add support for truncate arg for HuggingFaceTextGenInference class (#7728)

Fixes https://github.com/hwchase17/langchain/issues/7650

* add support for `truncate` argument of `HugginFaceTextGenInference`

@baskaryan

langchain/llms/huggingface_text_gen_inference.py

@@ -25,6 +25,7 @@ class HuggingFaceTextGenInference(LLM):
     - typical_p: The typical probability threshold for generating text.
     - temperature: The temperature to use when generating text.
     - repetition_penalty: The repetition penalty to use when generating text.
+    - truncate: truncate inputs tokens to the given size
     - stop_sequences: A list of stop sequences to use when generating text.
     - seed: The seed to use when generating text.
     - inference_server_url: The URL of the inference server to use.
@@ -80,6 +81,7 @@ class HuggingFaceTextGenInference(LLM):
     typical_p: Optional[float] = 0.95
     temperature: float = 0.8
     repetition_penalty: Optional[float] = None
+    truncate: Optional[int] = None
     stop_sequences: List[str] = Field(default_factory=list)
     seed: Optional[int] = None
     inference_server_url: str = ""
@@ -145,6 +147,7 @@ class HuggingFaceTextGenInference(LLM):
                 typical_p=self.typical_p,
                 temperature=self.temperature,
                 repetition_penalty=self.repetition_penalty,
+                truncate=self.truncate,
                 seed=self.seed,
                 **kwargs,
             )
@@ -169,6 +172,7 @@ class HuggingFaceTextGenInference(LLM):
                 "typical_p": self.typical_p,
                 "temperature": self.temperature,
                 "repetition_penalty": self.repetition_penalty,
+                "truncate": self.truncate,
                 "seed": self.seed,
             }
             text = ""
@@ -209,6 +213,7 @@ class HuggingFaceTextGenInference(LLM):
                 typical_p=self.typical_p,
                 temperature=self.temperature,
                 repetition_penalty=self.repetition_penalty,
+                truncate=self.truncate,
                 seed=self.seed,
                 **kwargs,
             )
@@ -234,6 +239,7 @@ class HuggingFaceTextGenInference(LLM):
                     "typical_p": self.typical_p,
                     "temperature": self.temperature,
                     "repetition_penalty": self.repetition_penalty,
+                    "truncate": self.truncate,
                     "seed": self.seed,
                 },
                 **kwargs,