[diffusion] feat: Add Configurable Generator Device and Seed Support via API (#14366)

Co-authored-by: niehen6174 <niehen.6174@gmail.com>
Co-authored-by: Mick <mickjagger19@icloud.com>

python/sglang/multimodal_gen/configs/sample/sampling_params.py

@@ -101,6 +101,7 @@ class SamplingParams:
     # Batch info
     num_outputs_per_prompt: int = 1
     seed: int = 1024
+    generator_device: str = "cuda"  # Device for random generator: "cuda" or "cpu"
 
     # Original dimensions (before VAE scaling)
     num_frames: int = 125
@@ -393,6 +394,13 @@ class SamplingParams:
             default=SamplingParams.seed,
             help="Random seed for generation",
         )
+        parser.add_argument(
+            "--generator-device",
+            type=str,
+            default=SamplingParams.generator_device,
+            choices=["cuda", "cpu"],
+            help="Device for random generator (cuda or cpu). Default: cuda",
+        )
         parser.add_argument(
             "--num-frames",
             type=int,