Cleanup fa3.py

fa3.py

@@ -15,101 +15,4 @@ def flash_attn_func(q: torch.Tensor, k: torch.Tensor, v: torch.Tensor) -> torch.
 
 @flash_attn_func.register_fake
 def _(q, k, v, **kwargs):
-    # two outputs:
-    # 1. output: (batch, seq_len, num_heads, head_dim)
-    # 2. softmax_lse: (batch, num_heads, seq_len) with dtype=torch.float32
-    meta_q = torch.empty_like(q).contiguous()
-    return meta_q #, q.new_empty((q.size(0), q.size(2), q.size(1)), dtype=torch.float32)
-
-# Copied FusedFluxAttnProcessor2_0 but using flash v3 instead of SDPA
-class FlashFusedFluxAttnProcessor3_0:
-    """Attention processor used typically in processing the SD3-like self-attention projections."""
-
-    def __call__(
-        self,
-        attn,
-        hidden_states: torch.FloatTensor,
-        encoder_hidden_states: torch.FloatTensor | None = None,
-        attention_mask: torch.FloatTensor | None = None,
-        image_rotary_emb: torch.Tensor | None = None,
-    ) -> torch.FloatTensor:
-        batch_size, _, _ = hidden_states.shape if encoder_hidden_states is None else encoder_hidden_states.shape
-
-        # `sample` projections.
-        qkv = attn.to_qkv(hidden_states)
-        split_size = qkv.shape[-1] // 3
-        query, key, value = torch.split(qkv, split_size, dim=-1)
-
-        inner_dim = key.shape[-1]
-        head_dim = inner_dim // attn.heads
-
-        query = query.view(batch_size, -1, attn.heads, head_dim).transpose(1, 2)
-        key = key.view(batch_size, -1, attn.heads, head_dim).transpose(1, 2)
-        value = value.view(batch_size, -1, attn.heads, head_dim).transpose(1, 2)
-
-        if attn.norm_q is not None:
-            query = attn.norm_q(query)
-        if attn.norm_k is not None:
-            key = attn.norm_k(key)
-
-        # the attention in FluxSingleTransformerBlock does not use `encoder_hidden_states`
-        # `context` projections.
-        if encoder_hidden_states is not None:
-            encoder_qkv = attn.to_added_qkv(encoder_hidden_states)
-            split_size = encoder_qkv.shape[-1] // 3
-            (
-                encoder_hidden_states_query_proj,
-                encoder_hidden_states_key_proj,
-                encoder_hidden_states_value_proj,
-            ) = torch.split(encoder_qkv, split_size, dim=-1)
-
-            encoder_hidden_states_query_proj = encoder_hidden_states_query_proj.view(
-                batch_size, -1, attn.heads, head_dim
-            ).transpose(1, 2)
-            encoder_hidden_states_key_proj = encoder_hidden_states_key_proj.view(
-                batch_size, -1, attn.heads, head_dim
-            ).transpose(1, 2)
-            encoder_hidden_states_value_proj = encoder_hidden_states_value_proj.view(
-                batch_size, -1, attn.heads, head_dim
-            ).transpose(1, 2)
-
-            if attn.norm_added_q is not None:
-                encoder_hidden_states_query_proj = attn.norm_added_q(encoder_hidden_states_query_proj)
-            if attn.norm_added_k is not None:
-                encoder_hidden_states_key_proj = attn.norm_added_k(encoder_hidden_states_key_proj)
-
-            # attention
-            query = torch.cat([encoder_hidden_states_query_proj, query], dim=2)
-            key = torch.cat([encoder_hidden_states_key_proj, key], dim=2)
-            value = torch.cat([encoder_hidden_states_value_proj, value], dim=2)
-
-        if image_rotary_emb is not None:
-            from diffusers.models.embeddings import apply_rotary_emb
-
-            query = apply_rotary_emb(query, image_rotary_emb)
-            key = apply_rotary_emb(key, image_rotary_emb)
-
-        # NB: transposes are necessary to match expected SDPA input shape
-        hidden_states = flash_attn_func(
-            query.transpose(1, 2),
-            key.transpose(1, 2),
-            value.transpose(1, 2))[0].transpose(1, 2)
-
-        hidden_states = hidden_states.transpose(1, 2).reshape(batch_size, -1, attn.heads * head_dim)
-        hidden_states = hidden_states.to(query.dtype)
-
-        if encoder_hidden_states is not None:
-            encoder_hidden_states, hidden_states = (
-                hidden_states[:, : encoder_hidden_states.shape[1]],
-                hidden_states[:, encoder_hidden_states.shape[1] :],
-            )
-
-            # linear proj
-            hidden_states = attn.to_out[0](hidden_states)
-            # dropout
-            hidden_states = attn.to_out[1](hidden_states)
-            encoder_hidden_states = attn.to_add_out(encoder_hidden_states)
-
-            return hidden_states, encoder_hidden_states
-        else:
-            return hidden_states
+    return torch.empty_like(q).contiguous()