examples/applications/cross-encoder/cross-encoder_usage.py

"""
This example computes the score between a query and all possible
sentences in a corpus using a Cross-Encoder for semantic textual similarity (STS).
It output then the most similar sentences for the given query.
"""
from sentence_transformers.cross_encoder import CrossEncoder
import numpy as np

# Pre-trained cross encoder
model = CrossEncoder('cross-encoder/stsb-distilroberta-base')

# We want to compute the similarity between the query sentence
query = 'A man is eating pasta.'

# With all sentences in the corpus
corpus = ['A man is eating food.',
          'A man is eating a piece of bread.',
          'The girl is carrying a baby.',
          'A man is riding a horse.',
          'A woman is playing violin.',
          'Two men pushed carts through the woods.',
          'A man is riding a white horse on an enclosed ground.',
          'A monkey is playing drums.',
          'A cheetah is running behind its prey.'
          ]

# So we create the respective sentence combinations
sentence_combinations = [[query, corpus_sentence] for corpus_sentence in corpus]

# Compute the similarity scores for these combinations
similarity_scores = model.predict(sentence_combinations)

# Sort the scores in decreasing order
sim_scores_argsort = reversed(np.argsort(similarity_scores))

# Print the scores
print("Query:", query)
for idx in sim_scores_argsort:
    print("{:.2f}\t{}".format(similarity_scores[idx], corpus[idx]))