transformers pytorch btlm text-generation causal-lm Cerebras BTLM custom_code en dataset:cerebras/SlimPajama-627B arxiv:2304.03208 arxiv:2002.05202 arxiv:2108.12409 arxiv:2203.03466 arxiv:2309.11568 arxiv:2310.13017 license:apache-2.0 autotrain_compatible region:us