spaCy/website/usage/_processing-pipelines/_user-hooks.jade
2017-10-03 14:26:20 +02:00

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//- 💫 DOCS > USAGE > PROCESSING PIPELINES > ATTRIBUTE HOOKS
p
| Hooks let you customize some of the behaviours of the #[code Doc],
| #[code Span] or #[code Token] objects by adding a component to the
| pipeline. For instance, to customize the
| #[+api("doc#similarity") #[code Doc.similarity]] method, you can add a
| component that sets a custom function to
| #[code doc.user_hooks['similarity']]. The built-in #[code Doc.similarity]
| method will check the #[code user_hooks] dict, and delegate to your
| function if you've set one. Similar results can be achieved by setting
| functions to #[code Doc.user_span_hooks] and #[code Doc.user_token_hooks].
+code("Polymorphic similarity example").
span.similarity(doc)
token.similarity(span)
doc1.similarity(doc2)
p
| By default, this just averages the vectors for each document, and
| computes their cosine. Obviously, spaCy should make it easy for you to
| install your own similarity model. This introduces a tricky design
| challenge. The current solution is to add three more dicts to the
| #[code Doc] object:
+aside("Implementation note")
| The hooks live on the #[code Doc] object because the #[code Span] and
| #[code Token] objects are created lazily, and don't own any data. They
| just proxy to their parent #[code Doc]. This turns out to be convenient
| here — we only have to worry about installing hooks in one place.
+table(["Name", "Description"])
+row
+cell #[code user_hooks]
+cell Customise behaviour of #[code doc.vector], #[code doc.has_vector], #[code doc.vector_norm] or #[code doc.sents]
+row
+cell #[code user_token_hooks]
+cell Customise behaviour of #[code token.similarity], #[code token.vector], #[code token.has_vector], #[code token.vector_norm] or #[code token.conjuncts]
+row
+cell #[code user_span_hooks]
+cell Customise behaviour of #[code span.similarity], #[code span.vector], #[code span.has_vector], #[code span.vector_norm] or #[code span.root]
p
| To sum up, here's an example of hooking in custom #[code .similarity()]
| methods:
+code("Add custom similarity hooks").
class SimilarityModel(object):
def __init__(self, model):
self._model = model
def __call__(self, doc):
doc.user_hooks['similarity'] = self.similarity
doc.user_span_hooks['similarity'] = self.similarity
doc.user_token_hooks['similarity'] = self.similarity
def similarity(self, obj1, obj2):
y = self._model([obj1.vector, obj2.vector])
return float(y[0])