WIP: LCM

__init__.py

@@ -4,14 +4,19 @@ import sys
 sys.path.append(os.path.dirname(__file__))
 
 from coreml_suite.nodes import CoreMLLoaderUNet, CoreMLSampler, CoreMLModelAdapter
+from coreml_suite.lcm import CoreMLConverterLCM, CoreMLSamplerLCM
 
 NODE_CLASS_MAPPINGS = {
     "CoreMLUNetLoader": CoreMLLoaderUNet,
     "CoreMLSampler": CoreMLSampler,
     "CoreMLModelAdapter": CoreMLModelAdapter,
+    "CoreMLSamplerLCM": CoreMLSamplerLCM,
+    "CoreMLConverterLCM": CoreMLConverterLCM,
 }
 NODE_DISPLAY_NAME_MAPPINGS = {
     "CoreMLUNetLoader": "Load Core ML UNet",
     "CoreMLSampler": "Core ML Sampler",
     "CoreMLModelAdapter": "Core ML Adapter (Experimental)",
+    "CoreMLSamplerLCM": "Core ML LCM Sampler",
+    "CoreMLConverterLCM": "Convert LCM to Core ML",
 }

coreml_suite/lcm/__init__.py

@@ -0,0 +1,4 @@
+from lcm_sampler import CoreMLSamplerLCM
+from .nodes import CoreMLConverterLCM
+
+__all__ = ["CoreMLSamplerLCM", "CoreMLConverterLCM"]

coreml_suite/lcm/lcm_converter.py

@@ -0,0 +1,231 @@
+import os
+import shutil
+import logging
+import time
+import gc
+
+import numpy as np
+import torch
+from diffusers import UNet2DConditionModel
+from python_coreml_stable_diffusion.unet import (
+    UNet2DConditionModel as CoreMLUNet2DConditionModel,
+)
+from transformers import CLIPTextModel
+import coremltools as ct
+
+from folder_paths import get_folder_paths
+from coreml_suite.lcm.lcm_scheduler import LCMScheduler
+
+logging.basicConfig()
+logger = logging.getLogger(__name__)
+logger.setLevel(logging.DEBUG)
+
+MODEL_VERSION = "SimianLuo/LCM_Dreamshaper_v7"
+MODEL_NAME = MODEL_VERSION.split("/")[-1] + "_4k"
+
+import python_coreml_stable_diffusion.unet as unet
+
+unet.ATTENTION_IMPLEMENTATION_IN_EFFECT = unet.AttentionImplementations.SPLIT_EINSUM_V2
+
+
+def get_unets():
+    ref_unet = UNet2DConditionModel.from_pretrained(
+        MODEL_VERSION,
+        subfolder="unet",
+        device_map=None,
+        low_cpu_mem_usage=False,
+    )
+
+    ref_config = ref_unet.config
+
+    cml_unet = CoreMLUNet2DConditionModel().eval()
+    cml_unet.load_state_dict(ref_unet.state_dict(), strict=False)
+
+    del ref_unet
+    gc.collect()
+
+    return cml_unet, ref_config
+
+
+def get_encoder_hidden_states_shape(unet_config, batch_size):
+    text_encoder = CLIPTextModel.from_pretrained(
+        MODEL_VERSION, subfolder="text_encoder"
+    )
+
+    text_token_sequence_length = text_encoder.config.max_position_embeddings
+    hidden_size = (text_encoder.config.hidden_size,)
+
+    encoder_hidden_states_shape = (
+        batch_size,
+        unet_config.cross_attention_dim or hidden_size,
+        1,
+        text_token_sequence_length,
+    )
+
+    return encoder_hidden_states_shape
+
+
+def get_scheduler():
+    scheduler = LCMScheduler(
+        beta_start=0.00085,
+        beta_end=0.0120,
+        beta_schedule="scaled_linear",
+        prediction_type="epsilon",
+    )
+    scheduler.set_timesteps(50, 50)
+    return scheduler
+
+
+def get_coreml_inputs(sample_inputs):
+    coreml_sample_unet_inputs = {
+        k: v.numpy().astype(np.float16) for k, v in sample_inputs.items()
+    }
+    return [
+        ct.TensorType(
+            name=k,
+            shape=v.shape,
+            dtype=v.numpy().dtype if isinstance(v, torch.Tensor) else v.dtype,
+        )
+        for k, v in coreml_sample_unet_inputs.items()
+    ]
+
+
+def load_coreml_model(out_path):
+    logger.info(f"Loading model from {out_path}")
+
+    start = time.time()
+    coreml_model = ct.models.MLModel(out_path)
+    logger.info(f"Loading {out_path} took {time.time() - start:.1f} seconds")
+
+    return coreml_model
+
+
+def convert_to_coreml(
+    submodule_name, torchscript_module, sample_inputs, output_names, out_path
+):
+    if os.path.exists(out_path):
+        logger.info(f"Skipping export because {out_path} already exists")
+        coreml_model = load_coreml_model(out_path)
+    else:
+        logger.info(f"Converting {submodule_name} to CoreML..")
+        coreml_model = ct.convert(
+            torchscript_module,
+            convert_to="mlprogram",
+            minimum_deployment_target=ct.target.macOS13,
+            inputs=sample_inputs,
+            outputs=[
+                ct.TensorType(name=name, dtype=np.float32) for name in output_names
+            ],
+            skip_model_load=True,
+        )
+
+        del torchscript_module
+        gc.collect()
+
+    return coreml_model
+
+
+def get_out_path(submodule_name, model_name):
+    fname = f"{model_name}_{submodule_name}.mlpackage"
+    unet_path = get_folder_paths(submodule_name)[0]
+    out_path = os.path.join(unet_path, fname)
+    return out_path
+
+
+def compile_coreml_model(source_model_path, output_dir, final_name):
+    """Compiles Core ML models using the coremlcompiler utility from Xcode toolchain"""
+    target_path = os.path.join(output_dir, f"{final_name}.mlmodelc")
+    if os.path.exists(target_path):
+        logger.warning(f"Found existing compiled model at {target_path}! Skipping..")
+        return target_path
+
+    logger.info(f"Compiling {source_model_path}")
+    source_model_name = os.path.basename(os.path.splitext(source_model_path)[0])
+
+    os.system(f"xcrun coremlcompiler compile {source_model_path} {output_dir}")
+    compiled_output = os.path.join(output_dir, f"{source_model_name}.mlmodelc")
+    shutil.move(compiled_output, target_path)
+
+    return target_path
+
+
+def get_sample_input(batch_size, encoder_hidden_states_shape, sample_shape, scheduler):
+    sample_unet_inputs = dict(
+        [
+            ("sample", torch.rand(*sample_shape)),
+            (
+                "timestep",
+                torch.tensor([scheduler.timesteps[0].item()] * (batch_size)).to(
+                    torch.float32
+                ),
+            ),
+            ("encoder_hidden_states", torch.rand(*encoder_hidden_states_shape)),
+        ]
+    )
+    sample_unet_inputs_spec = {
+        k: (v.shape, v.dtype) for k, v in sample_unet_inputs.items()
+    }
+    return sample_unet_inputs, sample_unet_inputs_spec
+
+
+def convert(
+    out_path: str, batch_size: int = 1, sample_size: tuple[int, int] = (64, 64)
+):
+    coreml_unet, unet_config = get_unets()
+
+    sample_shape = (
+        batch_size,  # B
+        unet_config.in_channels,  # C
+        sample_size[0],  # H
+        sample_size[1],  # W
+    )
+
+    encoder_hidden_states_shape = get_encoder_hidden_states_shape(
+        unet_config, batch_size
+    )
+
+    scheduler = get_scheduler()
+
+    sample_inputs, sample_inputs_spec = get_sample_input(
+        batch_size, encoder_hidden_states_shape, sample_shape, scheduler
+    )
+
+    logger.info(f"Sample UNet inputs spec: {sample_inputs_spec}")
+    logger.info("JIT tracing..")
+    traced_unet = torch.jit.trace(coreml_unet, example_kwarg_inputs=sample_inputs)
+    logger.info("Done.")
+
+    coreml_sample_inputs = get_coreml_inputs(sample_inputs)
+
+    coreml_unet = convert_to_coreml(
+        "unet", traced_unet, coreml_sample_inputs, ["noise_pred"], out_path
+    )
+
+    del traced_unet
+    gc.collect()
+
+    coreml_unet.save(out_path)
+    logger.info(f"Saved unet into {out_path}")
+
+
+def compile_model(out_path, out_name):
+    # Compile the model
+    target_path = compile_coreml_model(
+        out_path, get_folder_paths("unet")[0], f"{out_name}_unet"
+    )
+    logger.info(f"Compiled {out_path} to {target_path}")
+    return target_path
+
+
+if __name__ == "__main__":
+    h = 512
+    w = 512
+    sample_size = (h // 8, w // 8)
+    batch_size = 4
+
+    out_name = f"{MODEL_NAME}_{w}x{h}_batch{batch_size}"
+
+    out_path = get_out_path("unet", f"{out_name}")
+    if not os.path.exists(out_path):
+        convert(out_path=out_path, sample_size=sample_size, batch_size=batch_size)
+    compile_model(out_path=out_path, out_name=out_name)

coreml_suite/lcm/lcm_pipeline.py

@@ -0,0 +1,290 @@
+import torch
+from diffusers import DiffusionPipeline, AutoencoderKL, UNet2DConditionModel
+from transformers import CLIPTokenizer, CLIPTextModel, CLIPImageProcessor
+from diffusers.pipelines.stable_diffusion import StableDiffusionPipelineOutput
+from diffusers.image_processor import VaeImageProcessor
+from typing import List, Optional, Union, Dict, Any
+from comfy.model_management import get_torch_device
+
+
+# from diffusers import logging
+# logger = logging.get_logger(__name__)  # pylint: disable=invalid-name
+
+
+class LatentConsistencyModelPipeline(DiffusionPipeline):
+    def __init__(
+        self,
+        vae: AutoencoderKL,
+        text_encoder: CLIPTextModel,
+        tokenizer: CLIPTokenizer,
+        unet: UNet2DConditionModel,
+        scheduler: None,
+        safety_checker: None,
+        feature_extractor: CLIPImageProcessor,
+    ):
+        super().__init__()
+
+        self.register_modules(
+            vae=vae,
+            text_encoder=text_encoder,
+            tokenizer=tokenizer,
+            unet=unet,
+            scheduler=scheduler,
+            safety_checker=safety_checker,
+            feature_extractor=feature_extractor,
+        )
+        self.vae_scale_factor = 2 ** (len(self.vae.config.block_out_channels) - 1)
+        self.image_processor = VaeImageProcessor(vae_scale_factor=self.vae_scale_factor)
+
+    def _encode_prompt(
+        self,
+        prompt,
+        device,
+        num_images_per_prompt,
+        prompt_embeds: None,
+    ):
+        r"""
+        Encodes the prompt into text encoder hidden states.
+
+        Args:
+            prompt (`str` or `List[str]`, *optional*):
+                prompt to be encoded
+            device: (`torch.device`):
+                torch device
+            num_images_per_prompt (`int`):
+                number of images that should be generated per prompt
+            prompt_embeds (`torch.FloatTensor`, *optional*):
+                Pre-generated text embeddings. Can be used to easily tweak text inputs, *e.g.* prompt weighting. If not
+                provided, text embeddings will be generated from `prompt` input argument.
+        """
+
+        if prompt is not None and isinstance(prompt, str):
+            batch_size = 1
+        elif prompt is not None and isinstance(prompt, list):
+            batch_size = len(prompt)
+        else:
+            batch_size = prompt_embeds.shape[0]
+
+        if prompt_embeds is None:
+            text_inputs = self.tokenizer(
+                prompt,
+                padding="max_length",
+                max_length=self.tokenizer.model_max_length,
+                truncation=True,
+                return_tensors="pt",
+            )
+            text_input_ids = text_inputs.input_ids
+            untruncated_ids = self.tokenizer(
+                prompt, padding="longest", return_tensors="pt"
+            ).input_ids
+
+            if untruncated_ids.shape[-1] >= text_input_ids.shape[
+                -1
+            ] and not torch.equal(text_input_ids, untruncated_ids):
+                removed_text = self.tokenizer.batch_decode(
+                    untruncated_ids[:, self.tokenizer.model_max_length - 1 : -1]
+                )
+                print(
+                    "The following part of your input was truncated because CLIP can only handle sequences up to"
+                    f" {self.tokenizer.model_max_length} tokens: {removed_text}"
+                )
+
+            if (
+                hasattr(self.text_encoder.config, "use_attention_mask")
+                and self.text_encoder.config.use_attention_mask
+            ):
+                attention_mask = text_inputs.attention_mask.to(device)
+            else:
+                attention_mask = None
+
+            prompt_embeds = self.text_encoder(
+                text_input_ids.to(device),
+                attention_mask=attention_mask,
+            )
+            prompt_embeds = prompt_embeds[0]
+
+        if self.text_encoder is not None:
+            prompt_embeds_dtype = self.text_encoder.dtype
+        elif self.unet is not None:
+            prompt_embeds_dtype = self.unet.dtype
+        else:
+            prompt_embeds_dtype = prompt_embeds.dtype
+
+        prompt_embeds = prompt_embeds.to(dtype=prompt_embeds_dtype, device=device)
+
+        bs_embed, seq_len, _ = prompt_embeds.shape
+        # duplicate text embeddings for each generation per prompt, using mps friendly method
+        prompt_embeds = prompt_embeds.repeat(1, num_images_per_prompt, 1)
+        prompt_embeds = prompt_embeds.view(
+            bs_embed * num_images_per_prompt, seq_len, -1
+        )
+
+        # Don't need to get uncond prompt embedding because of LCM Guided Distillation
+        return prompt_embeds
+
+    # ¯\_(ツ)_/¯
+    def run_safety_checker(self, image, device, dtype):
+        return image, None
+
+    def prepare_latents(
+        self,
+        batch_size,
+        num_channels_latents,
+        height,
+        width,
+        dtype,
+        device,
+        latents=None,
+    ):
+        shape = (
+            batch_size,
+            num_channels_latents,
+            height // self.vae_scale_factor,
+            width // self.vae_scale_factor,
+        )
+        if latents is None:
+            latents = torch.randn(shape, dtype=dtype).to(device)
+        else:
+            latents = latents.to(device)
+        # scale the initial noise by the standard deviation required by the scheduler
+        latents = latents * self.scheduler.init_noise_sigma
+        return latents
+
+    def get_w_embedding(self, w, embedding_dim=512, dtype=torch.float32):
+        """
+        see https://github.com/google-research/vdm/blob/dc27b98a554f65cdc654b800da5aa1846545d41b/model_vdm.py#L298
+        Args:
+        timesteps: torch.Tensor: generate embedding vectors at these timesteps
+        embedding_dim: int: dimension of the embeddings to generate
+        dtype: data type of the generated embeddings
+
+        Returns:
+        embedding vectors with shape `(len(timesteps), embedding_dim)`
+        """
+        assert len(w.shape) == 1
+        w = w * 1000.0
+
+        half_dim = embedding_dim // 2
+        emb = torch.log(torch.tensor(10000.0)) / (half_dim - 1)
+        emb = torch.exp(torch.arange(half_dim, dtype=dtype) * -emb)
+        emb = w.to(dtype)[:, None] * emb[None, :]
+        emb = torch.cat([torch.sin(emb), torch.cos(emb)], dim=1)
+        if embedding_dim % 2 == 1:  # zero pad
+            emb = torch.nn.functional.pad(emb, (0, 1))
+        assert emb.shape == (w.shape[0], embedding_dim)
+        return emb
+
+    @torch.no_grad()
+    def __call__(
+        self,
+        prompt: Union[str, List[str]] = None,
+        height: Optional[int] = 768,
+        width: Optional[int] = 768,
+        guidance_scale: float = 7.5,
+        num_images_per_prompt: Optional[int] = 1,
+        latents: Optional[torch.FloatTensor] = None,
+        num_inference_steps: int = 4,
+        lcm_origin_steps: int = 50,
+        prompt_embeds: Optional[torch.FloatTensor] = None,
+        output_type: Optional[str] = "pil",
+        return_dict: bool = True,
+        cross_attention_kwargs: Optional[Dict[str, Any]] = None,
+    ):
+        # 0. Default height and width to unet
+        height = height or self.unet.config.sample_size * self.vae_scale_factor
+        width = width or self.unet.config.sample_size * self.vae_scale_factor
+
+        # 2. Define call parameters
+        if prompt is not None and isinstance(prompt, str):
+            batch_size = 1
+        elif prompt is not None and isinstance(prompt, list):
+            batch_size = len(prompt)
+        else:
+            batch_size = prompt_embeds.shape[0]
+
+        device = get_torch_device()
+        # do_classifier_free_guidance = guidance_scale > 0.0  # In LCM Implementation:  cfg_noise = noise_cond + cfg_scale * (noise_cond - noise_uncond) , (cfg_scale > 0.0 using CFG)
+
+        # 3. Encode input prompt
+        prompt_embeds = self._encode_prompt(
+            prompt,
+            device,
+            num_images_per_prompt,
+            prompt_embeds=prompt_embeds,
+        )
+
+        # 4. Prepare timesteps
+        self.scheduler.set_timesteps(num_inference_steps, lcm_origin_steps)
+        timesteps = self.scheduler.timesteps
+
+        # 5. Prepare latent variable
+        num_channels_latents = self.unet.config.in_channels
+        latents = self.prepare_latents(
+            batch_size * num_images_per_prompt,
+            num_channels_latents,
+            height,
+            width,
+            prompt_embeds.dtype,
+            device,
+            latents,
+        )
+        bs = batch_size * num_images_per_prompt
+
+        # 6. Get Guidance Scale Embedding
+        w = torch.tensor(guidance_scale).repeat(bs)
+        w_embedding = self.get_w_embedding(w, embedding_dim=256).to(
+            device=device, dtype=latents.dtype
+        )
+
+        # 7. LCM MultiStep Sampling Loop:
+        with self.progress_bar(total=num_inference_steps) as progress_bar:
+            for i, t in enumerate(timesteps):
+                ts = torch.full((bs,), t, device=device, dtype=torch.long)
+                latents = latents.to(prompt_embeds.dtype)
+
+                # model prediction (v-prediction, eps, x)
+                model_pred = self.unet(
+                    latents,
+                    ts,
+                    timestep_cond=w_embedding,
+                    encoder_hidden_states=prompt_embeds,
+                    cross_attention_kwargs=cross_attention_kwargs,
+                    return_dict=False,
+                )[0]
+
+                # compute the previous noisy sample x_t -> x_t-1
+                latents, denoised = self.scheduler.step(
+                    model_pred, i, t, latents, return_dict=False
+                )
+
+                # # call the callback, if provided
+                # if i == len(timesteps) - 1:
+                progress_bar.update()
+
+        denoised = denoised.to(prompt_embeds.dtype)
+        if not output_type == "latent":
+            image = self.vae.decode(
+                denoised / self.vae.config.scaling_factor, return_dict=False
+            )[0]
+            image, has_nsfw_concept = self.run_safety_checker(
+                image, device, prompt_embeds.dtype
+            )
+        else:
+            image = denoised
+            has_nsfw_concept = None
+
+        if has_nsfw_concept is None:
+            do_denormalize = [True] * image.shape[0]
+        else:
+            do_denormalize = [not has_nsfw for has_nsfw in has_nsfw_concept]
+
+        image = self.image_processor.postprocess(
+            image, output_type=output_type, do_denormalize=do_denormalize
+        )
+
+        if not return_dict:
+            return (image, has_nsfw_concept)
+
+        return StableDiffusionPipelineOutput(
+            images=image, nsfw_content_detected=has_nsfw_concept
+        )

coreml_suite/lcm/lcm_sampler.py

@@ -0,0 +1,93 @@
+import os
+import time
+
+import torch
+
+from comfy.model_management import get_torch_device
+from coreml_suite.lcm.lcm_pipeline import LatentConsistencyModelPipeline
+from coreml_suite.lcm.lcm_scheduler import LCMScheduler
+
+
+class CoreMLSamplerLCM:
+    def __init__(self):
+        self.scheduler = LCMScheduler.from_pretrained(
+            os.path.join(os.path.dirname(__file__), "scheduler_config.json")
+        )
+        self.pipe = None
+
+    @classmethod
+    def INPUT_TYPES(s):
+        return {
+            "required": {
+                "model": ("MODEL",),
+                "seed": ("INT", {"default": 0, "min": 0, "max": 0xFFFFFFFFFFFFFFFF}),
+                "steps": ("INT", {"default": 4, "min": 1, "max": 10000}),
+                "cfg": (
+                    "FLOAT",
+                    {
+                        "default": 8.0,
+                        "min": 0.0,
+                        "max": 100.0,
+                        "step": 0.5,
+                        "round": 0.01,
+                    },
+                ),
+                "height": ("INT", {"default": 512, "min": 512, "max": 768}),
+                "width": ("INT", {"default": 512, "min": 512, "max": 768}),
+                "num_images": ("INT", {"default": 1, "min": 1, "max": 64}),
+                "use_fp16": ("BOOLEAN", {"default": True}),
+                "positive_prompt": ("STRING", {"multiline": True}),
+            }
+        }
+
+    RETURN_TYPES = ("IMAGE",)
+    FUNCTION = "sample"
+    CATEGORY = "sampling"
+
+    def sample(
+        self,
+        model,
+        seed,
+        steps,
+        cfg,
+        positive_prompt,
+        height,
+        width,
+        num_images,
+        use_fp16,
+    ):
+        if self.pipe is None:
+            self.pipe = LatentConsistencyModelPipeline.from_pretrained(
+                pretrained_model_name_or_path="SimianLuo/LCM_Dreamshaper_v7",
+                scheduler=self.scheduler,
+                safety_checker=None,
+            )
+
+            if use_fp16:
+                self.pipe.to(torch_device=get_torch_device(), torch_dtype=torch.float16)
+            else:
+                self.pipe.to(torch_device=get_torch_device(), torch_dtype=torch.float32)
+
+            coreml_unet = model.model
+            coreml_unet.config = self.pipe.unet.config
+
+            self.pipe.unet = coreml_unet
+
+        torch.manual_seed(seed)
+        start_time = time.time()
+
+        result = self.pipe(
+            prompt=positive_prompt,
+            width=width,
+            height=height,
+            guidance_scale=cfg,
+            num_inference_steps=steps,
+            num_images_per_prompt=num_images,
+            lcm_origin_steps=50,
+            output_type="np",
+        ).images
+
+        print("LCM inference time: ", time.time() - start_time, "seconds")
+        images_tensor = torch.from_numpy(result)
+
+        return (images_tensor,)

coreml_suite/lcm/lcm_scheduler.py

@@ -0,0 +1,524 @@
+# Copyright 2023 Stanford University Team and The HuggingFace Team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# 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.
+
+# DISCLAIMER: This code is strongly influenced by https://github.com/pesser/pytorch_diffusion
+# and https://github.com/hojonathanho/diffusion
+
+import math
+from dataclasses import dataclass
+from typing import List, Optional, Tuple, Union
+
+import numpy as np
+import torch
+
+from diffusers import ConfigMixin, SchedulerMixin
+from diffusers.configuration_utils import register_to_config
+from diffusers.utils import BaseOutput
+
+
+@dataclass
+# Copied from diffusers.schedulers.scheduling_ddpm.DDPMSchedulerOutput with DDPM->DDIM
+class LCMSchedulerOutput(BaseOutput):
+    """
+    Output class for the scheduler's `step` function output.
+
+    Args:
+        prev_sample (`torch.FloatTensor` of shape `(batch_size, num_channels, height, width)` for images):
+            Computed sample `(x_{t-1})` of previous timestep. `prev_sample` should be used as next model input in the
+            denoising loop.
+        pred_original_sample (`torch.FloatTensor` of shape `(batch_size, num_channels, height, width)` for images):
+            The predicted denoised sample `(x_{0})` based on the model output from the current timestep.
+            `pred_original_sample` can be used to preview progress or for guidance.
+    """
+
+    prev_sample: torch.FloatTensor
+    denoised: Optional[torch.FloatTensor] = None
+
+
+# Copied from diffusers.schedulers.scheduling_ddpm.betas_for_alpha_bar
+def betas_for_alpha_bar(
+    num_diffusion_timesteps,
+    max_beta=0.999,
+    alpha_transform_type="cosine",
+):
+    """
+    Create a beta schedule that discretizes the given alpha_t_bar function, which defines the cumulative product of
+    (1-beta) over time from t = [0,1].
+
+    Contains a function alpha_bar that takes an argument t and transforms it to the cumulative product of (1-beta) up
+    to that part of the diffusion process.
+
+
+    Args:
+        num_diffusion_timesteps (`int`): the number of betas to produce.
+        max_beta (`float`): the maximum beta to use; use values lower than 1 to
+                     prevent singularities.
+        alpha_transform_type (`str`, *optional*, default to `cosine`): the type of noise schedule for alpha_bar.
+                     Choose from `cosine` or `exp`
+
+    Returns:
+        betas (`np.ndarray`): the betas used by the scheduler to step the model outputs
+    """
+    if alpha_transform_type == "cosine":
+
+        def alpha_bar_fn(t):
+            return math.cos((t + 0.008) / 1.008 * math.pi / 2) ** 2
+
+    elif alpha_transform_type == "exp":
+
+        def alpha_bar_fn(t):
+            return math.exp(t * -12.0)
+
+    else:
+        raise ValueError(f"Unsupported alpha_tranform_type: {alpha_transform_type}")
+
+    betas = []
+    for i in range(num_diffusion_timesteps):
+        t1 = i / num_diffusion_timesteps
+        t2 = (i + 1) / num_diffusion_timesteps
+        betas.append(min(1 - alpha_bar_fn(t2) / alpha_bar_fn(t1), max_beta))
+    return torch.tensor(betas, dtype=torch.float32)
+
+
+def rescale_zero_terminal_snr(betas):
+    """
+    Rescales betas to have zero terminal SNR Based on https://arxiv.org/pdf/2305.08891.pdf (Algorithm 1)
+
+
+    Args:
+        betas (`torch.FloatTensor`):
+            the betas that the scheduler is being initialized with.
+
+    Returns:
+        `torch.FloatTensor`: rescaled betas with zero terminal SNR
+    """
+    # Convert betas to alphas_bar_sqrt
+    alphas = 1.0 - betas
+    alphas_cumprod = torch.cumprod(alphas, dim=0)
+    alphas_bar_sqrt = alphas_cumprod.sqrt()
+
+    # Store old values.
+    alphas_bar_sqrt_0 = alphas_bar_sqrt[0].clone()
+    alphas_bar_sqrt_T = alphas_bar_sqrt[-1].clone()
+
+    # Shift so the last timestep is zero.
+    alphas_bar_sqrt -= alphas_bar_sqrt_T
+
+    # Scale so the first timestep is back to the old value.
+    alphas_bar_sqrt *= alphas_bar_sqrt_0 / (alphas_bar_sqrt_0 - alphas_bar_sqrt_T)
+
+    # Convert alphas_bar_sqrt to betas
+    alphas_bar = alphas_bar_sqrt**2  # Revert sqrt
+    alphas = alphas_bar[1:] / alphas_bar[:-1]  # Revert cumprod
+    alphas = torch.cat([alphas_bar[0:1], alphas])
+    betas = 1 - alphas
+
+    return betas
+
+
+class LCMScheduler(SchedulerMixin, ConfigMixin):
+    """
+    `LCMScheduler` extends the denoising procedure introduced in denoising diffusion probabilistic models (DDPMs) with
+    non-Markovian guidance.
+
+    This model inherits from [`SchedulerMixin`] and [`ConfigMixin`]. Check the superclass documentation for the generic
+    methods the library implements for all schedulers such as loading and saving.
+
+    Args:
+        num_train_timesteps (`int`, defaults to 1000):
+            The number of diffusion steps to train the model.
+        beta_start (`float`, defaults to 0.0001):
+            The starting `beta` value of inference.
+        beta_end (`float`, defaults to 0.02):
+            The final `beta` value.
+        beta_schedule (`str`, defaults to `"linear"`):
+            The beta schedule, a mapping from a beta range to a sequence of betas for stepping the model. Choose from
+            `linear`, `scaled_linear`, or `squaredcos_cap_v2`.
+        trained_betas (`np.ndarray`, *optional*):
+            Pass an array of betas directly to the constructor to bypass `beta_start` and `beta_end`.
+        clip_sample (`bool`, defaults to `True`):
+            Clip the predicted sample for numerical stability.
+        clip_sample_range (`float`, defaults to 1.0):
+            The maximum magnitude for sample clipping. Valid only when `clip_sample=True`.
+        set_alpha_to_one (`bool`, defaults to `True`):
+            Each diffusion step uses the alphas product value at that step and at the previous one. For the final step
+            there is no previous alpha. When this option is `True` the previous alpha product is fixed to `1`,
+            otherwise it uses the alpha value at step 0.
+        steps_offset (`int`, defaults to 0):
+            An offset added to the inference steps. You can use a combination of `offset=1` and
+            `set_alpha_to_one=False` to make the last step use step 0 for the previous alpha product like in Stable
+            Diffusion.
+        prediction_type (`str`, defaults to `epsilon`, *optional*):
+            Prediction type of the scheduler function; can be `epsilon` (predicts the noise of the diffusion process),
+            `sample` (directly predicts the noisy sample`) or `v_prediction` (see section 2.4 of [Imagen
+            Video](https://imagen.research.google/video/paper.pdf) paper).
+        thresholding (`bool`, defaults to `False`):
+            Whether to use the "dynamic thresholding" method. This is unsuitable for latent-space diffusion models such
+            as Stable Diffusion.
+        dynamic_thresholding_ratio (`float`, defaults to 0.995):
+            The ratio for the dynamic thresholding method. Valid only when `thresholding=True`.
+        sample_max_value (`float`, defaults to 1.0):
+            The threshold value for dynamic thresholding. Valid only when `thresholding=True`.
+        timestep_spacing (`str`, defaults to `"leading"`):
+            The way the timesteps should be scaled. Refer to Table 2 of the [Common Diffusion Noise Schedules and
+            Sample Steps are Flawed](https://huggingface.co/papers/2305.08891) for more information.
+        rescale_betas_zero_snr (`bool`, defaults to `False`):
+            Whether to rescale the betas to have zero terminal SNR. This enables the model to generate very bright and
+            dark samples instead of limiting it to samples with medium brightness. Loosely related to
+            [`--offset_noise`](https://github.com/huggingface/diffusers/blob/74fd735eb073eb1d774b1ab4154a0876eb82f055/examples/dreambooth/train_dreambooth.py#L506).
+    """
+
+    # _compatibles = [e.name for e in KarrasDiffusionSchedulers]
+    order = 1
+
+    @register_to_config
+    def __init__(
+        self,
+        num_train_timesteps: int = 1000,
+        beta_start: float = 0.0001,
+        beta_end: float = 0.02,
+        beta_schedule: str = "linear",
+        trained_betas: Optional[Union[np.ndarray, List[float]]] = None,
+        clip_sample: bool = True,
+        set_alpha_to_one: bool = True,
+        steps_offset: int = 0,
+        prediction_type: str = "epsilon",
+        thresholding: bool = False,
+        dynamic_thresholding_ratio: float = 0.995,
+        clip_sample_range: float = 1.0,
+        sample_max_value: float = 1.0,
+        timestep_spacing: str = "leading",
+        rescale_betas_zero_snr: bool = False,
+    ):
+        if trained_betas is not None:
+            self.betas = torch.tensor(trained_betas, dtype=torch.float32)
+        elif beta_schedule == "linear":
+            self.betas = torch.linspace(
+                beta_start, beta_end, num_train_timesteps, dtype=torch.float32
+            )
+        elif beta_schedule == "scaled_linear":
+            # this schedule is very specific to the latent diffusion model.
+            self.betas = (
+                torch.linspace(
+                    beta_start**0.5,
+                    beta_end**0.5,
+                    num_train_timesteps,
+                    dtype=torch.float32,
+                )
+                ** 2
+            )
+        elif beta_schedule == "squaredcos_cap_v2":
+            # Glide cosine schedule
+            self.betas = betas_for_alpha_bar(num_train_timesteps)
+        else:
+            raise NotImplementedError(
+                f"{beta_schedule} does is not implemented for {self.__class__}"
+            )
+
+        # Rescale for zero SNR
+        if rescale_betas_zero_snr:
+            self.betas = rescale_zero_terminal_snr(self.betas)
+
+        self.alphas = 1.0 - self.betas
+        self.alphas_cumprod = torch.cumprod(self.alphas, dim=0)
+
+        # At every step in ddim, we are looking into the previous alphas_cumprod
+        # For the final step, there is no previous alphas_cumprod because we are already at 0
+        # `set_alpha_to_one` decides whether we set this parameter simply to one or
+        # whether we use the final alpha of the "non-previous" one.
+        self.final_alpha_cumprod = (
+            torch.tensor(1.0) if set_alpha_to_one else self.alphas_cumprod[0]
+        )
+
+        # standard deviation of the initial noise distribution
+        self.init_noise_sigma = 1.0
+
+        # setable values
+        self.num_inference_steps = None
+        self.timesteps = torch.from_numpy(
+            np.arange(0, num_train_timesteps)[::-1].copy().astype(np.int64)
+        )
+
+    def scale_model_input(
+        self, sample: torch.FloatTensor, timestep: Optional[int] = None
+    ) -> torch.FloatTensor:
+        """
+        Ensures interchangeability with schedulers that need to scale the denoising model input depending on the
+        current timestep.
+
+        Args:
+            sample (`torch.FloatTensor`):
+                The input sample.
+            timestep (`int`, *optional*):
+                The current timestep in the diffusion chain.
+
+        Returns:
+            `torch.FloatTensor`:
+                A scaled input sample.
+        """
+        return sample
+
+    def _get_variance(self, timestep, prev_timestep):
+        alpha_prod_t = self.alphas_cumprod[timestep]
+        alpha_prod_t_prev = (
+            self.alphas_cumprod[prev_timestep]
+            if prev_timestep >= 0
+            else self.final_alpha_cumprod
+        )
+        beta_prod_t = 1 - alpha_prod_t
+        beta_prod_t_prev = 1 - alpha_prod_t_prev
+
+        variance = (beta_prod_t_prev / beta_prod_t) * (
+            1 - alpha_prod_t / alpha_prod_t_prev
+        )
+
+        return variance
+
+    # Copied from diffusers.schedulers.scheduling_ddpm.DDPMScheduler._threshold_sample
+    def _threshold_sample(self, sample: torch.FloatTensor) -> torch.FloatTensor:
+        """
+        "Dynamic thresholding: At each sampling step we set s to a certain percentile absolute pixel value in xt0 (the
+        prediction of x_0 at timestep t), and if s > 1, then we threshold xt0 to the range [-s, s] and then divide by
+        s. Dynamic thresholding pushes saturated pixels (those near -1 and 1) inwards, thereby actively preventing
+        pixels from saturation at each step. We find that dynamic thresholding results in significantly better
+        photorealism as well as better image-text alignment, especially when using very large guidance weights."
+
+        https://arxiv.org/abs/2205.11487
+        """
+        dtype = sample.dtype
+        batch_size, channels, height, width = sample.shape
+
+        if dtype not in (torch.float32, torch.float64):
+            # upcast for quantile calculation, and clamp not implemented for cpu half
+            sample = sample.float()
+
+        # Flatten sample for doing quantile calculation along each image
+        sample = sample.reshape(batch_size, channels * height * width)
+
+        abs_sample = sample.abs()  # "a certain percentile absolute pixel value"
+
+        s = torch.quantile(abs_sample, self.config.dynamic_thresholding_ratio, dim=1)
+        s = torch.clamp(
+            s, min=1, max=self.config.sample_max_value
+        )  # When clamped to min=1, equivalent to standard clipping to [-1, 1]
+
+        # (batch_size, 1) because clamp will broadcast along dim=0
+        s = s.unsqueeze(1)
+        # "we threshold xt0 to the range [-s, s] and then divide by s"
+        sample = torch.clamp(sample, -s, s) / s
+
+        sample = sample.reshape(batch_size, channels, height, width)
+        sample = sample.to(dtype)
+
+        return sample
+
+    def set_timesteps(
+        self,
+        num_inference_steps: int,
+        lcm_origin_steps: int,
+        device: Union[str, torch.device] = None,
+    ):
+        """
+        Sets the discrete timesteps used for the diffusion chain (to be run before inference).
+
+        Args:
+            num_inference_steps (`int`):
+                The number of diffusion steps used when generating samples with a pre-trained model.
+        """
+
+        if num_inference_steps > self.config.num_train_timesteps:
+            raise ValueError(
+                f"`num_inference_steps`: {num_inference_steps} cannot be larger than `self.config.train_timesteps`:"
+                f" {self.config.num_train_timesteps} as the unet model trained with this scheduler can only handle"
+                f" maximal {self.config.num_train_timesteps} timesteps."
+            )
+
+        self.num_inference_steps = num_inference_steps
+
+        # LCM Timesteps Setting:  # Linear Spacing
+        c = self.config.num_train_timesteps // lcm_origin_steps
+        lcm_origin_timesteps = (
+            np.asarray(list(range(1, lcm_origin_steps + 1))) * c - 1
+        )  # LCM Training  Steps Schedule
+        skipping_step = len(lcm_origin_timesteps) // num_inference_steps
+        # LCM Inference Steps Schedule
+        timesteps = lcm_origin_timesteps[::-skipping_step][:num_inference_steps]
+
+        self.timesteps = torch.from_numpy(timesteps.copy()).to(device)
+
+    def get_scalings_for_boundary_condition_discrete(self, t):
+        self.sigma_data = 0.5  # Default: 0.5
+
+        # By dividing 0.1: This is almost a delta function at t=0.
+        c_skip = self.sigma_data**2 / ((t / 0.1) ** 2 + self.sigma_data**2)
+        c_out = (t / 0.1) / ((t / 0.1) ** 2 + self.sigma_data**2) ** 0.5
+        return c_skip, c_out
+
+    def step(
+        self,
+        model_output: torch.FloatTensor,
+        timeindex: int,
+        timestep: int,
+        sample: torch.FloatTensor,
+        eta: float = 0.0,
+        use_clipped_model_output: bool = False,
+        generator=None,
+        variance_noise: Optional[torch.FloatTensor] = None,
+        return_dict: bool = True,
+    ) -> Union[LCMSchedulerOutput, Tuple]:
+        """
+        Predict the sample from the previous timestep by reversing the SDE. This function propagates the diffusion
+        process from the learned model outputs (most often the predicted noise).
+
+        Args:
+            model_output (`torch.FloatTensor`):
+                The direct output from learned diffusion model.
+            timestep (`float`):
+                The current discrete timestep in the diffusion chain.
+            sample (`torch.FloatTensor`):
+                A current instance of a sample created by the diffusion process.
+            eta (`float`):
+                The weight of noise for added noise in diffusion step.
+            use_clipped_model_output (`bool`, defaults to `False`):
+                If `True`, computes "corrected" `model_output` from the clipped predicted original sample. Necessary
+                because predicted original sample is clipped to [-1, 1] when `self.config.clip_sample` is `True`. If no
+                clipping has happened, "corrected" `model_output` would coincide with the one provided as input and
+                `use_clipped_model_output` has no effect.
+            generator (`torch.Generator`, *optional*):
+                A random number generator.
+            variance_noise (`torch.FloatTensor`):
+                Alternative to generating noise with `generator` by directly providing the noise for the variance
+                itself. Useful for methods such as [`CycleDiffusion`].
+            return_dict (`bool`, *optional*, defaults to `True`):
+                Whether or not to return a [`~schedulers.scheduling_lcm.LCMSchedulerOutput`] or `tuple`.
+
+        Returns:
+            [`~schedulers.scheduling_utils.LCMSchedulerOutput`] or `tuple`:
+                If return_dict is `True`, [`~schedulers.scheduling_lcm.LCMSchedulerOutput`] is returned, otherwise a
+                tuple is returned where the first element is the sample tensor.
+
+        """
+        if self.num_inference_steps is None:
+            raise ValueError(
+                "Number of inference steps is 'None', you need to run 'set_timesteps' after creating the scheduler"
+            )
+
+        # 1. get previous step value
+        prev_timeindex = timeindex + 1
+        if prev_timeindex < len(self.timesteps):
+            prev_timestep = self.timesteps[prev_timeindex]
+        else:
+            prev_timestep = timestep
+
+        # 2. compute alphas, betas
+        alpha_prod_t = self.alphas_cumprod[timestep]
+        alpha_prod_t_prev = (
+            self.alphas_cumprod[prev_timestep]
+            if prev_timestep >= 0
+            else self.final_alpha_cumprod
+        )
+
+        beta_prod_t = 1 - alpha_prod_t
+        beta_prod_t_prev = 1 - alpha_prod_t_prev
+
+        # 3. Get scalings for boundary conditions
+        c_skip, c_out = self.get_scalings_for_boundary_condition_discrete(timestep)
+
+        # 4. Different Parameterization:
+        parameterization = self.config.prediction_type
+
+        if parameterization == "epsilon":  # noise-prediction
+            pred_x0 = (sample - beta_prod_t.sqrt() * model_output) / alpha_prod_t.sqrt()
+
+        elif parameterization == "sample":  # x-prediction
+            pred_x0 = model_output
+
+        elif parameterization == "v_prediction":  # v-prediction
+            pred_x0 = alpha_prod_t.sqrt() * sample - beta_prod_t.sqrt() * model_output
+
+        # 4. Denoise model output using boundary conditions
+        denoised = c_out * pred_x0 + c_skip * sample
+
+        # 5. Sample z ~ N(0, I), For MultiStep Inference
+        # Noise is not used for one-step sampling.
+        if len(self.timesteps) > 1:
+            noise = torch.randn(model_output.shape).to(model_output.device)
+            prev_sample = (
+                alpha_prod_t_prev.sqrt() * denoised + beta_prod_t_prev.sqrt() * noise
+            )
+        else:
+            prev_sample = denoised
+
+        if not return_dict:
+            return (prev_sample, denoised)
+
+        return LCMSchedulerOutput(prev_sample=prev_sample, denoised=denoised)
+
+    # Copied from diffusers.schedulers.scheduling_ddpm.DDPMScheduler.add_noise
+
+    def add_noise(
+        self,
+        original_samples: torch.FloatTensor,
+        noise: torch.FloatTensor,
+        timesteps: torch.IntTensor,
+    ) -> torch.FloatTensor:
+        # Make sure alphas_cumprod and timestep have same device and dtype as original_samples
+        alphas_cumprod = self.alphas_cumprod.to(
+            device=original_samples.device, dtype=original_samples.dtype
+        )
+        timesteps = timesteps.to(original_samples.device)
+
+        sqrt_alpha_prod = alphas_cumprod[timesteps] ** 0.5
+        sqrt_alpha_prod = sqrt_alpha_prod.flatten()
+        while len(sqrt_alpha_prod.shape) < len(original_samples.shape):
+            sqrt_alpha_prod = sqrt_alpha_prod.unsqueeze(-1)
+
+        sqrt_one_minus_alpha_prod = (1 - alphas_cumprod[timesteps]) ** 0.5
+        sqrt_one_minus_alpha_prod = sqrt_one_minus_alpha_prod.flatten()
+        while len(sqrt_one_minus_alpha_prod.shape) < len(original_samples.shape):
+            sqrt_one_minus_alpha_prod = sqrt_one_minus_alpha_prod.unsqueeze(-1)
+
+        noisy_samples = (
+            sqrt_alpha_prod * original_samples + sqrt_one_minus_alpha_prod * noise
+        )
+        return noisy_samples
+
+    # Copied from diffusers.schedulers.scheduling_ddpm.DDPMScheduler.get_velocity
+    def get_velocity(
+        self,
+        sample: torch.FloatTensor,
+        noise: torch.FloatTensor,
+        timesteps: torch.IntTensor,
+    ) -> torch.FloatTensor:
+        # Make sure alphas_cumprod and timestep have same device and dtype as sample
+        alphas_cumprod = self.alphas_cumprod.to(
+            device=sample.device, dtype=sample.dtype
+        )
+        timesteps = timesteps.to(sample.device)
+
+        sqrt_alpha_prod = alphas_cumprod[timesteps] ** 0.5
+        sqrt_alpha_prod = sqrt_alpha_prod.flatten()
+        while len(sqrt_alpha_prod.shape) < len(sample.shape):
+            sqrt_alpha_prod = sqrt_alpha_prod.unsqueeze(-1)
+
+        sqrt_one_minus_alpha_prod = (1 - alphas_cumprod[timesteps]) ** 0.5
+        sqrt_one_minus_alpha_prod = sqrt_one_minus_alpha_prod.flatten()
+        while len(sqrt_one_minus_alpha_prod.shape) < len(sample.shape):
+            sqrt_one_minus_alpha_prod = sqrt_one_minus_alpha_prod.unsqueeze(-1)
+
+        velocity = sqrt_alpha_prod * noise - sqrt_one_minus_alpha_prod * sample
+        return velocity
+
+    def __len__(self):
+        return self.config.num_train_timesteps

coreml_suite/lcm/nodes.py

@@ -0,0 +1,52 @@
+import os
+
+from coreml_suite.lcm import lcm_converter
+
+
+class CoreMLConverterLCM:
+    """Converts a LCM model to Core ML."""
+
+    RETURN_TYPES = ("COMBO",)
+    RETURN_NAMES = ("model_name",)
+    FUNCTION = "convert"
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "height": ("INT", {"default": 512, "min": 512, "max": 768, "step": 8}),
+                "width": ("INT", {"default": 512, "min": 512, "max": 768, "step": 8}),
+                "batch_size": ("INT", {"default": 4, "min": 1, "max": 64}),
+            }
+        }
+
+    def convert(self, height, width, batch_size):
+        """Converts a LCM model to Core ML.
+
+        Args:
+            height (int): Height of the target image.
+            width (int): Width of the target image.
+            batch_size (int): Batch size.
+
+        Returns:
+            MODEL: The converted Core ML model.
+
+        The converted model is also saved to "models/unet" directory and
+        can be loaded with the "LCMCoreMLLoaderUNet" node.
+        """
+        h = height
+        w = width
+        sample_size = (h // 8, w // 8)
+        batch_size = batch_size
+
+        out_name = f"{lcm_converter.MODEL_NAME}_{w}x{h}_batch{batch_size}"
+
+        out_path = lcm_converter.get_out_path("unet", f"{out_name}")
+
+        if not os.path.exists(out_path):
+            lcm_converter.convert(
+                out_path=out_path, sample_size=sample_size, batch_size=batch_size
+            )
+        target_path = lcm_converter.compile_model(out_path=out_path, out_name=out_name)
+
+        return (target_path.split("/")[-1],)

coreml_suite/lcm/scheduler_config.json

@@ -0,0 +1,19 @@
+{
+  "_class_name": "LCMScheduler",
+  "_diffusers_version": "0.22.0.dev0",
+  "beta_end": 0.012,
+  "beta_schedule": "scaled_linear",
+  "beta_start": 0.00085,
+  "clip_sample": true,
+  "clip_sample_range": 1.0,
+  "dynamic_thresholding_ratio": 0.995,
+  "num_train_timesteps": 1000,
+  "prediction_type": "epsilon",
+  "rescale_betas_zero_snr": false,
+  "sample_max_value": 1.0,
+  "set_alpha_to_one": true,
+  "steps_offset": 0,
+  "thresholding": false,
+  "timestep_spacing": "leading",
+  "trained_betas": null
+}

coreml_suite/models.py

@@ -30,14 +30,14 @@ class CoreMLModelWrapper(BaseModel):
         self.diffusion_model = coreml_model
 
     def apply_model(
-        self,
-        x,
-        t,
-        c_concat=None,
-        c_crossattn=None,
-        c_adm=None,
-        control=None,
-        transformer_options={},
+            self,
+            x,
+            t,
+            c_concat=None,
+            c_crossattn=None,
+            c_adm=None,
+            control=None,
+            transformer_options={},
     ):
         chunked_in = self.chunk_inputs(x, t, c_crossattn, control)
         chunked_out = [
@@ -53,9 +53,6 @@ class CoreMLModelWrapper(BaseModel):
     def _apply_model(self, x, t, c_concat=None, c_crossattn=None, c_adm=None,
                     control=None, transformer_options={}):
         model_input_kwargs = self.prepare_inputs(x, t, c_crossattn, control)
-        residual_kwargs = extract_residual_kwargs(self.diffusion_model,
-                                                  control)
-        model_input_kwargs |= residual_kwargs
 
         np_out = self.diffusion_model(**model_input_kwargs)["noise_pred"]
         return torch.from_numpy(np_out).to(x.device)
@@ -112,4 +109,7 @@ class CoreMLModelWrapperLCM(CoreMLModelWrapper):
         model_input_kwargs = self.prepare_inputs(x, t, c_crossattn, control)
 
         np_out = self.diffusion_model(**model_input_kwargs)["noise_pred"]
-        return torch.from_numpy(np_out).to(x.device)
+        return (torch.from_numpy(np_out).to(x.device),)
+
+    def __call__(self, latents, t, encoder_hidden_states, **kwargs):
+        return self.apply_model(latents, t, c_crossattn=encoder_hidden_states, **kwargs)