spaCy/spacy/syntax/beam_parser.pyx
2016-07-24 14:26:52 +02:00

251 lines
9.2 KiB
Cython

# cython: profile=True
# cython: experimental_cpp_class_def=True
# cython: cdivision=True
"""
MALT-style dependency parser
"""
from __future__ import unicode_literals
cimport cython
from cpython.ref cimport PyObject, Py_INCREF, Py_XDECREF
from libc.stdint cimport uint32_t, uint64_t
from libc.string cimport memset, memcpy
from libc.stdlib cimport rand
from libc.math cimport log, exp, isnan, isinf
import random
import os.path
from os import path
import shutil
import json
from cymem.cymem cimport Pool, Address
from murmurhash.mrmr cimport hash64
from thinc.typedefs cimport weight_t, class_t, feat_t, atom_t, hash_t
from util import Config
from thinc.linear.features cimport ConjunctionExtracter
from thinc.structs cimport FeatureC, ExampleC
from thinc.extra.search cimport Beam
from thinc.extra.search cimport MaxViolation
from thinc.extra.eg cimport Example
from ..structs cimport TokenC
from ..tokens.doc cimport Doc
from ..strings cimport StringStore
from .transition_system cimport TransitionSystem, Transition
from ..gold cimport GoldParse
from . import _parse_features
from ._parse_features cimport CONTEXT_SIZE
from ._parse_features cimport fill_context
from .stateclass cimport StateClass
from .parser cimport Parser
from .parser cimport ParserPerceptron
from .parser cimport ParserNeuralNet
DEBUG = False
def set_debug(val):
global DEBUG
DEBUG = val
def get_templates(name):
pf = _parse_features
if name == 'ner':
return pf.ner
elif name == 'debug':
return pf.unigrams
else:
return (pf.unigrams + pf.s0_n0 + pf.s1_n0 + pf.s1_s0 + pf.s0_n1 + pf.n0_n1 + \
pf.tree_shape + pf.trigrams)
cdef int BEAM_WIDTH = 8
MAX_VIOLN_UPDATE = False
cdef class BeamParser(Parser):
cdef public int beam_width
def __init__(self, *args, **kwargs):
self.beam_width = kwargs.get('beam_width', BEAM_WIDTH)
Parser.__init__(self, *args, **kwargs)
cdef int parseC(self, TokenC* tokens, int length, int nr_feat, int nr_class) with gil:
self._parseC(tokens, length, nr_feat, nr_class)
cdef int _parseC(self, TokenC* tokens, int length, int nr_feat, int nr_class) except -1:
cdef Beam beam = Beam(self.moves.n_moves, self.beam_width)
beam.initialize(_init_state, length, tokens)
beam.check_done(_check_final_state, NULL)
while not beam.is_done:
self._advance_beam(beam, None, False)
state = <StateClass>beam.at(0)
self.moves.finalize_state(state.c)
for i in range(length):
tokens[i] = state.c._sent[i]
_cleanup(beam)
def train(self, Doc tokens, GoldParse gold_parse, itn=0):
self.moves.preprocess_gold(gold_parse)
cdef Beam pred = Beam(self.moves.n_moves, self.beam_width)
pred.initialize(_init_state, tokens.length, tokens.c)
pred.check_done(_check_final_state, NULL)
cdef Beam gold = Beam(self.moves.n_moves, self.beam_width)
gold.initialize(_init_state, tokens.length, tokens.c)
gold.check_done(_check_final_state, NULL)
violn = MaxViolation()
while not pred.is_done and not gold.is_done:
# We search separately here, to allow for ambiguity in the gold
# parse.
self._advance_beam(pred, gold_parse, False)
self._advance_beam(gold, gold_parse, True)
if MAX_VIOLN_UPDATE:
violn.check_crf(pred, gold)
if violn.delta >= 10000:
break
elif pred.min_score > gold.score: # Early update
break
if MAX_VIOLN_UPDATE:
self._max_violation_update(
tokens, violn.p_probs, violn.p_hist,
violn.g_probs, violn.g_hist)
else:
self._early_update(tokens, pred, gold)
_cleanup(pred)
_cleanup(gold)
return pred.loss
def _max_violation_update(self, Doc doc, p_grads, p_hist, g_grads, g_hist):
for grad, hist in zip(p_grads, p_hist):
if abs(grad) >= 1e-5:
self._update_dense(doc, hist, grad)
for grad, hist in zip(g_grads, g_hist):
if abs(grad) >= 1e-5:
self._update_dense(doc, hist, -grad)
def _early_update(self, Doc doc, Beam pred, Beam gold):
# Gather the partition function --- Z --- by which we can normalize the
# scores into a probability distribution. The simple idea here is that
# we clip the probability of all parses outside the beam to 0.
cdef long double Z = 0.0
for i in range(pred.size):
# Make sure we've only got negative examples here.
# Otherwise, we might double-count the gold.
if pred._states[i].loss > 0:
Z += exp(pred._states[i].score)
if Z > 0: # If no negative examples, don't update.
Z += exp(gold.score)
for i, hist in enumerate(pred.histories):
if pred._states[i].loss > 0:
# Update with the negative example.
# Gradient of loss is P(parse) - 0
self._update_dense(doc, hist, exp(pred._states[i].score) / Z)
# Update with the positive example.
# Gradient of loss is P(parse) - 1
self._update_dense(doc, gold.histories[0], (exp(gold.score) / Z) - 1)
def _advance_beam(self, Beam beam, GoldParse gold, bint follow_gold):
cdef Example py_eg = Example(nr_class=self.moves.n_moves, nr_atom=CONTEXT_SIZE,
nr_feat=self.model.nr_feat, widths=self.model.widths)
cdef ExampleC* eg = py_eg.c
cdef ParserNeuralNet model = self.model
for i in range(beam.size):
py_eg.reset()
stcls = <StateClass>beam.at(i)
if not stcls.c.is_final():
model.set_featuresC(eg, stcls.c)
model.set_scoresC(beam.scores[i], eg.features, eg.nr_feat, 1)
self.moves.set_valid(beam.is_valid[i], stcls.c)
if gold is not None:
for i in range(beam.size):
py_eg.reset()
stcls = <StateClass>beam.at(i)
if not stcls.c.is_final():
self.moves.set_costs(beam.is_valid[i], beam.costs[i], stcls, gold)
if follow_gold:
for j in range(self.moves.n_moves):
beam.is_valid[i][j] *= beam.costs[i][j] == 0
beam.advance(_transition_state, _hash_state, <void*>self.moves.c)
beam.check_done(_check_final_state, NULL)
def _update_dense(self, Doc doc, history, weight_t loss):
cdef Example py_eg = Example(nr_class=self.moves.n_moves,
nr_atom=CONTEXT_SIZE,
nr_feat=self.model.nr_feat,
widths=self.model.widths)
cdef ExampleC* eg = py_eg.c
cdef ParserNeuralNet model = self.model
stcls = StateClass.init(doc.c, doc.length)
self.moves.initialize_state(stcls.c)
for clas in history:
model.set_featuresC(eg, stcls.c)
self.moves.set_valid(eg.is_valid, stcls.c)
for i in range(self.moves.n_moves):
eg.costs[i] = loss if i == clas else 0
model.updateC(
eg.features, eg.nr_feat, True, eg.costs, eg.is_valid, False)
self.moves.c[clas].do(stcls.c, self.moves.c[clas].label)
py_eg.reset()
def _update(self, Doc tokens, list hist, weight_t inc):
cdef Pool mem = Pool()
cdef atom_t[CONTEXT_SIZE] context
features = <FeatureC*>mem.alloc(self.model.nr_feat, sizeof(FeatureC))
cdef StateClass stcls = StateClass.init(tokens.c, tokens.length)
self.moves.initialize_state(stcls.c)
cdef class_t clas
cdef ParserPerceptron model = self.model
for clas in hist:
fill_context(context, stcls.c)
nr_feat = model.extracter.set_features(features, context)
for feat in features[:nr_feat]:
model.update_weight(feat.key, clas, feat.value * inc)
self.moves.c[clas].do(stcls.c, self.moves.c[clas].label)
# These are passed as callbacks to thinc.search.Beam
cdef int _transition_state(void* _dest, void* _src, class_t clas, void* _moves) except -1:
dest = <StateClass>_dest
src = <StateClass>_src
moves = <const Transition*>_moves
dest.clone(src)
moves[clas].do(dest.c, moves[clas].label)
cdef void* _init_state(Pool mem, int length, void* tokens) except NULL:
cdef StateClass st = StateClass.init(<const TokenC*>tokens, length)
# Ensure sent_start is set to 0 throughout
for i in range(st.c.length):
st.c._sent[i].sent_start = False
st.c._sent[i].l_edge = i
st.c._sent[i].r_edge = i
st.fast_forward()
Py_INCREF(st)
return <void*>st
cdef int _check_final_state(void* _state, void* extra_args) except -1:
return (<StateClass>_state).is_final()
def _cleanup(Beam beam):
for i in range(beam.width):
Py_XDECREF(<PyObject*>beam._states[i].content)
Py_XDECREF(<PyObject*>beam._parents[i].content)
cdef hash_t _hash_state(void* _state, void* _) except 0:
state = <StateClass>_state
return state.c.hash()