spaCy/spacy/syntax/parser.pyx

138 lines
4.3 KiB
Cython

# cython: profile=True
"""
MALT-style dependency parser
"""
from __future__ import unicode_literals
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, Transition
from ._state cimport init_state, State, is_final, get_idx, get_s0, get_s1
from . import _parse_features
from ._parse_features cimport fill_context, CONTEXT_SIZE
DEBUG = False
def set_debug(val):
global DEBUG
DEBUG = val
cdef unicode print_state(State* s, list words):
words = list(words) + ['EOL']
top = words[s.stack[0]]
second = words[s.stack[-1]]
n0 = words[s.i]
n1 = words[s.i + 1]
return ' '.join((second, top, '|', n0, n1))
def get_templates(name):
pf = _parse_features
if name == 'zhang':
return pf.arc_eager
else:
templs = pf.unigrams + pf.s0_n0 + pf.s1_n0 + pf.s0_n1 + pf.n0_n1 + pf.tree_shape + pf.trigrams
return templs
cdef class GreedyParser:
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
const weight_t* scores
Transition guess
cdef atom_t[CONTEXT_SIZE] context
cdef int n_feats
cdef Pool mem = Pool()
cdef State* state = init_state(mem, tokens.data, tokens.length)
while not is_final(state):
fill_context(context, state)
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)
return 0
def train_sent(self, Tokens tokens, list gold_heads, list gold_labels):
cdef:
Feature* feats
weight_t* scores
Transition guess
Transition gold
cdef int n_feats
cdef atom_t[CONTEXT_SIZE] context
cdef Pool mem = Pool()
cdef int* heads_array = <int*>mem.alloc(tokens.length, sizeof(int))
cdef int* labels_array = <int*>mem.alloc(tokens.length, sizeof(int))
cdef int i
for i in range(tokens.length):
heads_array[i] = gold_heads[i]
labels_array[i] = self.moves.label_ids[gold_labels[i]]
cdef State* state = init_state(mem, tokens.data, tokens.length)
while not is_final(state):
fill_context(context, state)
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(&guess, scores, state, heads_array, labels_array)
counts = _get_counts(guess.clas, best.clas, feats, n_feats, guess.cost)
self.model.update(counts)
self.moves.transition(state, &guess)
cdef int n_corr = 0
for i in range(tokens.length):
n_corr += (i + state.sent[i].head) == gold_heads[i]
return n_corr
cdef dict _get_counts(int guess, int best, const Feature* feats, const int n_feats,
int inc):
if guess == best:
return {}
gold_counts = {}
guess_counts = {}
cdef int i
for i in range(n_feats):
key = (feats[i].i, feats[i].key)
if key in gold_counts:
gold_counts[key] += (feats[i].value * inc)
guess_counts[key] -= (feats[i].value * inc)
else:
gold_counts[key] = (feats[i].value * inc)
guess_counts[key] = -(feats[i].value * inc)
return {guess: guess_counts, best: gold_counts}