API: Add min_tokens

Bans the EOS token until the generation reaches a minimum length. This will not prevent the model from otherwise ending the generation early by outputting other stop conditions.

common/sampling.py

@@ -18,6 +18,11 @@ class BaseSamplerRequest(BaseModel):
         examples=[150],
     )
 
+    min_tokens: Optional[int] = Field(
+        default_factory=lambda: get_default_sampler_value("min_tokens", 0),
+        examples=[0],
+    )
+
     generate_window: Optional[int] = Field(
         default_factory=lambda: get_default_sampler_value("generate_window"),
         examples=[512],
@@ -260,6 +265,7 @@ class BaseSamplerRequest(BaseModel):
 
         gen_params = {
             "max_tokens": self.max_tokens,
+            "min_tokens": self.min_tokens,
             "generate_window": self.generate_window,
             "stop": self.stop,
             "add_bos_token": self.add_bos_token,