transformers safetensors mixtral text-generation reasoning preference_learning nca dataset:openbmb/UltraInteract_sft dataset:openbmb/UltraInteract_pair dataset:openbmb/UltraFeedback arxiv:2404.02078 arxiv:2402.01306 license:apache-2.0 autotrain_compatible text-generation-inference endpoints_compatible region:us