[SD-XL] Flax implementation

src/diffusers/__init__.py

@@ -270,6 +270,7 @@
         FlaxStableDiffusionImg2ImgPipeline,
         FlaxStableDiffusionInpaintPipeline,
         FlaxStableDiffusionPipeline,
+        FlaxStableDiffusionXLPipeline
     )
 
 try:

src/diffusers/models/modeling_flax_pytorch_utils.py

@@ -42,9 +42,20 @@ def rename_key(key):
 # and https://github.com/patil-suraj/stable-diffusion-jax/blob/main/stable_diffusion_jax/convert_diffusers_to_jax.py
 def rename_key_and_reshape_tensor(pt_tuple_key, pt_tensor, random_flax_state_dict):
     """Rename PT weight names to corresponding Flax weight names and reshape tensor if necessary"""
-
     # conv norm or layer norm
     renamed_pt_tuple_key = pt_tuple_key[:-1] + ("scale",)
+
+    # rename attention layers
+    if len(pt_tuple_key) > 1:
+        for rename_from, rename_to in (('to_out_0', 'proj_attn'), ('to_k', 'key'), ('to_v', 'value'), ('to_q', 'query')):
+            if pt_tuple_key[-2] == rename_from:
+                weight_name = pt_tuple_key[-1]
+                weight_name = 'kernel' if weight_name == 'weight' else weight_name
+                renamed_pt_tuple_key = pt_tuple_key[:-2] + (rename_to, weight_name)
+                if renamed_pt_tuple_key in random_flax_state_dict:
+                    assert random_flax_state_dict[renamed_pt_tuple_key].shape == pt_tensor.T.shape
+                    return renamed_pt_tuple_key, pt_tensor.T
+
     if (
         any("norm" in str_ for str_ in pt_tuple_key)
         and (pt_tuple_key[-1] == "bias")

src/diffusers/models/unet_2d_blocks_flax.py

@@ -52,6 +52,7 @@ class FlaxCrossAttnDownBlock2D(nn.Module):
     only_cross_attention: bool = False
     use_memory_efficient_attention: bool = False
     dtype: jnp.dtype = jnp.float32
+    transformer_layers_per_block: int = 1
 
     def setup(self):
         resnets = []
@@ -72,7 +73,7 @@ def setup(self):
                 in_channels=self.out_channels,
                 n_heads=self.num_attention_heads,
                 d_head=self.out_channels // self.num_attention_heads,
-                depth=1,
+                depth=self.transformer_layers_per_block,
                 use_linear_projection=self.use_linear_projection,
                 only_cross_attention=self.only_cross_attention,
                 use_memory_efficient_attention=self.use_memory_efficient_attention,
@@ -192,6 +193,7 @@ class FlaxCrossAttnUpBlock2D(nn.Module):
     only_cross_attention: bool = False
     use_memory_efficient_attention: bool = False
     dtype: jnp.dtype = jnp.float32
+    transformer_layers_per_block: int = 1
 
     def setup(self):
         resnets = []
@@ -213,7 +215,7 @@ def setup(self):
                 in_channels=self.out_channels,
                 n_heads=self.num_attention_heads,
                 d_head=self.out_channels // self.num_attention_heads,
-                depth=1,
+                depth=self.transformer_layers_per_block,
                 use_linear_projection=self.use_linear_projection,
                 only_cross_attention=self.only_cross_attention,
                 use_memory_efficient_attention=self.use_memory_efficient_attention,
@@ -331,6 +333,7 @@ class FlaxUNetMidBlock2DCrossAttn(nn.Module):
     use_linear_projection: bool = False
     use_memory_efficient_attention: bool = False
     dtype: jnp.dtype = jnp.float32
+    transformer_layers_per_block: int = 1
 
     def setup(self):
         # there is always at least one resnet
@@ -350,7 +353,7 @@ def setup(self):
                 in_channels=self.in_channels,
                 n_heads=self.num_attention_heads,
                 d_head=self.in_channels // self.num_attention_heads,
-                depth=1,
+                depth=self.transformer_layers_per_block,
                 use_linear_projection=self.use_linear_projection,
                 use_memory_efficient_attention=self.use_memory_efficient_attention,
                 dtype=self.dtype,

src/diffusers/models/unet_2d_condition.py

@@ -205,7 +205,7 @@ def __init__(
         class_embeddings_concat: bool = False,
         mid_block_only_cross_attention: Optional[bool] = None,
         cross_attention_norm: Optional[str] = None,
-        addition_embed_type_num_heads=64,
+        addition_embed_type_num_heads = 64,
     ):
         super().__init__()
 
@@ -848,7 +848,6 @@ def forward(
             time_ids = added_cond_kwargs.get("time_ids")
             time_embeds = self.add_time_proj(time_ids.flatten())
             time_embeds = time_embeds.reshape((text_embeds.shape[0], -1))
-
             add_embeds = torch.concat([text_embeds, time_embeds], dim=-1)
             add_embeds = add_embeds.to(emb.dtype)
             aug_emb = self.add_embedding(add_embeds)

src/diffusers/models/unet_2d_condition_flax.py

@@ -11,7 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from typing import Optional, Tuple, Union
+from typing import Optional, Tuple, Union, Dict
 
 import flax
 import flax.linen as nn
@@ -116,6 +116,11 @@ class FlaxUNet2DConditionModel(nn.Module, FlaxModelMixin, ConfigMixin):
     flip_sin_to_cos: bool = True
     freq_shift: int = 0
     use_memory_efficient_attention: bool = False
+    transformer_layers_per_block: Union[int, Tuple[int]] = 1
+    addition_embed_type: Optional[str] = None
+    addition_time_embed_dim: Optional[int] = None
+    addition_embed_type_num_heads: int = 64
+    projection_class_embeddings_input_dim: Optional[int] = None
 
     def init_weights(self, rng: jax.random.KeyArray) -> FrozenDict:
         # init input tensors
@@ -127,7 +132,13 @@ def init_weights(self, rng: jax.random.KeyArray) -> FrozenDict:
         params_rng, dropout_rng = jax.random.split(rng)
         rngs = {"params": params_rng, "dropout": dropout_rng}
 
-        return self.init(rngs, sample, timesteps, encoder_hidden_states)["params"]
+        added_cond_kwargs = None
+        if self.addition_embed_type == 'text_time':
+            added_cond_kwargs = {
+                    'text_embeds': jnp.zeros((1, 1280), dtype=jnp.float32),   # TODO: This should be set based on config
+                    'time_ids': jnp.zeros((1, 6), dtype=jnp.float32)
+                    }
+        return self.init(rngs, sample, timesteps, encoder_hidden_states, added_cond_kwargs)["params"]
 
     def setup(self):
         block_out_channels = self.block_out_channels
@@ -168,6 +179,22 @@ def setup(self):
         if isinstance(num_attention_heads, int):
             num_attention_heads = (num_attention_heads,) * len(self.down_block_types)
 
+        # transformer layers per block
+        transformer_layers_per_block = self.transformer_layers_per_block
+        if isinstance(transformer_layers_per_block, int):
+            transformer_layers_per_block = [transformer_layers_per_block] * len(self.down_block_types)
+
+        # addition embed types
+        if self.addition_embed_type is None:
+            self.add_embedding = None
+        elif self.addition_embed_type == 'text_time':
+            if self.addition_time_embed_dim is None:
+                raise ValueError(f'addition_embed_type {self.addition_embed_type} requires `addition_time_embed_dim` to not be None')
+            self.add_time_proj = FlaxTimesteps(self.addition_time_embed_dim, self.flip_sin_to_cos, self.freq_shift)
+            self.add_embedding = FlaxTimestepEmbedding(time_embed_dim, dtype=self.dtype)
+        else:
+            raise ValueError(f"addition_embed_type: {self.addition_embed_type} must be None or `text_time`.")
+
         # down
         down_blocks = []
         output_channel = block_out_channels[0]
@@ -182,6 +209,7 @@ def setup(self):
                     out_channels=output_channel,
                     dropout=self.dropout,
                     num_layers=self.layers_per_block,
+                    transformer_layers_per_block=transformer_layers_per_block[i],
                     num_attention_heads=num_attention_heads[i],
                     add_downsample=not is_final_block,
                     use_linear_projection=self.use_linear_projection,
@@ -207,6 +235,7 @@ def setup(self):
             in_channels=block_out_channels[-1],
             dropout=self.dropout,
             num_attention_heads=num_attention_heads[-1],
+            transformer_layers_per_block=transformer_layers_per_block[-1],
             use_linear_projection=self.use_linear_projection,
             use_memory_efficient_attention=self.use_memory_efficient_attention,
             dtype=self.dtype,
@@ -218,6 +247,7 @@ def setup(self):
         reversed_num_attention_heads = list(reversed(num_attention_heads))
         only_cross_attention = list(reversed(only_cross_attention))
         output_channel = reversed_block_out_channels[0]
+        reversed_transformer_layers_per_block = list(reversed(transformer_layers_per_block))
         for i, up_block_type in enumerate(self.up_block_types):
             prev_output_channel = output_channel
             output_channel = reversed_block_out_channels[i]
@@ -231,6 +261,7 @@ def setup(self):
                     out_channels=output_channel,
                     prev_output_channel=prev_output_channel,
                     num_layers=self.layers_per_block + 1,
+                    transformer_layers_per_block=reversed_transformer_layers_per_block[i],
                     num_attention_heads=reversed_num_attention_heads[i],
                     add_upsample=not is_final_block,
                     dropout=self.dropout,
@@ -269,6 +300,7 @@ def __call__(
         sample,
         timesteps,
         encoder_hidden_states,
+        added_cond_kwargs: Optional[Union[Dict, FrozenDict]] = None,
         down_block_additional_residuals=None,
         mid_block_additional_residual=None,
         return_dict: bool = True,
@@ -300,6 +332,29 @@ def __call__(
         t_emb = self.time_proj(timesteps)
         t_emb = self.time_embedding(t_emb)
 
+        # additional embeddings
+        aug_emb = None
+        if self.addition_embed_type == 'text_time':
+            if added_cond_kwargs is None:
+                raise ValueError(f'Need to provide argument `added_cond_kwargs` for {self.__class__} when using `addition_embed_type={self.addition_embed_type}`')
+            text_embeds = added_cond_kwargs.get("text_embeds")
+            if text_embeds is None:
+                raise ValueError(
+                    f"{self.__class__} has the config param `addition_embed_type` set to 'text_time' which requires the keyword argument `text_embeds` to be passed in `added_cond_kwargs`"
+                )
+            time_ids = added_cond_kwargs.get("time_ids")
+            if time_ids is None:
+                raise ValueError(
+                    f"{self.__class__} has the config param `addition_embed_type` set to 'text_time' which requires the keyword argument `time_ids` to be passed in `added_cond_kwargs`"
+                )
+            # compute time embeds
+            time_embeds = self.add_time_proj(jnp.ravel(time_ids))   # (1, 6) => (6,) => (6, 256)
+            time_embeds = jnp.reshape(time_embeds, (text_embeds.shape[0], -1))
+            add_embeds = jnp.concatenate([text_embeds, time_embeds], axis=-1)
+            aug_emb = self.add_embedding(add_embeds)
+
+        t_emb = t_emb + aug_emb if aug_emb is not None else t_emb
+
         # 2. pre-process
         sample = jnp.transpose(sample, (0, 2, 3, 1))
         sample = self.conv_in(sample)

src/diffusers/pipelines/__init__.py

@@ -173,6 +173,9 @@
         FlaxStableDiffusionInpaintPipeline,
         FlaxStableDiffusionPipeline,
     )
+    from .stable_diffusion_xl import (
+        FlaxStableDiffusionXLPipeline,
+    )
 try:
     if not (is_transformers_available() and is_torch_available() and is_note_seq_available()):
         raise OptionalDependencyNotAvailable()

src/diffusers/pipelines/stable_diffusion_xl/__init__.py

@@ -4,7 +4,13 @@
 import numpy as np
 import PIL
 
-from ...utils import BaseOutput, is_invisible_watermark_available, is_torch_available, is_transformers_available
+from ...utils import (
+    BaseOutput,
+    is_invisible_watermark_available,
+    is_torch_available,
+    is_transformers_available,
+    is_flax_available,
+)
 
 
 @dataclass
@@ -24,3 +30,8 @@ class StableDiffusionXLPipelineOutput(BaseOutput):
 if is_transformers_available() and is_torch_available() and is_invisible_watermark_available():
     from .pipeline_stable_diffusion_xl import StableDiffusionXLPipeline
     from .pipeline_stable_diffusion_xl_img2img import StableDiffusionXLImg2ImgPipeline
+
+
+if is_flax_available():
+    from .pipeline_flax_stable_diffusion_xl import FlaxStableDiffusionXLPipeline
+