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vllm-omni/vllm_omni/diffusion/attention/layer.py
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2025-12-05 10:46:20 +00:00

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Python

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
import torch
import torch.nn as nn
from vllm_omni.diffusion.attention.backends.abstract import (
AttentionMetadata,
)
from vllm_omni.diffusion.attention.selector import get_attn_backend
class Attention(nn.Module):
def __init__(
self,
num_heads: int,
head_size: int,
causal: bool,
softmax_scale: float,
num_kv_heads: int | None = None,
prefix: str = "",
):
super().__init__()
self.attn_backend = get_attn_backend(-1)
self.attn_impl_cls = self.attn_backend.get_impl_cls()
self.attention = self.attn_impl_cls(
num_heads=num_heads,
head_size=head_size,
softmax_scale=softmax_scale,
causal=causal,
num_kv_heads=num_kv_heads,
)
def forward(
self,
query: torch.Tensor,
key: torch.Tensor,
value: torch.Tensor,
attn_metadata: AttentionMetadata = None,
) -> torch.Tensor:
# shape: (batch_size, seq_len, num_heads, head_size)
attn_output = self.attention.forward(query, key, value, attn_metadata)
return attn_output