params(select=None)

Returns a Dict containing this Block and all of its children’s Parameters(default), also can returns the select Dict which match some given regular expressions.

For example, collect the specified parameters in [‘conv1.weight’, ‘conv1.bias’, ‘fc.weight’, ‘fc.bias’]:

model.collect_params('conv1.weight|conv1.bias|fc.weight|fc.bias')

or collect all parameters whose names end with ‘weight’ or ‘bias’, this can be done using regular expressions:

model.collect_params('.*weight|.*bias')

Parameters:

select (str) – regular expressions

Return type:

The selected Dict

export(path, epoch=0, remove_amp_cast=True)

Export HybridBlock to json format that can be loaded by gluon.SymbolBlock.imports or the C++ interface.

Note

When there are only one input, it will have name data. When there Are more than one inputs, they will be named as data0, data1, etc.

Parameters:

• path (str or None) – Path to save model. Two files path-symbol.json and path-xxxx.params will be created, where xxxx is the 4 digits epoch number. If None, do not export to file but return Python Symbol object and corresponding dictionary of parameters.

• epoch (int) – Epoch number of saved model.

• remove_amp_cast (bool, optional) – Whether to remove the amp_cast and amp_multicast operators, before saving the model.

Returns:

• symbol_filename (str) – Filename to which model symbols were saved, including path prefix.

• params_filename (str) – Filename to which model parameters were saved, including path prefix.

forward(x)

Overrides the forward computation. Arguments must be mxnet.numpy.ndarray.

hybridize(active=True, partition_if_dynamic=True, static_alloc=False, static_shape=False, inline_limit=2, forward_bulk_size=None, backward_bulk_size=None)

Activates or deactivates HybridBlock s recursively. Has no effect on non-hybrid children.

Parameters:

• active (bool, default True) – Whether to turn hybrid on or off.

• partition_if_dynamic (bool, default False) – whether to partition the graph when dynamic shape op exists

• static_alloc (bool, default False) – Statically allocate memory to improve speed. Memory usage may increase.

• static_shape (bool, default False) – Optimize for invariant input shapes between iterations. Must also set static_alloc to True. Change of input shapes is still allowed but slower.

• inline_limit (optional int, default 2) – Maximum number of operators that can be inlined.

• forward_bulk_size (optional int, default None) – Segment size of bulk execution during forward pass.

• backward_bulk_size (optional int, default None) – Segment size of bulk execution during backward pass.

infer_shape(*args)

Infers shape of Parameters from inputs.

infer_type(*args)

Infers data type of Parameters from inputs.

initialize(init=<mxnet.initializer.Uniform object>, device=None, verbose=False, force_reinit=False)

Initializes Parameter s of this Block and its children.

Parameters:

• init (Initializer) – Global default Initializer to be used when Parameter.init() is None. Otherwise, Parameter.init() takes precedence.

• device (Device or list of Device) – Keeps a copy of Parameters on one or many device(s).

• verbose (bool, default False) – Whether to verbosely print out details on initialization.

• force_reinit (bool, default False) – Whether to force re-initialization if parameter is already initialized.

load(prefix)

Load a model saved using the save API

Reconfigures a model using the saved configuration. This function does not regenerate the model architecture. It resets each Block’s parameter UUIDs as they were when saved in order to match the names of the saved parameters.

This function assumes the Blocks in the model were created in the same order they were when the model was saved. This is because each Block is uniquely identified by Block class name and a unique ID in order (since its an OrderedDict) and uses the unique ID to denote that specific Block.

Assumes that the model is created in an identical order every time. If the model is not able to be recreated deterministically do not use this set of APIs to save/load your model.

For HybridBlocks, the cached_graph (Symbol & inputs) and settings are restored if it had been hybridized before saving.

Parameters:

prefix (str) – The prefix to use in filenames for loading this model: <prefix>-model.json and <prefix>-model.params

load_dict(param_dict, device=None, allow_missing=False, ignore_extra=False, cast_dtype=False, dtype_source='current')

Load parameters from dict

Parameters:

• param_dict (dict) – Dictionary containing model parameters

• device (Device, optional) – Device context on which the memory is allocated. Default is mxnet.device.current_device().

• allow_missing (bool, default False) – Whether to silently skip loading parameters not represented in the file.

• ignore_extra (bool, default False) – Whether to silently ignore parameters from the file that are not present in this dict.

• cast_dtype (bool, default False) – Cast the data type of the NDArray loaded from the checkpoint to the dtype provided by the Parameter if any

• dtype_source (str, default 'current') – must be in {‘current’, ‘saved’} Only valid if cast_dtype=True, specify the source of the dtype for casting the parameters

load_parameters(filename, device=None, allow_missing=False, ignore_extra=False, cast_dtype=False, dtype_source='current')

Load parameters from file previously saved by save_parameters.

Parameters:

• filename (str) – Path to parameter file.

• device (Device or list of Device, default cpu()) – Device(s) to initialize loaded parameters on.

• allow_missing (bool, default False) – Whether to silently skip loading parameters not represents in the file.

• ignore_extra (bool, default False) – Whether to silently ignore parameters from the file that are not present in this Block.

• cast_dtype (bool, default False) – Cast the data type of the NDArray loaded from the checkpoint to the dtype provided by the Parameter if any.

• dtype_source (str, default 'current') – must be in {‘current’, ‘saved’} Only valid if cast_dtype=True, specify the source of the dtype for casting the parameters

References

Saving and Loading Gluon Models

optimize_for(x, *args, backend=None, clear=False, partition_if_dynamic=True, static_alloc=False, static_shape=False, inline_limit=2, forward_bulk_size=None, backward_bulk_size=None, **kwargs)

Partitions the current HybridBlock and optimizes it for a given backend without executing a forward pass. Modifies the HybridBlock in-place.

Immediately partitions a HybridBlock using the specified backend. Combines the work done in the hybridize API with part of the work done in the forward pass without calling the CachedOp. Can be used in place of hybridize, afterwards export can be called or inference can be run. See README.md in example/extensions/lib_subgraph/README.md for more details.

Examples

# partition and then export to file block.optimize_for(x, backend=’myPart’) block.export(‘partitioned’)

# partition and then run inference block.optimize_for(x, backend=’myPart’) block(x)

Parameters:

• x (NDArray) – first input to model

• *args (NDArray) – other inputs to model

• backend (str) – The name of backend, as registered in SubgraphBackendRegistry, default None

• backend_opts (dict of user-specified options to pass to the backend for partitioning, optional) – Passed on to PrePartition and PostPartition functions of SubgraphProperty

• clear (bool, default False) – clears any previous optimizations

• partition_if_dynamic (bool, default False) – whether to partition the graph when dynamic shape op exists

• static_alloc (bool, default False) – Statically allocate memory to improve speed. Memory usage may increase.

• static_shape (bool, default False) – Optimize for invariant input shapes between iterations. Must also set static_alloc to True. Change of input shapes is still allowed but slower.

• inline_limit (optional int, default 2) – Maximum number of operators that can be inlined.

• forward_bulk_size (optional int, default None) – Segment size of bulk execution during forward pass.

• backward_bulk_size (optional int, default None) – Segment size of bulk execution during backward pass.

• **kwargs (The backend options, optional) – Passed on to PrePartition and PostPartition functions of SubgraphProperty

property params

Returns this Block’s parameter dictionary (does not include its children’s parameters).

register_child(block, name=None)

Registers block as a child of self. Block s assigned to self as attributes will be registered automatically.

register_forward_hook(hook)

Registers a forward hook on the block.

The hook function is called immediately after forward(). It should not modify the input or output.

Parameters:

hook (callable) – The forward hook function of form hook(block, input, output) -> None.

Return type:

mxnet.gluon.utils.HookHandle

register_forward_pre_hook(hook)

Registers a forward pre-hook on the block.

The hook function is called immediately before forward(). It should not modify the input or output.

Parameters:

hook (callable) – The forward hook function of form hook(block, input) -> None.

Return type:

mxnet.gluon.utils.HookHandle

register_op_hook(callback, monitor_all=False)

Install op hook for block recursively.

Parameters:

• callback (function) – Function called to inspect the values of the intermediate outputs of blocks after hybridization. It takes 3 parameters: name of the tensor being inspected (str) name of the operator producing or consuming that tensor (str) tensor being inspected (NDArray).

• monitor_all (bool, default False) – If True, monitor both input and output, otherwise monitor output only.

reset_ctx(ctx)

This function has been deprecated. Please refer to HybridBlock.reset_device.

reset_device(device)

Re-assign all Parameters to other devices. If the Block is hybridized, it will reset the _cached_op_args.

Parameters:

device (Device or list of Device, default device.current_device().) – Assign Parameter to given device. If device is a list of Device, a copy will be made for each device.

save(prefix)

Save the model architecture and parameters to load again later

Saves the model architecture as a nested dictionary where each Block in the model is a dictionary and its children are sub-dictionaries.

Each Block is uniquely identified by Block class name and a unique ID. We save each Block’s parameter UUID to restore later in order to match the saved parameters.

Recursively traverses a Block’s children in order (since its an OrderedDict) and uses the unique ID to denote that specific Block.

Assumes that the model is created in an identical order every time. If the model is not able to be recreated deterministically do not use this set of APIs to save/load your model.

For HybridBlocks, the cached_graph is saved (Symbol & inputs) if it has already been hybridized.

Parameters:

prefix (str) – The prefix to use in filenames for saving this model: <prefix>-model.json and <prefix>-model.params

save_parameters(filename, deduplicate=False)

Save parameters to file.

Saved parameters can only be loaded with load_parameters. Note that this method only saves parameters, not model structure. If you want to save model structures, please use HybridBlock.export().

Parameters:

• filename (str) – Path to file.

• deduplicate (bool, default False) – If True, save shared parameters only once. Otherwise, if a Block contains multiple sub-blocks that share parameters, each of the shared parameters will be separately saved for every sub-block.

References

Saving and Loading Gluon Models

setattr(name, value)

Set an attribute to a new value for all Parameters.

For example, set grad_req to null if you don’t need gradient w.r.t a model’s Parameters:

model.setattr('grad_req', 'null')

or change the learning rate multiplier:

model.setattr('lr_mult', 0.5)

Parameters:

• name (str) – Name of the attribute.

• value (valid type for attribute name) – The new value for the attribute.

share_parameters(shared)

Share parameters recursively inside the model.

For example, if you want dense1 to share dense0’s weights, you can do:

dense0 = nn.Dense(20)
dense1 = nn.Dense(20)
dense1.share_parameters(dense0.collect_params())

which equals to

dense1.weight = dense0.weight dense1.bias = dense0.bias

Note that unlike the load_parameters or load_dict functions, share_parameters results in the Parameter object being shared (or tied) between the models, whereas load_parameters or load_dict only set the value of the data dictionary of a model. If you call load_parameters or load_dict after share_parameters, the loaded value will be reflected in all networks that use the shared (or tied) Parameter object.

Parameters:

shared (Dict) – Dict of the shared parameters.

Return type:

this block

summary(*inputs)

Print the summary of the model’s output and parameters.

The network must have been initialized, and must not have been hybridized.

Parameters:

inputs (object) – Any input that the model supports. For any tensor in the input, only mxnet.ndarray.NDArray is supported.

zero_grad()

Sets all Parameters’ gradient buffer to 0.

class mxnet.gluon.nn.activations.Swish(beta=1.0, **kwargs)

Bases: HybridBlock

Swish Activation function (SiLU with a hyperparameter)

https://arxiv.org/pdf/1710.05941.pdf

Parameters:

beta (float) – swish(x) = x * sigmoid(beta*x)

Inputs:

• data: input tensor with arbitrary shape.

Outputs:

• out: output tensor with the same shape as data.

apply(fn)

Applies fn recursively to every child block as well as self.

Parameters:

fn (callable) – Function to be applied to each submodule, of form fn(block).

Return type:

this block

cast(dtype)

Cast this Block to use another data type.

Parameters:

dtype (str or numpy.dtype) – The new data type.

collect_params(select=None)

Returns a Dict containing this Block and all of its children’s Parameters(default), also can returns the select Dict which match some given regular expressions.

For example, collect the specified parameters in [‘conv1.weight’, ‘conv1.bias’, ‘fc.weight’, ‘fc.bias’]:

model.collect_params('conv1.weight|conv1.bias|fc.weight|fc.bias')

or collect all parameters whose names end with ‘weight’ or ‘bias’, this can be done using regular expressions:

model.collect_params('.*weight|.*bias')

Parameters:

select (str) – regular expressions

Return type:

The selected Dict

export(path, epoch=0, remove_amp_cast=True)

Export HybridBlock to json format that can be loaded by gluon.SymbolBlock.imports or the C++ interface.

Note

When there are only one input, it will have name data. When there Are more than one inputs, they will be named as data0, data1, etc.

Parameters:

• path (str or None) – Path to save model. Two files path-symbol.json and path-xxxx.params will be created, where xxxx is the 4 digits epoch number. If None, do not export to file but return Python Symbol object and corresponding dictionary of parameters.

• epoch (int) – Epoch number of saved model.

• remove_amp_cast (bool, optional) – Whether to remove the amp_cast and amp_multicast operators, before saving the model.

Returns:

• symbol_filename (str) – Filename to which model symbols were saved, including path prefix.

• params_filename (str) – Filename to which model parameters were saved, including path prefix.

forward(x)

Overrides the forward computation. Arguments must be mxnet.numpy.ndarray.

hybridize(active=True, partition_if_dynamic=True, static_alloc=False, static_shape=False, inline_limit=2, forward_bulk_size=None, backward_bulk_size=None)

Activates or deactivates HybridBlock s recursively. Has no effect on non-hybrid children.

Parameters:

• active (bool, default True) – Whether to turn hybrid on or off.

• partition_if_dynamic (bool, default False) – whether to partition the graph when dynamic shape op exists

• static_alloc (bool, default False) – Statically allocate memory to improve speed. Memory usage may increase.

• static_shape (bool, default False) – Optimize for invariant input shapes between iterations. Must also set static_alloc to True. Change of input shapes is still allowed but slower.

• inline_limit (optional int, default 2) – Maximum number of operators that can be inlined.

• forward_bulk_size (optional int, default None) – Segment size of bulk execution during forward pass.

• backward_bulk_size (optional int, default None) – Segment size of bulk execution during backward pass.

infer_shape(*args)

Infers shape of Parameters from inputs.

infer_type(*args)

Infers data type of Parameters from inputs.

initialize(init=<mxnet.initializer.Uniform object>, device=None, verbose=False, force_reinit=False)

Initializes Parameter s of this Block and its children.

Parameters:

• init (Initializer) – Global default Initializer to be used when Parameter.init() is None. Otherwise, Parameter.init() takes precedence.

• device (Device or list of Device) – Keeps a copy of Parameters on one or many device(s).

• verbose (bool, default False) – Whether to verbosely print out details on initialization.

• force_reinit (bool, default False) – Whether to force re-initialization if parameter is already initialized.

load(prefix)

Load a model saved using the save API

Reconfigures a model using the saved configuration. This function does not regenerate the model architecture. It resets each Block’s parameter UUIDs as they were when saved in order to match the names of the saved parameters.

This function assumes the Blocks in the model were created in the same order they were when the model was saved. This is because each Block is uniquely identified by Block class name and a unique ID in order (since its an OrderedDict) and uses the unique ID to denote that specific Block.

Assumes that the model is created in an identical order every time. If the model is not able to be recreated deterministically do not use this set of APIs to save/load your model.

For HybridBlocks, the cached_graph (Symbol & inputs) and settings are restored if it had been hybridized before saving.

Parameters:

prefix (str) – The prefix to use in filenames for loading this model: <prefix>-model.json and <prefix>-model.params

load_dict(param_dict, device=None, allow_missing=False, ignore_extra=False, cast_dtype=False, dtype_source='current')

Load parameters from dict

Parameters:

• param_dict (dict) – Dictionary containing model parameters

• device (Device, optional) – Device context on which the memory is allocated. Default is mxnet.device.current_device().

• allow_missing (bool, default False) – Whether to silently skip loading parameters not represented in the file.

• ignore_extra (bool, default False) – Whether to silently ignore parameters from the file that are not present in this dict.

• cast_dtype (bool, default False) – Cast the data type of the NDArray loaded from the checkpoint to the dtype provided by the Parameter if any

• dtype_source (str, default 'current') – must be in {‘current’, ‘saved’} Only valid if cast_dtype=True, specify the source of the dtype for casting the parameters

load_parameters(filename, device=None, allow_missing=False, ignore_extra=False, cast_dtype=False, dtype_source='current')

Load parameters from file previously saved by save_parameters.

Parameters:

• filename (str) – Path to parameter file.

• device (Device or list of Device, default cpu()) – Device(s) to initialize loaded parameters on.

• allow_missing (bool, default False) – Whether to silently skip loading parameters not represents in the file.

• ignore_extra (bool, default False) – Whether to silently ignore parameters from the file that are not present in this Block.

• cast_dtype (bool, default False) – Cast the data type of the NDArray loaded from the checkpoint to the dtype provided by the Parameter if any.

• dtype_source (str, default 'current') – must be in {‘current’, ‘saved’} Only valid if cast_dtype=True, specify the source of the dtype for casting the parameters

References

Saving and Loading Gluon Models

optimize_for(x, *args, backend=None, clear=False, partition_if_dynamic=True, static_alloc=False, static_shape=False, inline_limit=2, forward_bulk_size=None, backward_bulk_size=None, **kwargs)

Partitions the current HybridBlock and optimizes it for a given backend without executing a forward pass. Modifies the HybridBlock in-place.

Immediately partitions a HybridBlock using the specified backend. Combines the work done in the hybridize API with part of the work done in the forward pass without calling the CachedOp. Can be used in place of hybridize, afterwards export can be called or inference can be run. See README.md in example/extensions/lib_subgraph/README.md for more details.

Examples

# partition and then export to file block.optimize_for(x, backend=’myPart’) block.export(‘partitioned’)

# partition and then run inference block.optimize_for(x, backend=’myPart’) block(x)

Parameters:

• x (NDArray) – first input to model

• *args (NDArray) – other inputs to model

• backend (str) – The name of backend, as registered in SubgraphBackendRegistry, default None

• backend_opts (dict of user-specified options to pass to the backend for partitioning, optional) – Passed on to PrePartition and PostPartition functions of SubgraphProperty

• clear (bool, default False) – clears any previous optimizations

• partition_if_dynamic (bool, default False) – whether to partition the graph when dynamic shape op exists

• static_alloc (bool, default False) – Statically allocate memory to improve speed. Memory usage may increase.

• static_shape (bool, default False) – Optimize for invariant input shapes between iterations. Must also set static_alloc to True. Change of input shapes is still allowed but slower.

• inline_limit (optional int, default 2) – Maximum number of operators that can be inlined.

• forward_bulk_size (optional int, default None) – Segment size of bulk execution during forward pass.

• backward_bulk_size (optional int, default None) – Segment size of bulk execution during backward pass.

• **kwargs (The backend options, optional) – Passed on to PrePartition and PostPartition functions of SubgraphProperty

property params

Returns this Block’s parameter dictionary (does not include its children’s parameters).

register_child(block, name=None)

Registers block as a child of self. Block s assigned to self as attributes will be registered automatically.

register_forward_hook(hook)

Registers a forward hook on the block.

The hook function is called immediately after forward(). It should not modify the input or output.

Parameters:

hook (callable) – The forward hook function of form hook(block, input, output) -> None.

Return type:

mxnet.gluon.utils.HookHandle

register_forward_pre_hook(hook)

Registers a forward pre-hook on the block.

The hook function is called immediately before forward(). It should not modify the input or output.

Parameters:

hook (callable) – The forward hook function of form hook(block, input) -> None.

Return type:

mxnet.gluon.utils.HookHandle

register_op_hook(callback, monitor_all=False)

Install op hook for block recursively.

Parameters:

• callback (function) – Function called to inspect the values of the intermediate outputs of blocks after hybridization. It takes 3 parameters: name of the tensor being inspected (str) name of the operator producing or consuming that tensor (str) tensor being inspected (NDArray).

• monitor_all (bool, default False) – If True, monitor both input and output, otherwise monitor output only.

reset_ctx(ctx)

This function has been deprecated. Please refer to HybridBlock.reset_device.

reset_device(device)

Re-assign all Parameters to other devices. If the Block is hybridized, it will reset the _cached_op_args.

Parameters:

device (Device or list of Device, default device.current_device().) – Assign Parameter to given device. If device is a list of Device, a copy will be made for each device.

save(prefix)

Save the model architecture and parameters to load again later

Saves the model architecture as a nested dictionary where each Block in the model is a dictionary and its children are sub-dictionaries.

Each Block is uniquely identified by Block class name and a unique ID. We save each Block’s parameter UUID to restore later in order to match the saved parameters.

Recursively traverses a Block’s children in order (since its an OrderedDict) and uses the unique ID to denote that specific Block.

Assumes that the model is created in an identical order every time. If the model is not able to be recreated deterministically do not use this set of APIs to save/load your model.

For HybridBlocks, the cached_graph is saved (Symbol & inputs) if it has already been hybridized.

Parameters:

prefix (str) – The prefix to use in filenames for saving this model: <prefix>-model.json and <prefix>-model.params

save_parameters(filename, deduplicate=False)

Save parameters to file.

Saved parameters can only be loaded with load_parameters. Note that this method only saves parameters, not model structure. If you want to save model structures, please use HybridBlock.export().

Parameters:

• filename (str) – Path to file.

• deduplicate (bool, default False) – If True, save shared parameters only once. Otherwise, if a Block contains multiple sub-blocks that share parameters, each of the shared parameters will be separately saved for every sub-block.

References

Saving and Loading Gluon Models

setattr(name, value)

Set an attribute to a new value for all Parameters.

For example, set grad_req to null if you don’t need gradient w.r.t a model’s Parameters:

model.setattr('grad_req', 'null')

or change the learning rate multiplier:

model.setattr('lr_mult', 0.5)

Parameters:

• name (str) – Name of the attribute.

• value (valid type for attribute name) – The new value for the attribute.

share_parameters(shared)

Share parameters recursively inside the model.

For example, if you want dense1 to share dense0’s weights, you can do:

dense0 = nn.Dense(20)
dense1 = nn.Dense(20)
dense1.share_parameters(dense0.collect_params())

which equals to

dense1.weight = dense0.weight dense1.bias = dense0.bias

Note that unlike the load_parameters or load_dict functions, share_parameters results in the Parameter object being shared (or tied) between the models, whereas load_parameters or load_dict only set the value of the data dictionary of a model. If you call load_parameters or load_dict after share_parameters, the loaded value will be reflected in all networks that use the shared (or tied) Parameter object.

Parameters:

shared (Dict) – Dict of the shared parameters.

Return type:

this block

summary(*inputs)

Print the summary of the model’s output and parameters.

The network must have been initialized, and must not have been hybridized.

Parameters:

inputs (object) – Any input that the model supports. For any tensor in the input, only mxnet.ndarray.NDArray is supported.

zero_grad()

Sets all Parameters’ gradient buffer to 0.