spaCy/spacy/syntax/parser.pyx
2017-05-04 12:17:59 +02:00

463 lines
16 KiB
Cython

"""
MALT-style dependency parser
"""
# coding: utf-8
# cython: infer_types=True
from __future__ import unicode_literals
from collections import Counter
import ujson
cimport cython
cimport cython.parallel
import numpy.random
from cpython.ref cimport PyObject, Py_INCREF, Py_XDECREF
from cpython.exc cimport PyErr_CheckSignals
from libc.stdint cimport uint32_t, uint64_t
from libc.string cimport memset, memcpy
from libc.stdlib cimport malloc, calloc, free
from thinc.typedefs cimport weight_t, class_t, feat_t, atom_t, hash_t
from thinc.linear.avgtron cimport AveragedPerceptron
from thinc.linalg cimport VecVec
from thinc.structs cimport SparseArrayC, FeatureC, ExampleC
from thinc.extra.eg cimport Example
from cymem.cymem cimport Pool, Address
from murmurhash.mrmr cimport hash64
from preshed.maps cimport MapStruct
from preshed.maps cimport map_get
from . import _parse_features
from ._parse_features cimport CONTEXT_SIZE
from ._parse_features cimport fill_context
from .stateclass cimport StateClass
from ._state cimport StateC
from .nonproj import PseudoProjectivity
from .transition_system import OracleError
from .transition_system cimport TransitionSystem, Transition
from ..structs cimport TokenC
from ..tokens.doc cimport Doc
from ..strings cimport StringStore
from ..gold cimport GoldParse
USE_FTRL = True
DEBUG = False
def set_debug(val):
global DEBUG
DEBUG = val
@layerize
def get_context_tokens(states, drop=0.):
for state in states:
context[i, 0] = state.B(0)
context[i, 1] = state.S(0)
context[i, 2] = state.S(1)
context[i, 3] = state.L(state.S(0), 1)
context[i, 4] = state.L(state.S(0), 2)
context[i, 5] = state.R(state.S(0), 1)
context[i, 6] = state.R(state.S(0), 2)
return (context, states), None
def extract_features(attrs):
def forward(contexts_states, drop=0.):
contexts, states = contexts_states
for i, state in enumerate(states):
for j, tok_i in enumerate(contexts[i]):
token = state.get_token(tok_i)
for k, attr in enumerate(attrs):
output[i, j, k] = getattr(token, attr)
return output, None
return layerize(forward)
def build_tok2vec(lang, width, depth, embed_size):
cols = [LEX_ID, PREFIX, SUFFIX, SHAPE]
static = StaticVectors('en', width, column=cols.index(LEX_ID))
prefix = HashEmbed(width, embed_size, column=cols.index(PREFIX))
suffix = HashEmbed(width, embed_size, column=cols.index(SUFFIX))
shape = HashEmbed(width, embed_size, column=cols.index(SHAPE))
with Model.overload_operaters('>>': chain, '|': concatenate, '+': add):
tok2vec = (
extract_features(cols)
>> (static | prefix | suffix | shape)
>> (ExtractWindow(nW=1) >> Maxout(width)) ** depth
)
return tok2vec
def build_parse2vec(width, embed_size):
cols = [TAG, DEP]
tag_vector = HashEmbed(width, 1000, column=cols.index(TAG))
dep_vector = HashEmbed(width, 1000, column=cols.index(DEP))
with Model.overload_operaters('>>': chain):
model = (
extract_features([TAG, DEP])
>> (tag_vector | dep_vector)
)
return model
def build_model(get_contexts, tok2vec, parse2vec, width, depth, nr_class):
with Model.overload_operaters('>>': chain):
model = (
get_contexts
>> (tok2vec | parse2vec)
>> Maxout(width) ** depth
>> Softmax(nr_class)
)
return model
cdef class Parser:
"""
Base class of the DependencyParser and EntityRecognizer.
"""
@classmethod
def load(cls, path, Vocab vocab, TransitionSystem=None, require=False, **cfg):
"""
Load the statistical model from the supplied path.
Arguments:
path (Path):
The path to load from.
vocab (Vocab):
The vocabulary. Must be shared by the documents to be processed.
require (bool):
Whether to raise an error if the files are not found.
Returns (Parser):
The newly constructed object.
"""
with (path / 'config.json').open() as file_:
cfg = ujson.load(file_)
self = cls(vocab, TransitionSystem=TransitionSystem, model=None, **cfg)
if (path / 'model').exists():
self.model.load(str(path / 'model'))
elif require:
raise IOError(
"Required file %s/model not found when loading" % str(path))
return self
def __init__(self, Vocab vocab, TransitionSystem=None, model=None, **cfg):
"""
Create a Parser.
Arguments:
vocab (Vocab):
The vocabulary object. Must be shared with documents to be processed.
model (thinc Model):
The statistical model.
Returns (Parser):
The newly constructed object.
"""
if TransitionSystem is None:
TransitionSystem = self.TransitionSystem
self.vocab = vocab
cfg['actions'] = TransitionSystem.get_actions(**cfg)
self.moves = TransitionSystem(vocab.strings, cfg['actions'])
if model is None:
model = self.build_model(**cfg)
self.model = model
self.cfg = cfg
def __reduce__(self):
return (Parser, (self.vocab, self.moves, self.model), None, None)
def __call__(self, Doc tokens):
"""
Apply the parser or entity recognizer, setting the annotations onto the Doc object.
Arguments:
doc (Doc): The document to be processed.
Returns:
None
"""
self.parse_batch([tokens])
self.moves.finalize_doc(tokens)
def parse_batch(self, docs):
states = self._init_states(docs)
todo = list(states)
nr_class = self.moves.n_moves
while todo:
scores = self.model.predict(todo)
self._validate_batch(is_valid, scores, states)
for state, guess in zip(todo, scores.argmax(axis=1)):
action = self.moves.c[guess]
action.do(state, action.label)
todo = [state for state in todo if not state.is_final()]
for state, doc in zip(states, docs):
self.moves.finalize_state(state, doc)
def pipe(self, stream, int batch_size=1000, int n_threads=2):
"""
Process a stream of documents.
Arguments:
stream: The sequence of documents to process.
batch_size (int):
The number of documents to accumulate into a working set.
n_threads (int):
The number of threads with which to work on the buffer in parallel.
Yields (Doc): Documents, in order.
"""
cdef Pool mem = Pool()
cdef int* lengths = <int*>mem.alloc(batch_size, sizeof(int))
cdef Doc doc
cdef int i
cdef int nr_feat = self.model.nr_feat
cdef int status
queue = []
for doc in stream:
doc_ptr[len(queue)] = doc.c
lengths[len(queue)] = doc.length
queue.append(doc)
if len(queue) == batch_size:
self.parse_batch(queue)
for doc in queue:
self.moves.finalize_doc(doc)
yield doc
queue = []
if queue:
self.parse_batch(queue)
for doc in queue:
self.moves.finalize_doc(doc)
yield doc
def update(self, docs, golds, drop=0., sgd=None):
if isinstance(docs, Doc) and isinstance(golds, GoldParse):
return self.update([docs], [golds], drop=drop)
states = self._init_states(docs)
nr_class = self.moves.n_moves
while states:
scores, finish_update = self.model.begin_update(states, drop=drop)
self._validate_batch(is_valid, scores, states)
for i, state in enumerate(states):
self.moves.set_costs(costs[i], is_valid, state, golds[i])
self._transition_batch(states, scores)
self._set_gradient(gradients, scores, costs)
finish_update(gradients, sgd=sgd)
gradients.fill(0)
states = [state for state in states if not state.is_final()]
gradients = gradients[:len(states)]
costs = costs[:len(states)]
return 0
def _validate_batch(self, is_valid, scores, states):
for i, state in enumerate(states):
self.moves.set_valid(is_valid, state)
for j in range(self.moves.n_moves):
if not is_valid[j]:
scores[i, j] = 0
def _transition_batch(self, states, scores):
for state, guess in zip(states, scores.argmax(axis=1)):
action = self.moves.c[guess]
action.do(state, action.label)
def _init_states(self, docs):
states = []
cdef Doc doc
for i, doc in enumerate(docs):
state = StateClass.init(doc)
self.moves.initialize_state(state)
return states
def _set_gradient(self, gradients, scores, costs):
"""Do multi-label log loss"""
cdef double Z, gZ, max_, g_max
maxes = scores.max(axis=1)
g_maxes = (scores * costs <= 0).max(axis=1)
exps = (scores-maxes).exp()
g_exps = (g_scores-g_maxes).exp()
Zs = exps.sum(axis=1)
gZs = g_exps.sum(axis=1)
logprob = exps / Zs
g_logprob = g_exps / gZs
gradients[:] = logprob - g_logprob
def step_through(self, Doc doc, GoldParse gold=None):
"""
Set up a stepwise state, to introspect and control the transition sequence.
Arguments:
doc (Doc): The document to step through.
gold (GoldParse): Optional gold parse
Returns (StepwiseState):
A state object, to step through the annotation process.
"""
return StepwiseState(self, doc, gold=gold)
def from_transition_sequence(self, Doc doc, sequence):
"""Control the annotations on a document by specifying a transition sequence
to follow.
Arguments:
doc (Doc): The document to annotate.
sequence: A sequence of action names, as unicode strings.
Returns: None
"""
with self.step_through(doc) as stepwise:
for transition in sequence:
stepwise.transition(transition)
def add_label(self, label):
# Doesn't set label into serializer -- subclasses override it to do that.
for action in self.moves.action_types:
added = self.moves.add_action(action, label)
if added:
# Important that the labels be stored as a list! We need the
# order, or the model goes out of synch
self.cfg.setdefault('extra_labels', []).append(label)
cdef int dropout(FeatureC* feats, int nr_feat, float prob) except -1:
if prob <= 0 or prob >= 1.:
return 0
cdef double[::1] py_probs = numpy.random.uniform(0., 1., nr_feat)
cdef double* probs = &py_probs[0]
for i in range(nr_feat):
if probs[i] >= prob:
feats[i].value /= prob
else:
feats[i].value = 0.
cdef class StepwiseState:
cdef readonly StateClass stcls
cdef readonly Example eg
cdef readonly Doc doc
cdef readonly GoldParse gold
cdef readonly Parser parser
def __init__(self, Parser parser, Doc doc, GoldParse gold=None):
self.parser = parser
self.doc = doc
if gold is not None:
self.gold = gold
self.parser.moves.preprocess_gold(self.gold)
else:
self.gold = GoldParse(doc)
self.stcls = StateClass.init(doc.c, doc.length)
self.parser.moves.initialize_state(self.stcls.c)
self.eg = Example(
nr_class=self.parser.moves.n_moves,
nr_atom=CONTEXT_SIZE,
nr_feat=self.parser.model.nr_feat)
def __enter__(self):
return self
def __exit__(self, type, value, traceback):
self.finish()
@property
def is_final(self):
return self.stcls.is_final()
@property
def stack(self):
return self.stcls.stack
@property
def queue(self):
return self.stcls.queue
@property
def heads(self):
return [self.stcls.H(i) for i in range(self.stcls.c.length)]
@property
def deps(self):
return [self.doc.vocab.strings[self.stcls.c._sent[i].dep]
for i in range(self.stcls.c.length)]
@property
def costs(self):
"""
Find the action-costs for the current state.
"""
if not self.gold:
raise ValueError("Can't set costs: No GoldParse provided")
self.parser.moves.set_costs(self.eg.c.is_valid, self.eg.c.costs,
self.stcls, self.gold)
costs = {}
for i in range(self.parser.moves.n_moves):
if not self.eg.c.is_valid[i]:
continue
transition = self.parser.moves.c[i]
name = self.parser.moves.move_name(transition.move, transition.label)
costs[name] = self.eg.c.costs[i]
return costs
def predict(self):
self.eg.reset()
self.eg.c.nr_feat = self.parser.model.set_featuresC(self.eg.c.atoms, self.eg.c.features,
self.stcls.c)
self.parser.moves.set_valid(self.eg.c.is_valid, self.stcls.c)
self.parser.model.set_scoresC(self.eg.c.scores,
self.eg.c.features, self.eg.c.nr_feat)
cdef Transition action = self.parser.moves.c[self.eg.guess]
return self.parser.moves.move_name(action.move, action.label)
def transition(self, action_name=None):
if action_name is None:
action_name = self.predict()
moves = {'S': 0, 'D': 1, 'L': 2, 'R': 3}
if action_name == '_':
action_name = self.predict()
action = self.parser.moves.lookup_transition(action_name)
elif action_name == 'L' or action_name == 'R':
self.predict()
move = moves[action_name]
clas = _arg_max_clas(self.eg.c.scores, move, self.parser.moves.c,
self.eg.c.nr_class)
action = self.parser.moves.c[clas]
else:
action = self.parser.moves.lookup_transition(action_name)
action.do(self.stcls.c, action.label)
def finish(self):
if self.stcls.is_final():
self.parser.moves.finalize_state(self.stcls.c)
self.doc.set_parse(self.stcls.c._sent)
self.parser.moves.finalize_doc(self.doc)
class ParserStateError(ValueError):
def __init__(self, doc):
ValueError.__init__(self,
"Error analysing doc -- no valid actions available. This should "
"never happen, so please report the error on the issue tracker. "
"Here's the thread to do so --- reopen it if it's closed:\n"
"https://github.com/spacy-io/spaCy/issues/429\n"
"Please include the text that the parser failed on, which is:\n"
"%s" % repr(doc.text))
cdef int arg_max_if_gold(const weight_t* scores, const weight_t* costs, int n) nogil:
cdef int best = -1
for i in range(n):
if costs[i] <= 0:
if best == -1 or scores[i] > scores[best]:
best = i
return best
cdef int _arg_max_clas(const weight_t* scores, int move, const Transition* actions,
int nr_class) except -1:
cdef weight_t score = 0
cdef int mode = -1
cdef int i
for i in range(nr_class):
if actions[i].move == move and (mode == -1 or scores[i] >= score):
mode = i
score = scores[i]
return mode