scan_function() - Code Metrics - mila-udem/blocks - Measure and Improve Code Quality continuously with Scrutinizer

scan_function() A
last analyzed 2017-06-06 01:33 UTC

↳ Parent: recurrent_apply()

Complexity

Conditions

Size

Total Lines

Duplication

Lines	0
Ratio	0 %

Importance

Changes	1
Bugs	0	Features	0

Metric	Value
cc	3
c	1
b	0
f	0
dl	0
loc	15
rs	9.4285

# -*- coding: utf-8 -*-
import inspect
import logging
from six import wraps


from picklable_itertools.extras import equizip
import theano
from theano import tensor, Variable

from ..base import Application, application, Brick
from ...initialization import NdarrayInitialization
from ...utils import pack, dict_union, dict_subset, is_shared_variable

logger = logging.getLogger(__name__)

unknown_scan_input = """


Your function uses a non-shared variable other than those given \
by scan explicitly. That can significantly slow down `tensor.grad` \
call. Did you forget to declare it in `contexts`?"""


class BaseRecurrent(Brick):
    """Base class for brick with recurrent application method."""
    has_bias = False

    @application
    def initial_states(self, batch_size, *args, **kwargs):

        r"""Return initial states for an application call.

        Default implementation assumes that the recurrent application
        method is called `apply`. It fetches the state names
        from `apply.states` and a returns a zero matrix for each of them.

        :class:`SimpleRecurrent`, :class:`LSTM` and :class:`GatedRecurrent`
        override this method  with trainable initial states initialized
        with zeros.

        Parameters
        ----------
        batch_size : int
            The batch size.
        \*args
            The positional arguments of the application call.
        \*\*kwargs
            The keyword arguments of the application call.

        """
        result = []
        for state in self.apply.states:

            dim = self.get_dim(state)
            if dim == 0:
                result.append(tensor.zeros((batch_size,)))
            else:
                result.append(tensor.zeros((batch_size, dim)))
        return result

    @initial_states.property('outputs')
    def initial_states_outputs(self):
        return self.apply.states



def recurrent(*args, **kwargs):
    """Wraps an apply method to allow its iterative application.

    This decorator allows you to implement only one step of a recurrent
    network and enjoy applying it to sequences for free. The idea behind is
    that its most general form information flow of an RNN can be described
    as follows: depending on the context and driven by input sequences the
    RNN updates its states and produces output sequences.

    Given a method describing one step of an RNN and a specification
    which of its inputs are the elements of the input sequence,
    which are the states and which are the contexts, this decorator
    returns an application method which implements the whole RNN loop.
    The returned application method also has additional parameters,
    see documentation of the `recurrent_apply` inner function below.

    Parameters
    ----------
    sequences : list of strs
        Specifies which of the arguments are elements of input sequences.
    states : list of strs
        Specifies which of the arguments are the states.
    contexts : list of strs
        Specifies which of the arguments are the contexts.
    outputs : list of strs
        Names of the outputs. The outputs whose names match with those
        in the `state` parameter are interpreted as next step states.

    Returns
    -------
    recurrent_apply : :class:`~blocks.bricks.base.Application`
        The new application method that applies the RNN to sequences.

    See Also
    --------
    :doc:`The tutorial on RNNs </rnn>`

    """
    def recurrent_wrapper(application_function):
        arg_spec = inspect.getargspec(application_function)
        arg_names = arg_spec.args[1:]

        @wraps(application_function)
        def recurrent_apply(brick, application, application_call,
param = 5

class Foo:
    def __init__(self, param):   # "param" would be flagged here
        self.param = param
                            *args, **kwargs):
            """Iterates a transition function.

            Parameters
            ----------
            iterate : bool
                If ``True`` iteration is made. By default ``True``.
            reverse : bool
                If ``True``, the sequences are processed in backward
                direction. ``False`` by default.
            return_initial_states : bool
                If ``True``, initial states are included in the returned
                state tensors. ``False`` by default.

            """
            # Extract arguments related to iteration and immediately relay the
            # call to the wrapped function if `iterate=False`
            iterate = kwargs.pop('iterate', True)
            if not iterate:
                return application_function(brick, *args, **kwargs)
            reverse = kwargs.pop('reverse', False)
            scan_kwargs = kwargs.pop('scan_kwargs', {})
            return_initial_states = kwargs.pop('return_initial_states', False)

            # Push everything to kwargs
            for arg, arg_name in zip(args, arg_names):
                kwargs[arg_name] = arg

            # Make sure that all arguments for scan are tensor variables
            scan_arguments = (application.sequences + application.states +
                              application.contexts)
            for arg in scan_arguments:
                if arg in kwargs:
                    if kwargs[arg] is None:
                        del kwargs[arg]
                    else:
                        kwargs[arg] = tensor.as_tensor_variable(kwargs[arg])

            # Check which sequence and contexts were provided
            sequences_given = dict_subset(kwargs, application.sequences,
                                          must_have=False)
            contexts_given = dict_subset(kwargs, application.contexts,
                                         must_have=False)

            # Determine number of steps and batch size.
            if len(sequences_given):
                # TODO Assumes 1 time dim!
                shape = list(sequences_given.values())[0].shape
                n_steps = shape[0]
                batch_size = shape[1]
            else:
                # TODO Raise error if n_steps and batch_size not found?
                n_steps = kwargs.pop('n_steps')
                batch_size = kwargs.pop('batch_size')

            # Handle the rest kwargs
            rest_kwargs = {key: value for key, value in kwargs.items()
                           if key not in scan_arguments}
            for value in rest_kwargs.values():
                if (isinstance(value, Variable) and not
                        is_shared_variable(value)):
                    logger.warning("unknown input {}".format(value) +
                                   unknown_scan_input)

            # Ensure that all initial states are available.
            initial_states = brick.initial_states(batch_size, as_dict=True,
                                                  *args, **kwargs)
            for state_name in application.states:
                dim = brick.get_dim(state_name)
                if state_name in kwargs:
                    if isinstance(kwargs[state_name], NdarrayInitialization):
                        kwargs[state_name] = tensor.alloc(
                            kwargs[state_name].generate(brick.rng, (1, dim)),
                            batch_size, dim)
                    elif isinstance(kwargs[state_name], Application):
                        kwargs[state_name] = (
                            kwargs[state_name](state_name, batch_size,
                                               *args, **kwargs))
                else:
                    try:
                        kwargs[state_name] = initial_states[state_name]
                    except KeyError:
                        raise KeyError(
                            "no initial state for '{}' of the brick {}".format(
                                state_name, brick.name))
            states_given = dict_subset(kwargs, application.states)

            # Theano issue 1772
            for name, state in states_given.items():
                states_given[name] = tensor.unbroadcast(state,
                                                        *range(state.ndim))

            def scan_function(*args):
                args = list(args)
                arg_names = (list(sequences_given) +
                             [output for output in application.outputs
                              if output in application.states] +
                             list(contexts_given))
                kwargs = dict(equizip(arg_names, args))
                kwargs.update(rest_kwargs)
                outputs = application(iterate=False, **kwargs)
                # We want to save the computation graph returned by the
                # `application_function` when it is called inside the
                # `theano.scan`.
                application_call.inner_inputs = args
                application_call.inner_outputs = pack(outputs)
                return outputs
            outputs_info = [
                states_given[name] if name in application.states
                else None
                for name in application.outputs]
            result, updates = theano.scan(
                scan_function, sequences=list(sequences_given.values()),
                outputs_info=outputs_info,
                non_sequences=list(contexts_given.values()),
                n_steps=n_steps,
                go_backwards=reverse,
                name='{}_{}_scan'.format(
                    brick.name, application.application_name),
                **scan_kwargs)
            result = pack(result)
            if return_initial_states:
                # Undo Subtensor
                for i, info in enumerate(outputs_info):
                    if info is not None:
                        assert isinstance(result[i].owner.op,
                                          tensor.subtensor.Subtensor)
                        result[i] = result[i].owner.inputs[0]
            if updates:
                application_call.updates = dict_union(application_call.updates,
                                                      updates)

            return result

        return recurrent_apply

    # Decorator can be used with or without arguments
    assert (args and not kwargs) or (not args and kwargs)
    if args:
        application_function, = args
        return application(recurrent_wrapper(application_function))
    else:
        def wrap_application(application_function):
            return application(**kwargs)(
                recurrent_wrapper(application_function))
        return wrap_application


1			# -- coding: utf-8 --
2			import inspect
3			import logging
4			from six import wraps
			0 ignored issues – show Bug introduced 2016-06-01 21:48 UTC by Report Bug Copy Issue Report The name `wraps` does not seem to exist in module `six`. Loading history...
5
6			from picklable_itertools.extras import equizip
7			import theano
8			from theano import tensor, Variable
9
10			from ..base import Application, application, Brick
11			from ...initialization import NdarrayInitialization
12			from ...utils import pack, dict_union, dict_subset, is_shared_variable
13
14			logger = logging.getLogger(__name__)
15
16			unknown_scan_input = """
			0 ignored issues – show Coding Style Naming introduced 2016-06-01 21:48 UTC by Report Bug Copy Issue Report The name `unknown_scan_input` does not conform to the constant naming conventions (`(([A-Z_][A-Z0-9_])\|(__.__))$`). This check looks for invalid names for a range of different identifiers. You can set regular expressions to which the identifiers must conform if the defaults do not match your requirements. If your project includes a Pylint configuration file, the settings contained in that file take precedence. To find out more about Pylint, please refer to their site. Loading history...
17
18			Your function uses a non-shared variable other than those given \
19			by scan explicitly. That can significantly slow down `tensor.grad` \
20			call. Did you forget to declare it in `contexts`?"""
21
22
23			class BaseRecurrent(Brick):
24			"""Base class for brick with recurrent application method."""
25			has_bias = False
26
27			@application
28			def initial_states(self, batch_size, args, *kwargs):
			0 ignored issues – show Unused Code introduced 2016-06-01 21:48 UTC by Report Bug Copy Issue Report The argument `args` seems to be unused. Loading history... Unused Code introduced 2016-06-01 21:48 UTC by Report Bug Copy Issue Report The argument `kwargs` seems to be unused. Loading history...
29			r"""Return initial states for an application call.
30
31			Default implementation assumes that the recurrent application
32			method is called `apply`. It fetches the state names
33			from `apply.states` and a returns a zero matrix for each of them.
34
35			:class:`SimpleRecurrent`, :class:`LSTM` and :class:`GatedRecurrent`
36			override this method with trainable initial states initialized
37			with zeros.
38
39			Parameters
40			----------
41			batch_size : int
42			The batch size.
43			\*args
44			The positional arguments of the application call.
45			\\kwargs
46			The keyword arguments of the application call.
47
48			"""
49			result = []
50			for state in self.apply.states:
			0 ignored issues – show Bug introduced 2015-11-24 17:27 UTC by Report Bug Copy Issue Report The Instance of `BaseRecurrent` does not seem to have a member named `apply`. This check looks for calls to members that are non-existent. These calls will fail. The member could have been renamed or removed. Loading history...
51			dim = self.get_dim(state)
52			if dim == 0:
53			result.append(tensor.zeros((batch_size,)))
54			else:
55			result.append(tensor.zeros((batch_size, dim)))
56			return result
57
58			@initial_states.property('outputs')
59			def initial_states_outputs(self):
60			return self.apply.states
			0 ignored issues – show Bug introduced 2016-06-01 21:48 UTC by Report Bug Copy Issue Report The Instance of `BaseRecurrent` does not seem to have a member named `apply`. This check looks for calls to members that are non-existent. These calls will fail. The member could have been renamed or removed. Loading history...
61
62
63			def recurrent(args, *kwargs):
64			"""Wraps an apply method to allow its iterative application.
65
66			This decorator allows you to implement only one step of a recurrent
67			network and enjoy applying it to sequences for free. The idea behind is
68			that its most general form information flow of an RNN can be described
69			as follows: depending on the context and driven by input sequences the
70			RNN updates its states and produces output sequences.
71
72			Given a method describing one step of an RNN and a specification
73			which of its inputs are the elements of the input sequence,
74			which are the states and which are the contexts, this decorator
75			returns an application method which implements the whole RNN loop.
76			The returned application method also has additional parameters,
77			see documentation of the `recurrent_apply` inner function below.
78
79			Parameters
80			----------
81			sequences : list of strs
82			Specifies which of the arguments are elements of input sequences.
83			states : list of strs
84			Specifies which of the arguments are the states.
85			contexts : list of strs
86			Specifies which of the arguments are the contexts.
87			outputs : list of strs
88			Names of the outputs. The outputs whose names match with those
89			in the `state` parameter are interpreted as next step states.
90
91			Returns
92			-------
93			recurrent_apply : :class:`~blocks.bricks.base.Application`
94			The new application method that applies the RNN to sequences.
95
96			See Also
97			--------
98			:doc:`The tutorial on RNNs </rnn>`
99
100			"""
101			def recurrent_wrapper(application_function):
102			arg_spec = inspect.getargspec(application_function)
103			arg_names = arg_spec.args[1:]
104
105			@wraps(application_function)
106			def recurrent_apply(brick, application, application_call,
			0 ignored issues – show Comprehensibility Bug introduced 2016-06-01 21:48 UTC by Report Bug Copy Issue Report `application` is re-defining a name which is already available in the outer-scope (previously defined on line `10`). It is generally a bad practice to shadow variables from the outer-scope. In most cases, this is done unintentionally and might lead to unexpected behavior: param = 5 class Foo: def __init__(self, param): # "param" would be flagged here self.param = param Loading history...
107			args, *kwargs):
108			"""Iterates a transition function.
109
110			Parameters
111			----------
112			iterate : bool
113			If ``True`` iteration is made. By default ``True``.
114			reverse : bool
115			If ``True``, the sequences are processed in backward
116			direction. ``False`` by default.
117			return_initial_states : bool
118			If ``True``, initial states are included in the returned
119			state tensors. ``False`` by default.
120
121			"""
122			# Extract arguments related to iteration and immediately relay the
123			# call to the wrapped function if `iterate=False`
124			iterate = kwargs.pop('iterate', True)
125			if not iterate:
126			return application_function(brick, args, *kwargs)
127			reverse = kwargs.pop('reverse', False)
128			scan_kwargs = kwargs.pop('scan_kwargs', {})
129			return_initial_states = kwargs.pop('return_initial_states', False)
130
131			# Push everything to kwargs
132			for arg, arg_name in zip(args, arg_names):
133			kwargs[arg_name] = arg
134
135			# Make sure that all arguments for scan are tensor variables
136			scan_arguments = (application.sequences + application.states +
137			application.contexts)
138			for arg in scan_arguments:
139			if arg in kwargs:
140			if kwargs[arg] is None:
141			del kwargs[arg]
142			else:
143			kwargs[arg] = tensor.as_tensor_variable(kwargs[arg])
144
145			# Check which sequence and contexts were provided
146			sequences_given = dict_subset(kwargs, application.sequences,
147			must_have=False)
148			contexts_given = dict_subset(kwargs, application.contexts,
149			must_have=False)
150
151			# Determine number of steps and batch size.
152			if len(sequences_given):
153			# TODO Assumes 1 time dim!
154			shape = list(sequences_given.values())[0].shape
155			n_steps = shape[0]
156			batch_size = shape[1]
157			else:
158			# TODO Raise error if n_steps and batch_size not found?
159			n_steps = kwargs.pop('n_steps')
160			batch_size = kwargs.pop('batch_size')
161
162			# Handle the rest kwargs
163			rest_kwargs = {key: value for key, value in kwargs.items()
164			if key not in scan_arguments}
165			for value in rest_kwargs.values():
166			if (isinstance(value, Variable) and not
167			is_shared_variable(value)):
168			logger.warning("unknown input {}".format(value) +
169			unknown_scan_input)
170
171			# Ensure that all initial states are available.
172			initial_states = brick.initial_states(batch_size, as_dict=True,
173			args, *kwargs)
174			for state_name in application.states:
175			dim = brick.get_dim(state_name)
176			if state_name in kwargs:
177			if isinstance(kwargs[state_name], NdarrayInitialization):
178			kwargs[state_name] = tensor.alloc(
179			kwargs[state_name].generate(brick.rng, (1, dim)),
180			batch_size, dim)
181			elif isinstance(kwargs[state_name], Application):
182			kwargs[state_name] = (
183			kwargs[state_name](state_name, batch_size,
184			args, *kwargs))
185			else:
186			try:
187			kwargs[state_name] = initial_states[state_name]
188			except KeyError:
189			raise KeyError(
190			"no initial state for '{}' of the brick {}".format(
191			state_name, brick.name))
192			states_given = dict_subset(kwargs, application.states)
193
194			# Theano issue 1772
195			for name, state in states_given.items():
196			states_given[name] = tensor.unbroadcast(state,
197			*range(state.ndim))
198
199			def scan_function(*args):
200			args = list(args)
201			arg_names = (list(sequences_given) +
202			[output for output in application.outputs
203			if output in application.states] +
204			list(contexts_given))
205			kwargs = dict(equizip(arg_names, args))
206			kwargs.update(rest_kwargs)
207			outputs = application(iterate=False, **kwargs)
208			# We want to save the computation graph returned by the
209			# `application_function` when it is called inside the
210			# `theano.scan`.
211			application_call.inner_inputs = args
212			application_call.inner_outputs = pack(outputs)
213			return outputs
214			outputs_info = [
215			states_given[name] if name in application.states
216			else None
217			for name in application.outputs]
218			result, updates = theano.scan(
219			scan_function, sequences=list(sequences_given.values()),
220			outputs_info=outputs_info,
221			non_sequences=list(contexts_given.values()),
222			n_steps=n_steps,
223			go_backwards=reverse,
224			name='{}_{}_scan'.format(
225			brick.name, application.application_name),
226			**scan_kwargs)
227			result = pack(result)
228			if return_initial_states:
229			# Undo Subtensor
230			for i, info in enumerate(outputs_info):
231			if info is not None:
232			assert isinstance(result[i].owner.op,
233			tensor.subtensor.Subtensor)
234			result[i] = result[i].owner.inputs[0]
235			if updates:
236			application_call.updates = dict_union(application_call.updates,
237			updates)
238
239			return result
240
241			return recurrent_apply
242
243			# Decorator can be used with or without arguments
244			assert (args and not kwargs) or (not args and kwargs)
245			if args:
246			application_function, = args
247			return application(recurrent_wrapper(application_function))
248			else:
249			def wrap_application(application_function):
250			return application(**kwargs)(
251			recurrent_wrapper(application_function))
252			return wrap_application
253

mila-udem / blocks

scan_function() A last analyzed 2017-06-06 01:33 UTC

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scan_function() A
last analyzed 2017-06-06 01:33 UTC