[Feature] support top_k_top_p sampling (#2753)

* support top_k_top_p sampling

* fix

* add api param

* add api para

* fix

* fix

* fix

* fix

* fix

* fix

* fix

fastdeploy/engine/sampling_params.py

@@ -52,6 +52,7 @@ class SamplingParams:
             the model more random. Zero means greedy sampling.
         top_p: Float that controls the cumulative probability of the top tokens
             to consider. Must be in [0, 1]. Set to 1 to consider all tokens.
+        top_k: Int that controls the number of top tokens to consider. Must be a positive integer.
         seed: Random seed to use for the generation.
         stop: list of strings that stop the generation when they are generated.
             The returned output will not contain the stop strings.
@@ -81,7 +82,8 @@ class SamplingParams:
     frequency_penalty: float = None
     repetition_penalty: float = None
     temperature: float = None
-    top_p: float = None
+    top_p: float = 1.0
+    top_k: int = 0
     seed: Optional[int] = None
     stop: Optional[Union[str, List[str]]] = None
     stop_token_ids: Optional[Union[List[List[int]], List[int]]] = None
@@ -111,6 +113,7 @@ class SamplingParams:
                       repetition_penalty,
                       temperature,
                       top_p,
+                      top_k,
                       seed=None,
                       stop=None,
                       stop_token_ids=None,
@@ -129,7 +132,8 @@ class SamplingParams:
                    repetition_penalty=repetition_penalty
                    if repetition_penalty is not None else 1.0,
                    temperature=temperature if temperature is not None else 1.0,
-                   top_p=top_p if top_p is not None else 0.7,
+                   top_p=top_p if top_p is not None else 1.0,
+                   top_k=top_k if top_k is not None else 0,
                    seed=seed,
                    stop=stop,
                    stop_token_ids=stop_token_ids,