[Diffusion] Delete useless _ulysses_input_split func (#19786)

python/sglang/multimodal_gen/runtime/layers/usp.py

@@ -9,7 +9,6 @@ from torch.distributed.tensor.experimental._attention import _cp_options
 
 from sglang.multimodal_gen.runtime.distributed.parallel_state import (
     get_sp_group,
-    get_ulysses_parallel_rank,
     get_ulysses_parallel_world_size,
 )
 from sglang.srt.utils.common import torch_release
@@ -159,22 +158,6 @@ def _usp_output_all_to_all(x: torch.Tensor, head_dim: int = 1) -> torch.Tensor:
     return x
 
 
-def _ulysses_input_split(x: torch.Tensor, dim: int = 1) -> torch.Tensor:
-    world_size = get_ulysses_parallel_world_size()
-    if world_size <= 1:
-        return x
-    rank = get_ulysses_parallel_rank()
-    assert x.ndim == 4, f"x must have 4 dimensions, got {x.ndim}"
-
-    dim_to_split_size = x.shape[dim]
-
-    assert (
-        dim_to_split_size % world_size == 0
-    ), f"The size of dimension {dim} ({dim_to_split_size}) must be divisible by world_size ({world_size})"
-
-    return torch.tensor_split(x, world_size, dim=dim)[rank].contiguous()
-
-
 def ring_attn(
     query: torch.Tensor,
     key: torch.Tensor,