add mixed_precision argument on ppl wikitext evaluation (#11813)

* fix: delete ipex extension import in ppl wikitext evaluation

* feat: add mixed_precision argument on ppl wikitext evaluation

* fix: delete mix_precision command in perplex evaluation for wikitext

* fix: remove fp16 mixed-presicion argument

* fix: Add a space.

---------

Co-authored-by: Jinhe Tang <[email protected]>

python/llm/dev/benchmark/perplexity/run_wikitext.py

@@ -20,7 +20,7 @@
 import argparse
 import torch
 from tqdm import tqdm
-from datasets import concatenate_datasets, load_dataset
+from datasets import load_dataset
 from ipex_llm.utils.common import invalidInputError
 
 
@@ -34,6 +34,7 @@
 parser.add_argument("--precision", type=str, default="sym_int4")
 parser.add_argument("--use-cache", action="store_true")
 parser.add_argument("--max_length", type=int, default=None)
+parser.add_argument("--mixed_precision", action="store_true") 
 args = parser.parse_args()
 
 if args.precision == "fp16":  # ipex fp16
@@ -43,7 +44,7 @@
 else:  # ipex-llm
     from ipex_llm.transformers import AutoModelForCausalLM
     model = AutoModelForCausalLM.from_pretrained(args.model_path, load_in_low_bit=args.precision,
-                                                 use_cache=args.use_cache, trust_remote_code=True)
+                                                 use_cache=args.use_cache, trust_remote_code=True, mixed_precision= args.mixed_precision)   
     model = model.half()
 model = model.to(args.device)
 model = model.eval()