spaCy/spacy/parser/parser.pyx
2014-12-16 08:06:04 +11:00

161 lines
5.0 KiB
Cython

# cython: profile=True
"""
MALT-style dependency parser
"""
cimport cython
import random
import os.path
from os.path import join as pjoin
import shutil
import json
from cymem.cymem cimport Pool, Address
from thinc.typedefs cimport weight_t, class_t, feat_t, atom_t
from util import Config
from thinc.features cimport Extractor
from thinc.features cimport Feature
from thinc.features cimport count_feats
from thinc.learner cimport LinearModel
from ..tokens cimport Tokens, TokenC
from .arc_eager cimport TransitionSystem
from ._state cimport init_state, State, is_final, get_s1
VOCAB_SIZE = 1e6
TAG_SET_SIZE = 50
DEF CONTEXT_SIZE = 50
DEBUG = False
def set_debug(val):
global DEBUG
DEBUG = val
cdef str print_state(State* s, list words):
top = words[s.top]
second = words[get_s1(s)]
n0 = words[s.i]
n1 = words[s.i + 1]
return ' '.join((second, top, '|', n0, n1))
def train(sents, golds, model_dir, n_iter=15, feat_set=u'basic', seed=0):
if os.path.exists(model_dir):
shutil.rmtree(model_dir)
os.mkdir(model_dir)
left_labels, right_labels, dfl_labels = get_labels(golds)
Config.write(model_dir, 'config', features=feat_set, seed=seed,
left_labels=left_labels, right_labels=right_labels)
parser = Parser(model_dir)
indices = list(range(len(sents)))
for n in range(n_iter):
for i in indices:
parser.train_sent(sents[i], *golds[i])
#parser.tagger.train_sent(py_sent) # TODO
acc = float(parser.guide.n_corr) / parser.guide.total
print(parser.guide.end_train_iter(n) + '\t' +
parser.tagger.guide.end_train_iter(n))
random.shuffle(indices)
parser.guide.end_training()
parser.tagger.guide.end_training()
parser.guide.dump(pjoin(model_dir, 'model'), freq_thresh=0)
parser.tagger.guide.dump(pjoin(model_dir, 'tagger'))
return acc
def get_labels(sents):
'''Get alphabetically-sorted lists of left, right and disfluency labels that
occur in a sample of sentences. Used to determine the set of legal transitions
from the training set.
Args:
sentences (list[Input]): A list of Input objects, usually the training set.
Returns:
labels (tuple[list, list, list]): Sorted lists of left, right and disfluency
labels.
'''
left_labels = set()
right_labels = set()
# TODO
return list(sorted(left_labels)), list(sorted(right_labels))
def get_templates(feats_str):
'''Interpret feats_str, returning a list of template tuples. Each template
is a tuple of numeric indices, referring to positions in the context
array. See _parse_features.pyx for examples. The templates are applied by
thinc.features.Extractor, which picks out the appointed values and hashes
the resulting array, to produce a single feature code.
'''
return tuple()
cdef class Parser:
def __init__(self, model_dir):
assert os.path.exists(model_dir) and os.path.isdir(model_dir)
self.cfg = Config.read(model_dir, 'config')
self.extractor = Extractor(get_templates(self.cfg.features))
self.moves = TransitionSystem(self.cfg.left_labels, self.cfg.right_labels)
self.model = LinearModel(self.moves.n_moves, self.extractor.n_templ)
if os.path.exists(pjoin(model_dir, 'model')):
self.model.load(pjoin(model_dir, 'model'))
cpdef int parse(self, Tokens tokens) except -1:
cdef:
Feature* feats
weight_t* scores
cdef atom_t[CONTEXT_SIZE] context
cdef int n_feats
cdef Pool mem = Pool()
cdef State* state = init_state(mem, tokens.length)
while not is_final(state):
fill_context(context, state, tokens.data) # TODO
feats = self.extractor.get_feats(context, &n_feats)
scores = self.model.get_scores(feats, n_feats)
guess = self.moves.best_valid(scores, state)
self.moves.transition(state, guess)
# TODO output
def train_sent(self, Tokens tokens, list gold_heads, list gold_labels):
cdef:
Feature* feats
weight_t* scores
cdef int n_feats
cdef atom_t[CONTEXT_SIZE] context
cdef Pool mem = Pool()
cdef State* state = init_state(mem, tokens.length)
while not is_final(state):
fill_context(context, state, tokens.data) # TODO
feats = self.extractor.get_feats(context, &n_feats)
scores = self.model.get_scores(feats, n_feats)
guess = self.moves.best_valid(scores, state)
best = self.moves.best_gold(scores, state, gold_heads, gold_labels)
counts = {guess: {}, best: {}}
if guess != best:
count_feats(counts[guess], feats, n_feats, -1)
count_feats(counts[best], feats, n_feats, 1)
self.model.update(counts)
self.moves.transition(state, guess)
cdef int fill_context(atom_t* context, State* s, TokenC* sent) except -1:
pass