spaCy/spacy/kb.pxd
2019-04-24 23:52:34 +02:00

160 lines
6.3 KiB
Cython

"""Knowledge-base for entity or concept linking."""
from cymem.cymem cimport Pool
from preshed.maps cimport PreshMap
from libcpp.vector cimport vector
from libc.stdint cimport int32_t, int64_t
from libc.stdio cimport FILE
from spacy.vocab cimport Vocab
from .typedefs cimport hash_t
from .structs cimport EntryC, AliasC
ctypedef vector[EntryC] entry_vec
ctypedef vector[AliasC] alias_vec
# Object used by the Entity Linker that summarizes one entity-alias candidate combination.
cdef class Candidate:
cdef readonly KnowledgeBase kb
cdef hash_t entity_hash
cdef float entity_freq
cdef hash_t alias_hash
cdef float prior_prob
cdef class KnowledgeBase:
cdef Pool mem
cpdef readonly Vocab vocab
# This maps 64bit keys (hash of unique entity string)
# to 64bit values (position of the _EntryC struct in the _entries vector).
# The PreshMap is pretty space efficient, as it uses open addressing. So
# the only overhead is the vacancy rate, which is approximately 30%.
cdef PreshMap _entry_index
# Each entry takes 128 bits, and again we'll have a 30% or so overhead for
# over allocation.
# In total we end up with (N*128*1.3)+(N*128*1.3) bits for N entries.
# Storing 1m entries would take 41.6mb under this scheme.
cdef entry_vec _entries
# This maps 64bit keys (hash of unique alias string)
# to 64bit values (position of the _AliasC struct in the _aliases_table vector).
cdef PreshMap _alias_index
# This should map mention hashes to (entry_id, prob) tuples. The probability
# should be P(entity | mention), which is pretty important to know.
# We can pack both pieces of information into a 64-bit value, to keep things
# efficient.
cdef alias_vec _aliases_table
# This is the part which might take more space: storing various
# categorical features for the entries, and storing vectors for disambiguation
# and possibly usage.
# If each entry gets a 300-dimensional vector, for 1m entries we would need
# 1.2gb. That gets expensive fast. What might be better is to avoid learning
# a unique vector for every entity. We could instead have a compositional
# model, that embeds different features of the entities into vectors. We'll
# still want some per-entity features, like the Wikipedia text or entity
# co-occurrence. Hopefully those vectors can be narrow, e.g. 64 dimensions.
cdef object _vectors_table
# It's very useful to track categorical features, at least for output, even
# if they're not useful in the model itself. For instance, we should be
# able to track stuff like a person's date of birth or whatever. This can
# easily make the KB bigger, but if this isn't needed by the model, and it's
# optional data, we can let users configure a DB as the backend for this.
cdef object _features_table
cdef inline int64_t c_add_entity(self, hash_t entity_hash, float prob,
int32_t* vector_rows, int feats_row) nogil:
"""Add an entry to the vector of entries.
After calling this method, make sure to update also the _entry_index using the return value"""
# This is what we'll map the entity hash key to. It's where the entry will sit
# in the vector of entries, so we can get it later.
cdef int64_t new_index = self._entries.size()
# Avoid struct initializer to enable nogil, cf https://github.com/cython/cython/issues/1642
cdef EntryC entry
entry.entity_hash = entity_hash
entry.vector_rows = vector_rows
entry.feats_row = feats_row
entry.prob = prob
self._entries.push_back(entry)
return new_index
cdef inline int64_t c_add_aliases(self, hash_t alias_hash, vector[int64_t] entry_indices, vector[float] probs) nogil:
"""Connect a mention to a list of potential entities with their prior probabilities .
After calling this method, make sure to update also the _alias_index using the return value"""
# This is what we'll map the alias hash key to. It's where the alias will be defined
# in the vector of aliases.
cdef int64_t new_index = self._aliases_table.size()
# Avoid struct initializer to enable nogil
cdef AliasC alias
alias.entry_indices = entry_indices
alias.probs = probs
self._aliases_table.push_back(alias)
return new_index
cdef inline void _create_empty_vectors(self, hash_t dummy_hash) nogil:
"""
Initializing the vectors and making sure the first element of each vector is a dummy,
because the PreshMap maps pointing to indices in these vectors can not contain 0 as value
cf. https://github.com/explosion/preshed/issues/17
"""
cdef int32_t dummy_value = 0
# Avoid struct initializer to enable nogil
cdef EntryC entry
entry.entity_hash = dummy_hash
entry.vector_rows = &dummy_value
entry.feats_row = dummy_value
entry.prob = dummy_value
# Avoid struct initializer to enable nogil
cdef vector[int64_t] dummy_entry_indices
dummy_entry_indices.push_back(0)
cdef vector[float] dummy_probs
dummy_probs.push_back(0)
cdef AliasC alias
alias.entry_indices = dummy_entry_indices
alias.probs = dummy_probs
self._entries.push_back(entry)
self._aliases_table.push_back(alias)
cpdef load_bulk(self, loc)
cdef class Writer:
cdef FILE* _fp
cdef int write_header(self, int64_t nr_entries) except -1
cdef int write_entry(self, hash_t entry_hash, float entry_prob) except -1
cdef int write_alias_length(self, int64_t alias_length) except -1
cdef int write_alias_header(self, hash_t alias_hash, int64_t candidate_length) except -1
cdef int write_alias(self, int64_t entry_index, float prob) except -1
cdef int _write(self, void* value, size_t size) except -1
cdef class Reader:
cdef FILE* _fp
cdef int read_header(self, int64_t* nr_entries) except -1
cdef int read_entry(self, hash_t* entity_hash, float* prob) except -1
cdef int read_alias_length(self, int64_t* alias_length) except -1
cdef int read_alias_header(self, hash_t* alias_hash, int64_t* candidate_length) except -1
cdef int read_alias(self, int64_t* entry_index, float* prob) except -1
cdef int _read(self, void* value, size_t size) except -1