from typing import cast, Any, Callable, Dict, Iterable, List, Optional, Union from typing import Tuple from collections import Counter from itertools import islice import numpy as np import srsly from thinc.api import Config, Model, SequenceCategoricalCrossentropy, NumpyOps from thinc.types import ArrayXd, Floats2d, Ints1d from thinc.legacy import LegacySequenceCategoricalCrossentropy from ._edit_tree_internals.edit_trees import EditTrees from ._edit_tree_internals.schemas import validate_edit_tree from .lemmatizer import lemmatizer_score from .trainable_pipe import TrainablePipe from ..errors import Errors from ..language import Language from ..tokens import Doc from ..training import Example, validate_examples, validate_get_examples from ..vocab import Vocab from .. import util ActivationsT = Dict[str, Union[List[Floats2d], List[Ints1d]]] # The cutoff value of *top_k* above which an alternative method is used to process guesses. TOP_K_GUARDRAIL = 20 default_model_config = """ [model] @architectures = "spacy.Tagger.v2" [model.tok2vec] @architectures = "spacy.HashEmbedCNN.v2" pretrained_vectors = null width = 96 depth = 4 embed_size = 2000 window_size = 1 maxout_pieces = 3 subword_features = true """ DEFAULT_EDIT_TREE_LEMMATIZER_MODEL = Config().from_str(default_model_config)["model"] @Language.factory( "trainable_lemmatizer", assigns=["token.lemma"], requires=[], default_config={ "model": DEFAULT_EDIT_TREE_LEMMATIZER_MODEL, "backoff": "orth", "min_tree_freq": 3, "overwrite": False, "top_k": 1, "scorer": {"@scorers": "spacy.lemmatizer_scorer.v1"}, "save_activations": False, }, default_score_weights={"lemma_acc": 1.0}, ) def make_edit_tree_lemmatizer( nlp: Language, name: str, model: Model, backoff: Optional[str], min_tree_freq: int, overwrite: bool, top_k: int, scorer: Optional[Callable], save_activations: bool, ): """Construct an EditTreeLemmatizer component.""" return EditTreeLemmatizer( nlp.vocab, model, name, backoff=backoff, min_tree_freq=min_tree_freq, overwrite=overwrite, top_k=top_k, scorer=scorer, save_activations=save_activations, ) class EditTreeLemmatizer(TrainablePipe): """ Lemmatizer that lemmatizes each word using a predicted edit tree. """ def __init__( self, vocab: Vocab, model: Model, name: str = "trainable_lemmatizer", *, backoff: Optional[str] = "orth", min_tree_freq: int = 3, overwrite: bool = False, top_k: int = 1, scorer: Optional[Callable] = lemmatizer_score, save_activations: bool = False, ): """ Construct an edit tree lemmatizer. backoff (Optional[str]): backoff to use when the predicted edit trees are not applicable. Must be an attribute of Token or None (leave the lemma unset). min_tree_freq (int): prune trees that are applied less than this frequency in the training data. overwrite (bool): overwrite existing lemma annotations. top_k (int): try to apply at most the k most probable edit trees. save_activations (bool): save model activations in Doc when annotating. """ self.vocab = vocab self.model = model self.name = name self.backoff = backoff self.min_tree_freq = min_tree_freq self.overwrite = overwrite self.top_k = top_k self.trees = EditTrees(self.vocab.strings) self.tree2label: Dict[int, int] = {} self.cfg: Dict[str, Any] = {"labels": []} self.scorer = scorer self.save_activations = save_activations self.numpy_ops = NumpyOps() def get_loss( self, examples: Iterable[Example], scores: List[Floats2d] ) -> Tuple[float, List[Floats2d]]: validate_examples(examples, "EditTreeLemmatizer.get_loss") loss_func = LegacySequenceCategoricalCrossentropy( normalize=False, missing_value=-1 ) truths = [] for eg in examples: eg_truths = [] for (predicted, gold_lemma) in zip( eg.predicted, eg.get_aligned("LEMMA", as_string=True) ): if gold_lemma is None or gold_lemma == "": label = -1 else: tree_id = self.trees.add(predicted.text, gold_lemma) label = self.tree2label.get(tree_id, 0) eg_truths.append(label) truths.append(eg_truths) d_scores, loss = loss_func(scores, truths) if self.model.ops.xp.isnan(loss): raise ValueError(Errors.E910.format(name=self.name)) return float(loss), d_scores def get_teacher_student_loss( self, teacher_scores: List[Floats2d], student_scores: List[Floats2d] ) -> Tuple[float, List[Floats2d]]: """Calculate the loss and its gradient for a batch of student scores, relative to teacher scores. teacher_scores: Scores representing the teacher model's predictions. student_scores: Scores representing the student model's predictions. RETURNS (Tuple[float, float]): The loss and the gradient. DOCS: https://spacy.io/api/edittreelemmatizer#get_teacher_student_loss """ loss_func = LegacySequenceCategoricalCrossentropy(normalize=False) d_scores, loss = loss_func(student_scores, teacher_scores) if self.model.ops.xp.isnan(loss): raise ValueError(Errors.E910.format(name=self.name)) return float(loss), d_scores def predict(self, docs: Iterable[Doc]) -> ActivationsT: if self.top_k == 1: scores2guesses = self._scores2guesses_top_k_equals_1 elif self.top_k <= TOP_K_GUARDRAIL: scores2guesses = self._scores2guesses_top_k_greater_1 else: scores2guesses = self._scores2guesses_top_k_guardrail # The behaviour of *_scores2guesses_top_k_greater_1()* is efficient for values # of *top_k>1* that are likely to be useful when the edit tree lemmatizer is used # for its principal purpose of lemmatizing tokens. However, the code could also # be used for other purposes, and with very large values of *top_k* the method # becomes inefficient. In such cases, *_scores2guesses_top_k_guardrail()* is used # instead. n_docs = len(list(docs)) if not any(len(doc) for doc in docs): # Handle cases where there are no tokens in any docs. n_labels = len(self.cfg["labels"]) guesses: List[Ints1d] = [ self.model.ops.alloc((0,), dtype="i") for doc in docs ] scores: List[Floats2d] = [ self.model.ops.alloc((0, n_labels), dtype="i") for doc in docs ] assert len(guesses) == n_docs return {"probabilities": scores, "tree_ids": guesses} scores = self.model.predict(docs) assert len(scores) == n_docs guesses = scores2guesses(docs, scores) assert len(guesses) == n_docs return {"probabilities": scores, "tree_ids": guesses} def _scores2guesses_top_k_equals_1(self, docs, scores): guesses = [] for doc, doc_scores in zip(docs, scores): doc_guesses = doc_scores.argmax(axis=1) doc_guesses = self.numpy_ops.asarray(doc_guesses) doc_compat_guesses = [] for i, token in enumerate(doc): tree_id = self.cfg["labels"][doc_guesses[i]] if self.trees.apply(tree_id, token.text) is not None: doc_compat_guesses.append(tree_id) else: doc_compat_guesses.append(-1) guesses.append(np.array(doc_compat_guesses)) return guesses def _scores2guesses_top_k_greater_1(self, docs, scores): guesses = [] top_k = min(self.top_k, len(self.labels)) for doc, doc_scores in zip(docs, scores): doc_scores = self.numpy_ops.asarray(doc_scores) doc_compat_guesses = [] for i, token in enumerate(doc): for _ in range(top_k): candidate = int(doc_scores[i].argmax()) candidate_tree_id = self.cfg["labels"][candidate] if self.trees.apply(candidate_tree_id, token.text) is not None: doc_compat_guesses.append(candidate_tree_id) break doc_scores[i, candidate] = np.finfo(np.float32).min else: doc_compat_guesses.append(-1) guesses.append(np.array(doc_compat_guesses)) return guesses def _scores2guesses_top_k_guardrail(self, docs, scores): guesses = [] for doc, doc_scores in zip(docs, scores): doc_guesses = np.argsort(doc_scores)[..., : -self.top_k - 1 : -1] doc_guesses = self.numpy_ops.asarray(doc_guesses) doc_compat_guesses = [] for token, candidates in zip(doc, doc_guesses): tree_id = -1 for candidate in candidates: candidate_tree_id = self.cfg["labels"][candidate] if self.trees.apply(candidate_tree_id, token.text) is not None: tree_id = candidate_tree_id break doc_compat_guesses.append(tree_id) guesses.append(np.array(doc_compat_guesses)) return guesses def set_annotations(self, docs: Iterable[Doc], activations: ActivationsT): batch_tree_ids = activations["tree_ids"] for i, doc in enumerate(docs): if self.save_activations: doc.activations[self.name] = {} for act_name, acts in activations.items(): doc.activations[self.name][act_name] = acts[i] doc_tree_ids = batch_tree_ids[i] if hasattr(doc_tree_ids, "get"): doc_tree_ids = doc_tree_ids.get() for j, tree_id in enumerate(doc_tree_ids): if self.overwrite or doc[j].lemma == 0: # If no applicable tree could be found during prediction, # the special identifier -1 is used. Otherwise the tree # is guaranteed to be applicable. if tree_id == -1: if self.backoff is not None: doc[j].lemma = getattr(doc[j], self.backoff) else: lemma = self.trees.apply(tree_id, doc[j].text) doc[j].lemma_ = lemma @property def labels(self) -> Tuple[int, ...]: """Returns the labels currently added to the component.""" return tuple(self.cfg["labels"]) @property def hide_labels(self) -> bool: return True @property def label_data(self) -> Dict: trees = [] for tree_id in range(len(self.trees)): tree = self.trees[tree_id] if "orig" in tree: tree["orig"] = self.vocab.strings[tree["orig"]] if "subst" in tree: tree["subst"] = self.vocab.strings[tree["subst"]] trees.append(tree) return dict(trees=trees, labels=tuple(self.cfg["labels"])) def initialize( self, get_examples: Callable[[], Iterable[Example]], *, nlp: Optional[Language] = None, labels: Optional[Dict] = None, ): validate_get_examples(get_examples, "EditTreeLemmatizer.initialize") if labels is None: self._labels_from_data(get_examples) else: self._add_labels(labels) # Sample for the model. doc_sample = [] label_sample = [] for example in islice(get_examples(), 10): doc_sample.append(example.x) gold_labels: List[List[float]] = [] for token in example.reference: if token.lemma == 0: gold_label = None else: gold_label = self._pair2label(token.text, token.lemma_) gold_labels.append( [ 1.0 if label == gold_label else 0.0 for label in self.cfg["labels"] ] ) gold_labels = cast(Floats2d, gold_labels) label_sample.append(self.model.ops.asarray(gold_labels, dtype="float32")) self._require_labels() assert len(doc_sample) > 0, Errors.E923.format(name=self.name) assert len(label_sample) > 0, Errors.E923.format(name=self.name) self.model.initialize(X=doc_sample, Y=label_sample) def from_bytes(self, bytes_data, *, exclude=tuple()): deserializers = { "cfg": lambda b: self.cfg.update(srsly.json_loads(b)), "model": lambda b: self.model.from_bytes(b), "vocab": lambda b: self.vocab.from_bytes(b, exclude=exclude), "trees": lambda b: self.trees.from_bytes(b), } util.from_bytes(bytes_data, deserializers, exclude) return self def to_bytes(self, *, exclude=tuple()): serializers = { "cfg": lambda: srsly.json_dumps(self.cfg), "model": lambda: self.model.to_bytes(), "vocab": lambda: self.vocab.to_bytes(exclude=exclude), "trees": lambda: self.trees.to_bytes(), } return util.to_bytes(serializers, exclude) def to_disk(self, path, exclude=tuple()): path = util.ensure_path(path) serializers = { "cfg": lambda p: srsly.write_json(p, self.cfg), "model": lambda p: self.model.to_disk(p), "vocab": lambda p: self.vocab.to_disk(p, exclude=exclude), "trees": lambda p: self.trees.to_disk(p), } util.to_disk(path, serializers, exclude) def from_disk(self, path, exclude=tuple()): def load_model(p): try: with open(p, "rb") as mfile: self.model.from_bytes(mfile.read()) except AttributeError: raise ValueError(Errors.E149) from None deserializers = { "cfg": lambda p: self.cfg.update(srsly.read_json(p)), "model": load_model, "vocab": lambda p: self.vocab.from_disk(p, exclude=exclude), "trees": lambda p: self.trees.from_disk(p), } util.from_disk(path, deserializers, exclude) return self def _add_labels(self, labels: Dict): if "labels" not in labels: raise ValueError(Errors.E857.format(name="labels")) if "trees" not in labels: raise ValueError(Errors.E857.format(name="trees")) self.cfg["labels"] = list(labels["labels"]) trees = [] for tree in labels["trees"]: errors = validate_edit_tree(tree) if errors: raise ValueError(Errors.E1026.format(errors="\n".join(errors))) tree = dict(tree) if "orig" in tree: tree["orig"] = self.vocab.strings.add(tree["orig"]) if "orig" in tree: tree["subst"] = self.vocab.strings.add(tree["subst"]) trees.append(tree) self.trees.from_json(trees) for label, tree in enumerate(self.labels): self.tree2label[tree] = label def _labels_from_data(self, get_examples: Callable[[], Iterable[Example]]): # Count corpus tree frequencies in ad-hoc storage to avoid cluttering # the final pipe/string store. vocab = Vocab() trees = EditTrees(vocab.strings) tree_freqs: Counter = Counter() repr_pairs: Dict = {} for example in get_examples(): for token in example.reference: if token.lemma != 0: tree_id = trees.add(token.text, token.lemma_) tree_freqs[tree_id] += 1 repr_pairs[tree_id] = (token.text, token.lemma_) # Construct trees that make the frequency cut-off using representative # form - token pairs. for tree_id, freq in tree_freqs.items(): if freq >= self.min_tree_freq: form, lemma = repr_pairs[tree_id] self._pair2label(form, lemma, add_label=True) def _pair2label(self, form, lemma, add_label=False): """ Look up the edit tree identifier for a form/label pair. If the edit tree is unknown and "add_label" is set, the edit tree will be added to the labels. """ tree_id = self.trees.add(form, lemma) if tree_id not in self.tree2label: if not add_label: return None self.tree2label[tree_id] = len(self.cfg["labels"]) self.cfg["labels"].append(tree_id) return self.tree2label[tree_id]