sentence-transformers safetensors mpnet sentence-similarity feature-extraction generated_from_trainer dataset_size:800 loss:TripletLoss arxiv:1908.10084 arxiv:1703.07737 base_model:sentence-transformers/all-mpnet-base-v2 base_model:finetune:sentence-transformers/all-mpnet-base-v2 autotrain_compatible endpoints_compatible region:us