refactor 3d rope for cogvideox (huggingface#9269)

* refactor 3d rope

* repeat -> expand

Author: yiyixuxu

src/diffusers/models/embeddings.py

@@ -391,15 +391,16 @@ def get_3d_rotary_pos_embed(
         The size of the temporal dimension.
     theta (`float`):
         Scaling factor for frequency computation.
-    use_real (`bool`):
-        If True, return real part and imaginary part separately. Otherwise, return complex numbers.
 
     Returns:
         `torch.Tensor`: positional embedding with shape `(temporal_size * grid_size[0] * grid_size[1], embed_dim/2)`.
     """
+    if use_real is not True:
+        raise ValueError(" `use_real = False` is not currently supported for get_3d_rotary_pos_embed")
     start, stop = crops_coords
-    grid_h = np.linspace(start[0], stop[0], grid_size[0], endpoint=False, dtype=np.float32)
-    grid_w = np.linspace(start[1], stop[1], grid_size[1], endpoint=False, dtype=np.float32)
+    grid_size_h, grid_size_w = grid_size
+    grid_h = np.linspace(start[0], stop[0], grid_size_h, endpoint=False, dtype=np.float32)
+    grid_w = np.linspace(start[1], stop[1], grid_size_w, endpoint=False, dtype=np.float32)
     grid_t = np.linspace(0, temporal_size, temporal_size, endpoint=False, dtype=np.float32)
 
     # Compute dimensions for each axis
@@ -408,54 +409,37 @@ def get_3d_rotary_pos_embed(
     dim_w = embed_dim // 8 * 3
 
     # Temporal frequencies
-    freqs_t = 1.0 / (theta ** (torch.arange(0, dim_t, 2).float() / dim_t))
-    grid_t = torch.from_numpy(grid_t).float()
-    freqs_t = torch.einsum("n , f -> n f", grid_t, freqs_t)
-    freqs_t = freqs_t.repeat_interleave(2, dim=-1)
-
+    freqs_t = get_1d_rotary_pos_embed(dim_t, grid_t, use_real=True)
     # Spatial frequencies for height and width
-    freqs_h = 1.0 / (theta ** (torch.arange(0, dim_h, 2).float() / dim_h))
-    freqs_w = 1.0 / (theta ** (torch.arange(0, dim_w, 2).float() / dim_w))
-    grid_h = torch.from_numpy(grid_h).float()
-    grid_w = torch.from_numpy(grid_w).float()
-    freqs_h = torch.einsum("n , f -> n f", grid_h, freqs_h)
-    freqs_w = torch.einsum("n , f -> n f", grid_w, freqs_w)
-    freqs_h = freqs_h.repeat_interleave(2, dim=-1)
-    freqs_w = freqs_w.repeat_interleave(2, dim=-1)
-
-    # Broadcast and concatenate tensors along specified dimension
-    def broadcast(tensors, dim=-1):
-        num_tensors = len(tensors)
-        shape_lens = {len(t.shape) for t in tensors}
-        assert len(shape_lens) == 1, "tensors must all have the same number of dimensions"
-        shape_len = list(shape_lens)[0]
-        dim = (dim + shape_len) if dim < 0 else dim
-        dims = list(zip(*(list(t.shape) for t in tensors)))
-        expandable_dims = [(i, val) for i, val in enumerate(dims) if i != dim]
-        assert all(
-            [*(len(set(t[1])) <= 2 for t in expandable_dims)]
-        ), "invalid dimensions for broadcastable concatenation"
-        max_dims = [(t[0], max(t[1])) for t in expandable_dims]
-        expanded_dims = [(t[0], (t[1],) * num_tensors) for t in max_dims]
-        expanded_dims.insert(dim, (dim, dims[dim]))
-        expandable_shapes = list(zip(*(t[1] for t in expanded_dims)))
-        tensors = [t[0].expand(*t[1]) for t in zip(tensors, expandable_shapes)]
-        return torch.cat(tensors, dim=dim)
-
-    freqs = broadcast((freqs_t[:, None, None, :], freqs_h[None, :, None, :], freqs_w[None, None, :, :]), dim=-1)
-
-    t, h, w, d = freqs.shape
-    freqs = freqs.view(t * h * w, d)
-
-    # Generate sine and cosine components
-    sin = freqs.sin()
-    cos = freqs.cos()
-
-    if use_real:
-        return cos, sin
-    else:
-        freqs_cis = torch.polar(torch.ones_like(freqs), freqs)
-        return freqs_cis
+    freqs_h = get_1d_rotary_pos_embed(dim_h, grid_h, use_real=True)
+    freqs_w = get_1d_rotary_pos_embed(dim_w, grid_w, use_real=True)
+
+    # BroadCast and concatenate temporal and spaial frequencie (height and width) into a 3d tensor
+    def combine_time_height_width(freqs_t, freqs_h, freqs_w):
+        freqs_t = freqs_t[:, None, None, :].expand(
+            -1, grid_size_h, grid_size_w, -1
+        )  # temporal_size, grid_size_h, grid_size_w, dim_t
+        freqs_h = freqs_h[None, :, None, :].expand(
+            temporal_size, -1, grid_size_w, -1
+        )  # temporal_size, grid_size_h, grid_size_2, dim_h
+        freqs_w = freqs_w[None, None, :, :].expand(
+            temporal_size, grid_size_h, -1, -1
+        )  # temporal_size, grid_size_h, grid_size_2, dim_w
+
+        freqs = torch.cat(
+            [freqs_t, freqs_h, freqs_w], dim=-1
+        )  # temporal_size, grid_size_h, grid_size_w, (dim_t + dim_h + dim_w)
+        freqs = freqs.view(
+            temporal_size * grid_size_h * grid_size_w, -1
+        )  # (temporal_size * grid_size_h * grid_size_w), (dim_t + dim_h + dim_w)
+        return freqs
+
+    t_cos, t_sin = freqs_t  # both t_cos and t_sin has shape: temporal_size, dim_t
+    h_cos, h_sin = freqs_h  # both h_cos and h_sin has shape: grid_size_h, dim_h
+    w_cos, w_sin = freqs_w  # both w_cos and w_sin has shape: grid_size_w, dim_w
+    cos = combine_time_height_width(t_cos, h_cos, w_cos)
+    sin = combine_time_height_width(t_sin, h_sin, w_sin)
+    return cos, sin
 
 
 def get_2d_rotary_pos_embed(embed_dim, crops_coords, grid_size, use_real=True):

src/diffusers/pipelines/cogvideo/pipeline_cogvideox.py

@@ -463,7 +463,6 @@ def _prepare_rotary_positional_embeddings(
             crops_coords=grid_crops_coords,
             grid_size=(grid_height, grid_width),
             temporal_size=num_frames,
-            use_real=True,
         )
 
         freqs_cos = freqs_cos.to(device=device)