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from transformers import Pipeline
import torch.nn.functional as F
import torch
# copied from the model card
def mean_pooling(model_output, attention_mask):
token_embeddings = model_output[0] #First element of model_output contains all token embeddings
input_mask_expanded = attention_mask.unsqueeze(-1).expand(token_embeddings.size()).float()
return torch.sum(token_embeddings * input_mask_expanded, 1) / torch.clamp(input_mask_expanded.sum(1), min=1e-9)
class SentenceEmbeddingPipeline(Pipeline):
def _sanitize_parameters(self, **kwargs):
# we don't have any hyperameters to sanitize
preprocess_kwargs = {}
return preprocess_kwargs, {}, {}
def preprocess(self, inputs):
encoded_inputs = self.tokenizer(inputs, padding=True, truncation=True, return_tensors='pt')
return encoded_inputs
def _forward(self, model_inputs):
outputs = self.model(**model_inputs)
return {"outputs": outputs, "attention_mask": model_inputs["attention_mask"]}
def postprocess(self, model_outputs):
# Perform pooling
sentence_embeddings = mean_pooling(model_outputs["outputs"], model_outputs['attention_mask'])
# Normalize embeddings
sentence_embeddings = F.normalize(sentence_embeddings, p=2, dim=1)
return sentence_embeddings