[Feature] Allow explicitly setting the temperature for API model (#121)

* allow explicitly setting the temperature

* update

opencompass/models/openai_api.py

@@ -12,6 +12,7 @@ from opencompass.utils.prompt import PromptList
 from .base_api import BaseAPIModel
 
 PromptType = Union[PromptList, str]
+OPENAI_API_BASE = 'https://api.openai.com/v1/chat/completions'
 
 
 @MODELS.register_module()
@@ -40,21 +41,24 @@ class OpenAI(BaseAPIModel):
             wrapping of any meta instructions.
         openai_api_base (str): The base url of OpenAI's API. Defaults to
             'https://api.openai.com/v1/chat/completions'.
+        temperature (float, optional): What sampling temperature to use.
+            If not None, will override the temperature in the `generate()`
+            call. Defaults to None.
     """
 
     is_api: bool = True
 
-    def __init__(
-        self,
-        path: str,
-        max_seq_len: int = 2048,
-        query_per_second: int = 1,
-        retry: int = 2,
-        key: Union[str, List[str]] = 'ENV',
-        org: Optional[Union[str, List[str]]] = None,
-        meta_template: Optional[Dict] = None,
-        openai_api_base: str = 'https://api.openai.com/v1/chat/completions'
-    ):  # noqa
+    def __init__(self,
+                 path: str,
+                 max_seq_len: int = 2048,
+                 query_per_second: int = 1,
+                 retry: int = 2,
+                 key: Union[str, List[str]] = 'ENV',
+                 org: Optional[Union[str, List[str]]] = None,
+                 meta_template: Optional[Dict] = None,
+                 openai_api_base: str = OPENAI_API_BASE,
+                 temperature: Optional[float] = None):
+
         super().__init__(path=path,
                          max_seq_len=max_seq_len,
                          meta_template=meta_template,
@@ -62,6 +66,7 @@ class OpenAI(BaseAPIModel):
                          retry=retry)
         import tiktoken
         self.tiktoken = tiktoken
+        self.temperature = temperature
 
         if isinstance(key, str):
             self.keys = [os.getenv('OPENAI_API_KEY') if key == 'ENV' else key]
@@ -96,6 +101,9 @@ class OpenAI(BaseAPIModel):
         Returns:
             List[str]: A list of generated strings.
         """
+        if self.temperature is not None:
+            temperature = self.temperature
+
         with ThreadPoolExecutor() as executor:
             results = list(
                 executor.map(self._generate, inputs,