fix sample.py from tokenizer changes before

sample.py

@@ -51,11 +51,16 @@ if compile:
     print("Compiling the model...")
     model = torch.compile(model) # requires PyTorch 2.0 (optional)
 
-# load the tokenizer, either provided, or attempt to find it
+# load the tokenizer
+vocab_source = checkpoint_dict.get("vocab_source", "llama2")
+vocab_size = gptconf.vocab_size
 if tokenizer:
+    # a specific tokenizer is provided, use it
     tokenizer_model = tokenizer
 else:
-    tokenizer_model = get_tokenizer_model_path(vocab_size=gptconf.vocab_size)
+    # let's try to find the tokenizer model automatically. bit gross here...
+    query_vocab_size = 0 if vocab_source == "llama2" else vocab_size
+    tokenizer_model = get_tokenizer_model_path(vocab_size=query_vocab_size)
 enc = Tokenizer(tokenizer_model=tokenizer_model)
 
 # encode the beginning of the prompt