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module.py
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module.py
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# --------------------------------------------------------
# Deformable Convolutional Networks
# Copyright (c) 2016 by Contributors
# Copyright (c) 2017 Microsoft
# Licensed under The Apache-2.0 License [see LICENSE for details]
# Modified by Yuwen Xiong
# --------------------------------------------------------
"""A `MutableModule` implement the `BaseModule` API, and allows input shape
varying with training iterations. If shapes vary, executors will rebind,
using shared arrays from the initial module binded with maximum shape.
"""
import time
import logging
import warnings
from mxnet import context as ctx
from mxnet.initializer import Uniform, InitDesc
from mxnet.module.base_module import BaseModule, _check_input_names, _parse_data_desc, _as_list
from mxnet.model import _create_kvstore, _initialize_kvstore, _update_params, _update_params_on_kvstore, load_checkpoint, BatchEndParam
from mxnet import metric
from .DataParallelExecutorGroup import DataParallelExecutorGroup
from mxnet import ndarray as nd
from mxnet import optimizer as opt
class Module(BaseModule):
"""Module is a basic module that wrap a `Symbol`. It is functionally the same
as the `FeedForward` model, except under the module API.
Parameters
----------
symbol : Symbol
data_names : list of str
Default is `('data')` for a typical model used in image classification.
label_names : list of str
Default is `('softmax_label')` for a typical model used in image
classification.
logger : Logger
Default is `logging`.
context : Context or list of Context
Default is `cpu()`.
work_load_list : list of number
Default `None`, indicating uniform workload.
fixed_param_names: list of str
Default `None`, indicating no network parameters are fixed.
state_names : list of str
states are similar to data and label, but not provided by data iterator.
Instead they are initialized to 0 and can be set by set_states()
"""
def __init__(self, symbol, data_names=('data',), label_names=('softmax_label',),
logger=logging, context=ctx.cpu(), work_load_list=None,
fixed_param_names=None, state_names=None):
super(Module, self).__init__(logger=logger)
if isinstance(context, ctx.Context):
context = [context]
self._context = context
if work_load_list is None:
work_load_list = [1] * len(self._context)
assert len(work_load_list) == len(self._context)
self._work_load_list = work_load_list
self._symbol = symbol
data_names = list(data_names) if data_names is not None else []
label_names = list(label_names) if label_names is not None else []
state_names = list(state_names) if state_names is not None else []
fixed_param_names = list(fixed_param_names) if fixed_param_names is not None else []
_check_input_names(symbol, data_names, "data", True)
_check_input_names(symbol, label_names, "label", False)
_check_input_names(symbol, state_names, "state", True)
_check_input_names(symbol, fixed_param_names, "fixed_param", True)
arg_names = symbol.list_arguments()
input_names = data_names + label_names + state_names
self._param_names = [x for x in arg_names if x not in input_names]
self._fixed_param_names = fixed_param_names
self._aux_names = symbol.list_auxiliary_states()
self._data_names = data_names
self._label_names = label_names
self._state_names = state_names
self._output_names = symbol.list_outputs()
self._arg_params = None
self._aux_params = None
self._params_dirty = False
self._optimizer = None
self._kvstore = None
self._update_on_kvstore = None
self._updater = None
self._preload_opt_states = None
self._grad_req = None
self._exec_group = None
self._data_shapes = None
self._label_shapes = None
@staticmethod
def load(prefix, epoch, load_optimizer_states=False, **kwargs):
"""Create a model from previously saved checkpoint.
Parameters
----------
prefix : str
path prefix of saved model files. You should have
"prefix-symbol.json", "prefix-xxxx.params", and
optionally "prefix-xxxx.states", where xxxx is the
epoch number.
epoch : int
epoch to load.
load_optimizer_states : bool
whether to load optimizer states. Checkpoint needs
to have been made with save_optimizer_states=True.
data_names : list of str
Default is `('data')` for a typical model used in image classification.
label_names : list of str
Default is `('softmax_label')` for a typical model used in image
classification.
logger : Logger
Default is `logging`.
context : Context or list of Context
Default is `cpu()`.
work_load_list : list of number
Default `None`, indicating uniform workload.
fixed_param_names: list of str
Default `None`, indicating no network parameters are fixed.
"""
sym, args, auxs = load_checkpoint(prefix, epoch)
mod = Module(symbol=sym, **kwargs)
mod._arg_params = args
mod._aux_params = auxs
mod.params_initialized = True
if load_optimizer_states:
mod._preload_opt_states = '%s-%04d.states'%(prefix, epoch)
return mod
def save_checkpoint(self, prefix, epoch, save_optimizer_states=False):
"""Save current progress to checkpoint.
Use mx.callback.module_checkpoint as epoch_end_callback to save during training.
Parameters
----------
prefix : str
The file prefix to checkpoint to
epoch : int
The current epoch number
save_optimizer_states : bool
Whether to save optimizer states for continue training
"""
self._symbol.save('%s-symbol.json'%prefix)
param_name = '%s-%04d.params' % (prefix, epoch)
self.save_params(param_name)
logging.info('Saved checkpoint to \"%s\"', param_name)
if save_optimizer_states:
state_name = '%s-%04d.states' % (prefix, epoch)
self.save_optimizer_states(state_name)
logging.info('Saved optimizer state to \"%s\"', state_name)
def _reset_bind(self):
"""Internal function to reset binded state."""
self.binded = False
self._exec_group = None
self._data_shapes = None
self._label_shapes = None
@property
def data_names(self):
"""A list of names for data required by this module."""
return self._data_names
@property
def label_names(self):
"""A list of names for labels required by this module."""
return self._label_names
@property
def output_names(self):
"""A list of names for the outputs of this module."""
return self._output_names
@property
def data_shapes(self):
"""Get data shapes.
Returns
-------
A list of `(name, shape)` pairs.
"""
assert self.binded
return self._data_shapes
@property
def label_shapes(self):
"""Get label shapes.
Returns
-------
A list of `(name, shape)` pairs. The return value could be `None` if
the module does not need labels, or if the module is not binded for
training (in this case, label information is not available).
"""
assert self.binded
return self._label_shapes
@property
def output_shapes(self):
"""Get output shapes.
Returns
-------
A list of `(name, shape)` pairs.
"""
assert self.binded
return self._exec_group.get_output_shapes()
def get_params(self):
"""Get current parameters.
Returns
-------
`(arg_params, aux_params)`, each a dictionary of name to parameters (in
`NDArray`) mapping.
"""
assert self.binded and self.params_initialized
if self._params_dirty:
self._sync_params_from_devices()
return (self._arg_params, self._aux_params)
def init_params(self, initializer=Uniform(0.01), arg_params=None, aux_params=None,
allow_missing=False, force_init=False):
"""Initialize the parameters and auxiliary states.
Parameters
----------
initializer : Initializer
Called to initialize parameters if needed.
arg_params : dict
If not None, should be a dictionary of existing arg_params. Initialization
will be copied from that.
aux_params : dict
If not None, should be a dictionary of existing aux_params. Initialization
will be copied from that.
allow_missing : bool
If true, params could contain missing values, and the initializer will be
called to fill those missing params.
force_init : bool
If true, will force re-initialize even if already initialized.
"""
if self.params_initialized and not force_init:
warnings.warn("Parameters already initialized and force_init=False. "
"init_params call ignored.", stacklevel=2)
return
assert self.binded, 'call bind before initializing the parameters'
def _impl(name, arr, cache):
"""Internal helper for parameter initialization"""
if cache is not None:
if name in cache:
cache_arr = cache[name]
# just in case the cached array is just the target itself
if cache_arr is not arr:
cache_arr.copyto(arr)
else:
if not allow_missing:
raise RuntimeError("%s is not presented" % name)
if initializer != None:
initializer(name, arr)
else:
initializer(name, arr)
attrs = self._symbol.attr_dict()
for name, arr in self._arg_params.items():
desc = InitDesc(name, attrs.get(name, None))
_impl(desc, arr, arg_params)
for name, arr in self._aux_params.items():
desc = InitDesc(name, attrs.get(name, None))
_impl(desc, arr, aux_params)
self.params_initialized = True
self._params_dirty = False
# copy the initialized parameters to devices
self._exec_group.set_params(self._arg_params, self._aux_params)
def set_params(self, arg_params, aux_params, allow_missing=False, force_init=True):
"""Assign parameter and aux state values.
Parameters
----------
arg_params : dict
Dictionary of name to value (`NDArray`) mapping.
aux_params : dict
Dictionary of name to value (`NDArray`) mapping.
allow_missing : bool
If true, params could contain missing values, and the initializer will be
called to fill those missing params.
force_init : bool
If true, will force re-initialize even if already initialized.
Examples
--------
An example of setting module parameters::
>>> sym, arg_params, aux_params = \
>>> mx.model.load_checkpoint(model_prefix, n_epoch_load)
>>> mod.set_params(arg_params=arg_params, aux_params=aux_params)
"""
if not allow_missing:
self.init_params(initializer=None, arg_params=arg_params, aux_params=aux_params,
allow_missing=allow_missing, force_init=force_init)
return
if self.params_initialized and not force_init:
warnings.warn("Parameters already initialized and force_init=False. "
"set_params call ignored.", stacklevel=2)
return
self._exec_group.set_params(arg_params, aux_params)
# because we didn't update self._arg_params, they are dirty now.
self._params_dirty = True
self.params_initialized = True
def bind(self, data_shapes, label_shapes=None, for_training=True,
inputs_need_grad=False, force_rebind=False, shared_module=None,
grad_req='write'):
"""Bind the symbols to construct executors. This is necessary before one
can perform computation with the module.
Parameters
----------
data_shapes : list of (str, tuple)
Typically is `data_iter.provide_data`.
label_shapes : list of (str, tuple)
Typically is `data_iter.provide_label`.
for_training : bool
Default is `True`. Whether the executors should be bind for training.
inputs_need_grad : bool
Default is `False`. Whether the gradients to the input data need to be computed.
Typically this is not needed. But this might be needed when implementing composition
of modules.
force_rebind : bool
Default is `False`. This function does nothing if the executors are already
binded. But with this `True`, the executors will be forced to rebind.
shared_module : Module
Default is `None`. This is used in bucketing. When not `None`, the shared module
essentially corresponds to a different bucket -- a module with different symbol
but with the same sets of parameters (e.g. unrolled RNNs with different lengths).
"""
# force rebinding is typically used when one want to switch from
# training to prediction phase.
if force_rebind:
self._reset_bind()
if self.binded:
self.logger.warning('Already binded, ignoring bind()')
return
self.for_training = for_training
self.inputs_need_grad = inputs_need_grad
self.binded = True
self._grad_req = grad_req
if not for_training:
assert not inputs_need_grad
else:
pass
# this is not True, as some module might not contains a loss function
# that consumes the labels
# assert label_shapes is not None
# self._data_shapes, self._label_shapes = _parse_data_desc(
# self.data_names, self.label_names, data_shapes, label_shapes)
self._data_shapes, self._label_shapes = zip(*[_parse_data_desc(self.data_names, self.label_names, data_shape, label_shape)
for data_shape, label_shape in zip(data_shapes, label_shapes)])
if self._label_shapes.count(None) == len(self._label_shapes):
self._label_shapes = None
if shared_module is not None:
assert isinstance(shared_module, Module) and \
shared_module.binded and shared_module.params_initialized
shared_group = shared_module._exec_group
else:
shared_group = None
self._exec_group = DataParallelExecutorGroup(self._symbol, self._context,
self._work_load_list, self._data_shapes,
self._label_shapes, self._param_names,
for_training, inputs_need_grad,
shared_group, logger=self.logger,
fixed_param_names=self._fixed_param_names,
grad_req=grad_req,
state_names=self._state_names)
# self._total_exec_bytes = self._exec_group._total_exec_bytes
if shared_module is not None:
self.params_initialized = True
self._arg_params = shared_module._arg_params
self._aux_params = shared_module._aux_params
elif self.params_initialized:
# if the parameters are already initialized, we are re-binding
# so automatically copy the already initialized params
self._exec_group.set_params(self._arg_params, self._aux_params)
else:
assert self._arg_params is None and self._aux_params is None
param_arrays = [
nd.zeros(x[0].shape, dtype=x[0].dtype)
for x in self._exec_group.param_arrays
]
self._arg_params = {name:arr for name, arr in zip(self._param_names, param_arrays)}
aux_arrays = [
nd.zeros(x[0].shape, dtype=x[0].dtype)
for x in self._exec_group.aux_arrays
]
self._aux_params = {name:arr for name, arr in zip(self._aux_names, aux_arrays)}
if shared_module is not None and shared_module.optimizer_initialized:
self.borrow_optimizer(shared_module)
def reshape(self, data_shapes, label_shapes=None):
"""Reshape the module for new input shapes.
Parameters
----------
data_shapes : list of (str, tuple)
Typically is `data_iter.provide_data`.
label_shapes : list of (str, tuple)
Typically is `data_iter.provide_label`.
"""
assert self.binded
# self._data_shapes, self._label_shapes = _parse_data_desc(
# self.data_names, self.label_names, data_shapes, label_shapes)
self._data_shapes, self._label_shapes = zip(*[_parse_data_desc(self.data_names, self.label_names, data_shape, label_shape)
for data_shape, label_shape in zip(data_shapes, label_shapes)])
self._exec_group.reshape(self._data_shapes, self._label_shapes)
def init_optimizer(self, kvstore='local', optimizer='sgd',
optimizer_params=(('learning_rate', 0.01),), force_init=False):
"""Install and initialize optimizers.
Parameters
----------
kvstore : str or KVStore
Default `'local'`.
optimizer : str or Optimizer
Default `'sgd'`
optimizer_params : dict
Default `(('learning_rate', 0.01),)`. The default value is not a dictionary,
just to avoid pylint warning of dangerous default values.
force_init : bool
Default `False`, indicating whether we should force re-initializing the
optimizer in the case an optimizer is already installed.
"""
assert self.binded and self.params_initialized
if self.optimizer_initialized and not force_init:
self.logger.warning('optimizer already initialized, ignoring...')
return
(kvstore, update_on_kvstore) = \
_create_kvstore(kvstore, len(self._context), self._arg_params)
batch_size = self._exec_group.batch_size
if kvstore and 'dist' in kvstore.type and '_sync' in kvstore.type:
batch_size *= kvstore.num_workers
rescale_grad = 1.0/batch_size
if isinstance(optimizer, str):
idx2name = {}
if update_on_kvstore:
idx2name.update(enumerate(self._exec_group.param_names))
else:
for k in range(len(self._context)):
idx2name.update({i*len(self._context)+k: n
for i, n in enumerate(self._exec_group.param_names)})
optimizer_params = dict(optimizer_params)
if 'rescale_grad' not in optimizer_params:
optimizer_params['rescale_grad'] = rescale_grad
optimizer = opt.create(optimizer,
sym=self.symbol, param_idx2name=idx2name,
**optimizer_params)
else:
assert isinstance(optimizer, opt.Optimizer)
if optimizer.rescale_grad != rescale_grad:
#pylint: disable=no-member
warnings.warn(
"Optimizer created manually outside Module but rescale_grad " +
"is not normalized to 1.0/batch_size/num_workers (%s vs. %s). "%(
optimizer.rescale_grad, rescale_grad) +
"Is this intended?", stacklevel=2)
self._optimizer = optimizer
self._kvstore = kvstore
self._update_on_kvstore = update_on_kvstore
self._updater = None
if kvstore:
# copy initialized local parameters to kvstore
_initialize_kvstore(kvstore=kvstore,
param_arrays=self._exec_group.param_arrays,
arg_params=self._arg_params,
param_names=self._param_names,
update_on_kvstore=update_on_kvstore)
if update_on_kvstore:
kvstore.set_optimizer(self._optimizer)
else:
self._updater = opt.get_updater(optimizer)
self.optimizer_initialized = True
if self._preload_opt_states is not None:
self.load_optimizer_states(self._preload_opt_states)
self._preload_opt_states = None
def borrow_optimizer(self, shared_module):
"""Borrow optimizer from a shared module. Used in bucketing, where exactly the same
optimizer (esp. kvstore) is used.
Parameters
----------
shared_module : Module
"""
assert shared_module.optimizer_initialized
self._optimizer = shared_module._optimizer
self._kvstore = shared_module._kvstore
self._update_on_kvstore = shared_module._update_on_kvstore
self._updater = shared_module._updater
self.optimizer_initialized = True
def forward(self, data_batch, is_train=None):
"""Forward computation.
Parameters
----------
data_batch : DataBatch
Could be anything with similar API implemented.
is_train : bool
Default is `None`, which means `is_train` takes the value of `self.for_training`.
"""
assert self.binded and self.params_initialized
self._exec_group.forward(data_batch, is_train)
def backward(self, out_grads=None):
"""Backward computation.
Parameters
----------
out_grads : NDArray or list of NDArray, optional
Gradient on the outputs to be propagated back.
This parameter is only needed when bind is called
on outputs that are not a loss function.
"""
assert self.binded and self.params_initialized
self._exec_group.backward(out_grads=out_grads)
def update(self):
"""Update parameters according to the installed optimizer and the gradients computed
in the previous forward-backward batch.
"""
assert self.binded and self.params_initialized and self.optimizer_initialized
self._params_dirty = True
if self._update_on_kvstore:
_update_params_on_kvstore(self._exec_group.param_arrays,
self._exec_group.grad_arrays,
self._kvstore)
else:
_update_params(self._exec_group.param_arrays,
self._exec_group.grad_arrays,
updater=self._updater,
num_device=len(self._context),
kvstore=self._kvstore)
def get_outputs(self, merge_multi_context=True):
"""Get outputs of the previous forward computation.
Parameters
----------
merge_multi_context : bool
Default is `True`. In the case when data-parallelism is used, the outputs
will be collected from multiple devices. A `True` value indicate that we
should merge the collected results so that they look like from a single
executor.
Returns
-------
If `merge_multi_context` is `True`, it is like `[out1, out2]`. Otherwise, it
is like `[[out1_dev1, out1_dev2], [out2_dev1, out2_dev2]]`. All the output
elements are `NDArray`.
"""
assert self.binded and self.params_initialized
return self._exec_group.get_outputs(merge_multi_context=merge_multi_context)
def get_input_grads(self, merge_multi_context=True):
"""Get the gradients with respect to the inputs of the module.
Parameters
----------
merge_multi_context : bool
Default is `True`. In the case when data-parallelism is used, the outputs
will be collected from multiple devices. A `True` value indicate that we
should merge the collected results so that they look like from a single
executor.
Returns
-------
If `merge_multi_context` is `True`, it is like `[grad1, grad2]`. Otherwise, it
is like `[[grad1_dev1, grad1_dev2], [grad2_dev1, grad2_dev2]]`. All the output
elements are `NDArray`.
"""
assert self.binded and self.params_initialized and self.inputs_need_grad
return self._exec_group.get_input_grads(merge_multi_context=merge_multi_context)
def get_states(self, merge_multi_context=True):
"""Get states from all devices
Parameters
----------
merge_multi_context : bool
Default is `True`. In the case when data-parallelism is used, the states
will be collected from multiple devices. A `True` value indicate that we
should merge the collected results so that they look like from a single
executor.
Returns
-------
If `merge_multi_context` is `True`, it is like `[out1, out2]`. Otherwise, it
is like `[[out1_dev1, out1_dev2], [out2_dev1, out2_dev2]]`. All the output
elements are `NDArray`.
"""
assert self.binded and self.params_initialized
return self._exec_group.get_states(merge_multi_context=merge_multi_context)
def set_states(self, states=None, value=None):
"""Set value for states. Only one of states & value can be specified.
Parameters
----------
states : list of list of NDArrays
source states arrays formatted like [[state1_dev1, state1_dev2],
[state2_dev1, state2_dev2]].
value : number
a single scalar value for all state arrays.
"""
assert self.binded and self.params_initialized
self._exec_group.set_states(states, value)
def update_metric(self, eval_metric, labels):
"""Evaluate and accumulate evaluation metric on outputs of the last forward computation.
Parameters
----------
eval_metric : EvalMetric
labels : list of NDArray
Typically `data_batch.label`.
"""
self._exec_group.update_metric(eval_metric, labels)
def _sync_params_from_devices(self):
"""Synchronize parameters from devices to CPU. This function should be called after
calling `update` that updates the parameters on the devices, before one can read the
latest parameters from `self._arg_params` and `self._aux_params`.
"""
self._exec_group.get_params(self._arg_params, self._aux_params)
self._params_dirty = False
def save_optimizer_states(self, fname):
"""Save optimizer (updater) state to file
Parameters
----------
fname : str
Path to output states file.
"""
assert self.optimizer_initialized
if self._update_on_kvstore:
self._kvstore.save_optimizer_states(fname)
else:
with open(fname, 'wb') as fout:
fout.write(self._updater.get_states())
def load_optimizer_states(self, fname):
"""Load optimizer (updater) state from file
Parameters
----------
fname : str
Path to input states file.
"""
assert self.optimizer_initialized
if self._update_on_kvstore:
self._kvstore.load_optimizer_states(fname)
else:
self._updater.set_states(open(fname, 'rb').read())
def install_monitor(self, mon):
""" Install monitor on all executors """
assert self.binded
self._exec_group.install_monitor(mon)
class MutableModule(BaseModule):
"""A mutable module is a module that supports variable input data.
Parameters
----------
symbol : Symbol
data_names : list of str
label_names : list of str
logger : Logger
context : Context or list of Context
work_load_list : list of number
max_data_shapes : list of (name, shape) tuple, designating inputs whose shape vary
max_label_shapes : list of (name, shape) tuple, designating inputs whose shape vary
fixed_param_prefix : list of str, indicating fixed parameters
"""
def __init__(self, symbol, data_names, label_names,
logger=logging, context=ctx.cpu(), work_load_list=None,
max_data_shapes=None, max_label_shapes=None, fixed_param_prefix=None):
super(MutableModule, self).__init__(logger=logger)
self._symbol = symbol
self._data_names = data_names
self._label_names = label_names
self._context = context
self._work_load_list = work_load_list
self._curr_module = None
self._max_data_shapes = max_data_shapes
self._max_label_shapes = max_label_shapes
self._fixed_param_prefix = fixed_param_prefix
fixed_param_names = list()
if fixed_param_prefix is not None:
for name in self._symbol.list_arguments():
for prefix in self._fixed_param_prefix:
if prefix in name:
fixed_param_names.append(name)
self._fixed_param_names = fixed_param_names
self._preload_opt_states = None
def _reset_bind(self):
self.binded = False
self._curr_module = None
@property
def data_names(self):
return self._data_names
@property
def output_names(self):
return self._symbol.list_outputs()
@property
def data_shapes(self):
assert self.binded
return self._curr_module.data_shapes
@property
def label_shapes(self):
assert self.binded
return self._curr_module.label_shapes
@property
def output_shapes(self):
assert self.binded
return self._curr_module.output_shapes
def get_params(self):
assert self.binded and self.params_initialized
return self._curr_module.get_params()
def init_params(self, initializer=Uniform(0.01), arg_params=None, aux_params=None,
allow_missing=False, force_init=False):
if self.params_initialized and not force_init:
return
assert self.binded, 'call bind before initializing the parameters'
self._curr_module.init_params(initializer=initializer, arg_params=arg_params,
aux_params=aux_params, allow_missing=allow_missing,
force_init=force_init)
self.params_initialized = True
def bind(self, data_shapes, label_shapes=None, for_training=True,
inputs_need_grad=False, force_rebind=False, shared_module=None, grad_req='write'):
# in case we already initialized params, keep it
if self.params_initialized:
arg_params, aux_params = self.get_params()
# force rebinding is typically used when one want to switch from
# training to prediction phase.
if force_rebind:
self._reset_bind()
if self.binded:
self.logger.warning('Already binded, ignoring bind()')
return
assert shared_module is None, 'shared_module for MutableModule is not supported'
self.for_training = for_training
self.inputs_need_grad = inputs_need_grad
self.binded = True
max_shapes_dict = dict()
if self._max_data_shapes is not None:
max_shapes_dict.update(dict(self._max_data_shapes[0]))
if self._max_label_shapes is not None:
max_shapes_dict.update(dict(self._max_label_shapes[0]))
max_data_shapes = list()
for name, shape in data_shapes[0]:
if name in max_shapes_dict:
max_data_shapes.append((name, max_shapes_dict[name]))
else:
max_data_shapes.append((name, shape))
max_label_shapes = list()
if not label_shapes.count(None) == len(label_shapes):
for name, shape in label_shapes[0]:
if name in max_shapes_dict:
max_label_shapes.append((name, max_shapes_dict[name]))
else:
max_label_shapes.append((name, shape))
if len(max_label_shapes) == 0:
max_label_shapes = None
module = Module(self._symbol, self._data_names, self._label_names, logger=self.logger,
context=self._context, work_load_list=self._work_load_list,
fixed_param_names=self._fixed_param_names)
module.bind([max_data_shapes for _ in xrange(len(self._context))], [max_label_shapes for _ in xrange(len(self._context))],
for_training, inputs_need_grad, force_rebind=False, shared_module=None)
self._curr_module = module
# copy back saved params, if already initialized
if self.params_initialized:
self.set_params(arg_params, aux_params)
def save_checkpoint(self, prefix, epoch, save_optimizer_states=False):
"""Save current progress to checkpoint.
Use mx.callback.module_checkpoint as epoch_end_callback to save during training.
Parameters
----------
prefix : str
The file prefix to checkpoint to
epoch : int
The current epoch number
save_optimizer_states : bool
Whether to save optimizer states for continue training
"""
self._curr_module.save_checkpoint(prefix, epoch, save_optimizer_states)
def init_optimizer(self, kvstore='local', optimizer='sgd',
optimizer_params=(('learning_rate', 0.01),), force_init=False):
assert self.binded and self.params_initialized
if self.optimizer_initialized and not force_init:
self.logger.warning('optimizer already initialized, ignoring.')
return
self._curr_module._preload_opt_states = self._preload_opt_states
self._curr_module.init_optimizer(kvstore, optimizer, optimizer_params,
force_init=force_init)
self.optimizer_initialized = True
def fit(self, train_data, eval_data=None, eval_metric='acc',
epoch_end_callback=None, batch_end_callback=None, kvstore='local',
optimizer='sgd', optimizer_params=(('learning_rate', 0.01),),
eval_end_callback=None,
eval_batch_end_callback=None, initializer=Uniform(0.01),
arg_params=None, aux_params=None, allow_missing=False,
force_rebind=False, force_init=False, begin_epoch=0, num_epoch=None,
validation_metric=None, monitor=None, prefix=None):
"""Train the module parameters.
Parameters
----------
train_data : DataIter
eval_data : DataIter
If not `None`, will be used as validation set and evaluate the performance
after each epoch.
eval_metric : str or EvalMetric
Default `'acc'`. The performance measure used to display during training.
epoch_end_callback : function or list of function
Each callback will be called with the current `epoch`, `symbol`, `arg_params`
and `aux_params`.
batch_end_callback : function or list of function
Each callback will be called with a `BatchEndParam`.
kvstore : str or KVStore
Default `'local'`.
optimizer : str or Optimizer
Default `'sgd'`
optimizer_params : dict
Default `(('learning_rate', 0.01),)`. The parameters for the optimizer constructor.
The default value is not a `dict`, just to avoid pylint warning on dangerous
default values.
eval_end_callback : function or list of function
These will be called at the end of each full evaluation, with the metrics over
the entire evaluation set.
eval_batch_end_callback : function or list of function
These will be called at the end of each minibatch during evaluation
initializer : Initializer
Will be called to initialize the module parameters if not already initialized.
arg_params : dict
Default `None`, if not `None`, should be existing parameters from a trained
model or loaded from a checkpoint (previously saved model). In this case,
the value here will be used to initialize the module parameters, unless they
are already initialized by the user via a call to `init_params` or `fit`.
`arg_params` has higher priority to `initializer`.
aux_params : dict
Default `None`. Similar to `arg_params`, except for auxiliary states.
allow_missing : bool
Default `False`. Indicate whether we allow missing parameters when `arg_params`
and `aux_params` are not `None`. If this is `True`, then the missing parameters
will be initialized via the `initializer`.
force_rebind : bool
Default `False`. Whether to force rebinding the executors if already binded.
force_init : bool
Default `False`. Indicate whether we should force initialization even if the
parameters are already initialized.
begin_epoch : int
Default `0`. Indicate the starting epoch. Usually, if we are resuming from a
checkpoint saved at a previous training phase at epoch N, then we should specify
this value as N+1.
num_epoch : int
Number of epochs to run training.
Examples
--------
An example of using fit for training::
>>> #Assume training dataIter and validation dataIter are ready
>>> mod.fit(train_data=train_dataiter, eval_data=val_dataiter,
optimizer_params={'learning_rate':0.01, 'momentum': 0.9},
num_epoch=10)
"""
assert num_epoch is not None, 'please specify number of epochs'
self.bind(data_shapes=train_data.provide_data, label_shapes=train_data.provide_label,
for_training=True, force_rebind=force_rebind)
if monitor is not None:
self.install_monitor(monitor)
self.init_params(initializer=initializer, arg_params=arg_params, aux_params=aux_params,
allow_missing=allow_missing, force_init=force_init)
self.init_optimizer(kvstore=kvstore, optimizer=optimizer,
optimizer_params=optimizer_params)
if validation_metric is None:
validation_metric = eval_metric
if not isinstance(eval_metric, metric.EvalMetric):
eval_metric = metric.create(eval_metric)
################################################################################
# training loop
################################################################################
for epoch in range(begin_epoch, num_epoch):
tic = time.time()
eval_metric.reset()
for nbatch, data_batch in enumerate(train_data):
if monitor is not None:
monitor.tic()
self.forward_backward(data_batch)
self.update()
self.update_metric(eval_metric, data_batch.label)
if monitor is not None:
monitor.toc_print()
if batch_end_callback is not None:
batch_end_params = BatchEndParam(epoch=epoch, nbatch=nbatch,
eval_metric=eval_metric,
locals=locals())
for callback in _as_list(batch_end_callback):
callback(batch_end_params)
# one epoch of training is finished
for name, val in eval_metric.get_name_value():
self.logger.info('Epoch[%d] Train-%s=%f', epoch, name, val)
toc = time.time()
self.logger.info('Epoch[%d] Time cost=%.3f', epoch, (toc-tic))
# sync aux params across devices
arg_params, aux_params = self.get_params()
self.set_params(arg_params, aux_params)
if epoch_end_callback is not None:
for callback in _as_list(epoch_end_callback):
callback(epoch, self.symbol, arg_params, aux_params)
#----------------------------------------
# evaluation on validation set
if eval_data:
res = self.score(eval_data, validation_metric,
score_end_callback=eval_end_callback,