Add support for OpenAI API : offline batch(file) processing (#699)

Co-authored-by: hnyls2002 <hnyls2002@gmail.com>

python/sglang/srt/managers/io_struct.py

@@ -79,8 +79,26 @@ class GenerateReqInput:
             if self.top_logprobs_num is None:
                 self.top_logprobs_num = 0
         else:
-
-            parallel_sample_num = self.sampling_params.get("n", 1)
+            parallel_sample_num_list = []
+            if isinstance(self.sampling_params, dict):
+                parallel_sample_num = self.sampling_params.get("n", 1)
+            elif isinstance(self.sampling_params, list):
+                for sp in self.sampling_params:
+                    parallel_sample_num = sp.get("n", 1)
+                    parallel_sample_num_list.append(parallel_sample_num)
+                parallel_sample_num = max(parallel_sample_num_list)
+                all_equal = all(
+                    element == parallel_sample_num
+                    for element in parallel_sample_num_list
+                )
+                if parallel_sample_num > 1 and (not all_equal):
+                    ## TODO cope with the case that the parallel_sample_num is different for different samples
+                    raise ValueError(
+                        "The parallel_sample_num should be the same for all samples in sample params."
+                    )
+            else:
+                parallel_sample_num = 1
+            self.parallel_sample_num = parallel_sample_num
 
             if parallel_sample_num != 1:
                 # parallel sampling +1 represents the original prefill stage