mmedit.models.editors.controlnet.controlnet 源代码
# Copyright (c) OpenMMLab. All rights reserved.
from logging import WARNING
from typing import Dict, List, Optional, Tuple, Union
import numpy as np
import torch
import torch.nn as nn
import torch.nn.functional as F
from mmengine import print_log
from mmengine.model import is_model_wrapper
from mmengine.optim import OptimWrapperDict
from PIL import Image
from torch import Tensor
from tqdm import tqdm
from mmedit.models.utils import build_module
from mmedit.registry import MODELS
from mmedit.structures import EditDataSample
from mmedit.utils.typing import SampleList
from ..stable_diffusion import StableDiffusion
from .controlnet_utils import change_base_model
@MODELS.register_module()
[文档]class ControlStableDiffusion(StableDiffusion):
"""Implementation of `ControlNet with Stable Diffusion.
<https://arxiv.org/abs/2302.05543>`_ (ControlNet).
Args:
vae (Union[dict, nn.Module]): The config or module for VAE model.
text_encoder (Union[dict, nn.Module]): The config or module for text
encoder.
tokenizer (str): The **name** for CLIP tokenizer.
unet (Union[dict, nn.Module]): The config or module for Unet model.
controlnet (Union[dict, nn.Module]): The config or module for
ControlNet.
schedule (Union[dict, nn.Module]): The config or module for diffusion
scheduler.
test_scheduler (Union[dict, nn.Module], optional): The config or
module for diffusion scheduler in test stage (`self.infer`). If not
passed, will use the same scheduler as `schedule`. Defaults to
None.
enable_xformers (bool, optional): Whether to use xformers.
Defaults to True.
data_preprocessor (dict, optional): The pre-process config of
:class:`BaseDataPreprocessor`. Defaults to
dict(type='EditDataPreprocessor').
init_cfg (dict, optional): The weight initialized config for
:class:`BaseModule`. Defaults to None/
"""
def __init__(self,
vae: ModelType,
text_encoder: ModelType,
tokenizer: str,
unet: ModelType,
controlnet: ModelType,
scheduler: ModelType,
test_scheduler: Optional[ModelType] = None,
enable_xformers: bool = True,
data_preprocessor=dict(type='EditDataPreprocessor'),
init_cfg: Optional[dict] = None):
super().__init__(vae, text_encoder, tokenizer, unet, scheduler,
test_scheduler, enable_xformers, data_preprocessor,
init_cfg)
self.controlnet = build_module(controlnet, MODELS)
self.vae.requires_grad_(False)
self.text_encoder.requires_grad_(False)
self.unet.requires_grad_(False)
[文档] def init_weights(self):
"""Initialize the weights. Noted that this function will only be called
at train. If you want to inference with a different unet model, you can
call this function manually or use
`mmedit.models.editors.controlnet.controlnet_utils.change_base_model`
to convert the weight of ControlNet manually.
Example:
>>> 1. init controlnet from unet
>>> init_cfg = dict(type='init_from_unet')
>>> 2. switch controlnet weight from unet
>>> # base model is not defined, use `runwayml/stable-diffusion-v1-5`
>>> # as default
>>> init_cfg = dict(type='convert_from_unet')
>>> # base model is defined
>>> init_cfg = dict(
>>> type='convert_from_unet',
>>> base_model=dict(
>>> type='UNet2DConditionModel',
>>> from_pretrained='REPO_ID',
>>> subfolder='unet'))
"""
if self.init_cfg is not None:
init_type = self.init_cfg.get('type', None)
else:
init_type = None
if init_type == 'init_from_unet':
# fetch module
if is_model_wrapper(self.controlnet):
controlnet = self.controlnet.module
else:
controlnet = self.controlnet
if is_model_wrapper(self.unet):
unet = self.unet.module
else:
unet = self.unet
if controlnet._from_pretrained is not None:
print_log(
'ControlNet has initialized from pretrained '
f'weight \'{controlnet._from_pretrained}\'.'
' Re-initialize ControlNet from Unet.', 'current', WARNING)
# copy weight
log_template = 'Initialize weight ControlNet from Unet: {}'
for n, p in unet.named_parameters():
if n in controlnet.state_dict():
print_log(log_template.format(n), 'current')
controlnet.state_dict()[n].copy_(p.data)
# check zero_conv
zero_conv_blocks = controlnet.controlnet_down_blocks
for n, p in zero_conv_blocks.named_parameters():
if not (p == 0).all():
print_log(f'{n} in ControlNet is not initialized with '
'zero. Set to zero manually.')
p.data.zero_()
elif init_type == 'convert_from_unet':
# fetch module
if is_model_wrapper(self.controlnet):
controlnet = self.controlnet.module
else:
controlnet = self.controlnet
if is_model_wrapper(self.unet):
unet = self.unet.module
else:
unet = self.unet
# use sd-v15 as base model by default
base_model_default_cfg = dict(
type='UNet2DConditionModel',
from_pretrained='runwayml/stable-diffusion-v1-5',
subfolder='unet')
base_model_cfg = self.init_cfg.get('base_model',
base_model_default_cfg)
base_model = MODELS.build(base_model_cfg)
change_base_model(controlnet, unet, base_model)
else:
assert init_type is None, (
'Only support \'init_from_unet\', \'convert_from_unet\' or '
f'None. But receive {init_type}.')
[文档] def train_step(self, data: dict,
optim_wrapper: OptimWrapperDict) -> Dict[str, Tensor]:
"""Train step for ControlNet model.
Args:
data (dict): Data sampled from dataloader.
optim_wrapper (OptimWrapperDict): OptimWrapperDict instance
contains OptimWrapper of generator and discriminator.
Returns:
Dict[str, torch.Tensor]: A ``dict`` of tensor for logging.
"""
data = self.data_preprocessor(data)
inputs, data_samples = data['inputs'], data['data_samples']
optimizer = optim_wrapper['controlnet']
with optimizer.optim_context(self.controlnet):
target = inputs['target']
control = (inputs['source'] + 1) / 2 # [-1, 1] -> [0, 1]
prompt = data_samples.prompt
num_batches = target.shape[0]
latents = self.vae.encode(target).latent_dist.sample()
latents = latents * self.vae.config.scaling_factor
noise = torch.randn_like(latents)
timesteps = torch.randint(
0,
self.scheduler.num_train_timesteps, (num_batches, ),
device=self.device)
timesteps = timesteps.long()
noisy_latents = self.scheduler.add_noise(latents, noise, timesteps)
input_ids = self.tokenizer(
prompt,
max_length=self.tokenizer.model_max_length,
return_tensors='pt',
padding='max_length',
truncation=True)['input_ids'].to(self.device)
encoder_hidden_states = self.text_encoder(input_ids)[0]
if self.scheduler.config.prediction_type == 'epsilon':
gt = noise
elif self.scheduler.config.prediction_type == 'v_prediction':
gt = self.scheduler.get_velocity(latents, noise, timesteps)
else:
raise ValueError('Unknown prediction type '
f'{self.scheduler.config.prediction_type}')
# forward control
down_block_res_samples, mid_block_res_sample = self.controlnet(
noisy_latents,
timesteps,
encoder_hidden_states=encoder_hidden_states,
controlnet_cond=control,
return_dict=False,
)
# Predict the noise residual and compute loss
model_output = self.unet(
noisy_latents,
timesteps,
encoder_hidden_states=encoder_hidden_states,
down_block_additional_residuals=down_block_res_samples,
mid_block_additional_residual=mid_block_res_sample)
model_pred = model_output['sample']
loss = F.mse_loss(model_pred.float(), gt.float(), reduction='mean')
optimizer.update_params(loss)
return dict(loss=loss)
[文档] def val_step(self, data: dict) -> SampleList:
"""Gets the generated image of given data. Calls
``self.data_preprocessor`` and ``self.infer`` in order. Return the
generated results which will be passed to evaluator or visualizer.
Args:
data (dict or tuple or list): Data sampled from dataset.
Returns:
SampleList: Generated image or image dict.
"""
data = self.data_preprocessor(data)
prompt = data['data_samples'].prompt
control = data['inputs']['source']
output = self.infer(
prompt, control=((control + 1) / 2), return_type='tensor')
samples = output['samples']
samples = self.data_preprocessor.destruct(
samples, data['data_samples'], key='target')
control = self.data_preprocessor.destruct(
control, data['data_samples'], key='source')
data_sample = EditDataSample(
fake_img=samples,
control=control,
prompt=data['data_samples'].prompt)
data_sample_list = data_sample.split()
return data_sample_list
[文档] def test_step(self, data: dict) -> SampleList:
"""Gets the generated image of given data. Calls
``self.data_preprocessor`` and ``self.infer`` in order. Return the
generated results which will be passed to evaluator or visualizer.
Args:
data (dict or tuple or list): Data sampled from dataset.
Returns:
SampleList: Generated image or image dict.
"""
data = self.data_preprocessor(data)
prompt = data['data_samples'].prompt
control = data['inputs']['source']
output = self.infer(
prompt, control=((control + 1) / 2), return_type='tensor')
samples = output['samples']
samples = self.data_preprocessor.destruct(
samples, data['data_samples'], key='target')
control = self.data_preprocessor.destruct(
control, data['data_samples'], key='source')
data_sample = EditDataSample(
fake_img=samples,
control=control,
prompt=data['data_samples'].prompt)
data_sample_list = data_sample.split()
return data_sample_list
# NOTE: maybe we should do this in a controlnet preprocessor
@staticmethod
[文档] def prepare_control(image: Tuple[Image.Image, List[Image.Image], Tensor,
List[Tensor]], width: int, height: int,
batch_size: int, num_images_per_prompt: int,
device: str, dtype: str) -> Tensor:
"""A helper function to prepare single control images.
Args:
image (Tuple[Image.Image, List[Image.Image], Tensor, List[Tensor]]): # noqa
The input image for control.
batch_size (int): The batch size of the control. The control will
be repeated for `batch_size` times.
num_images_per_prompt (int): The number images generate for one
prompt.
device (str): The device of the control.
dtype (str): The dtype of the control.
Returns:
Tensor: The control in torch.tensor.
"""
if not isinstance(image, torch.Tensor):
if isinstance(image, Image.Image):
image = [image]
if isinstance(image[0], Image.Image):
image = [
img.resize((width, height), resample=Image.LANCZOS)
for img in image
]
image = [np.array(img)[None, :] for img in image]
image = np.concatenate(image, axis=0)
image = np.array(image).astype(np.float32) / 255.0
image = image.transpose(0, 3, 1, 2)
image = torch.from_numpy(image)
elif isinstance(image[0], torch.Tensor):
image = torch.cat(image, dim=0)
image_batch_size = image.shape[0]
if image_batch_size == 1:
repeat_by = batch_size
else:
# image batch size is the same as prompt batch size
repeat_by = num_images_per_prompt
image = image.repeat_interleave(repeat_by, dim=0)
image = image.to(device=device, dtype=dtype)
return image
@torch.no_grad()
[文档] def infer(self,
prompt: Union[str, List[str]],
height: Optional[int] = None,
width: Optional[int] = None,
control: Optional[Union[str, np.ndarray, torch.Tensor]] = None,
controlnet_conditioning_scale: float = 1.0,
num_inference_steps: int = 20,
guidance_scale: float = 7.5,
negative_prompt: Optional[Union[str, List[str]]] = None,
num_images_per_prompt: Optional[int] = 1,
eta: float = 0.0,
generator: Optional[torch.Generator] = None,
latents: Optional[torch.FloatTensor] = None,
return_type='image',
show_progress=True):
"""Function invoked when calling the pipeline for generation.
Args:
prompt (str or List[str]): The prompt or prompts to guide
the image generation.
height (int, Optional): The height in pixels of the generated
image. If not passed, the height will be
`self.unet_sample_size * self.vae_scale_factor` Defaults
to None.
width (int, Optional): The width in pixels of the generated image.
If not passed, the width will be
`self.unet_sample_size * self.vae_scale_factor` Defaults
to None.
num_inference_steps (int): The number of denoising steps.
More denoising steps usually lead to a higher quality image at
the expense of slower inference. Defaults to 50.
guidance_scale (float): Guidance scale as defined in Classifier-
Free Diffusion Guidance (https://arxiv.org/abs/2207.12598).
Defaults to 7.5
negative_prompt (str or List[str], optional): The prompt or
prompts not to guide the image generation. Ignored when not
using guidance (i.e., ignored if `guidance_scale` is less
than 1). Defaults to None.
num_images_per_prompt (int): The number of images to generate
per prompt. Defaults to 1.
eta (float): Corresponds to parameter eta (η) in the DDIM paper:
https://arxiv.org/abs/2010.02502. Only applies to
DDIMScheduler, will be ignored for others. Defaults to 0.0.
generator (torch.Generator, optional): A torch generator to make
generation deterministic. Defaults to None.
latents (torch.FloatTensor, optional): Pre-generated noisy latents,
sampled from a Gaussian distribution, to be used as inputs for
image generation. Can be used to tweak the same generation with
different prompts. If not provided, a latents tensor will be
generated by sampling using the supplied random `generator`.
Defaults to None.
return_type (str): The return type of the inference results.
Supported types are 'image', 'numpy', 'tensor'. If 'image'
is passed, a list of PIL images will be returned. If 'numpy'
is passed, a numpy array with shape [N, C, H, W] will be
returned, and the value range will be same as decoder's
output range. If 'tensor' is passed, the decoder's output
will be returned. Defaults to 'image'.
Returns:
dict: A dict containing the generated images and Control image.
"""
assert return_type in ['image', 'tensor', 'numpy']
# 0. Default height and width to unet
height = height or self.unet_sample_size * self.vae_scale_factor
width = width or self.unet_sample_size * self.vae_scale_factor
# 1. Check inputs. Raise error if not correct
self.check_inputs(prompt, height, width)
# 2. Define call parameters
batch_size = 1 if isinstance(prompt, str) else len(prompt)
device = self.device
# here `guidance_scale` is defined analog to the
# guidance weight `w` of equation (2)
# of the Imagen paper: https://arxiv.org/pdf/2205.11487.pdf .
# `guidance_scale = 1`
# corresponds to doing no classifier free guidance.
do_classifier_free_guidance = guidance_scale > 1.0
if is_model_wrapper(self.controlnet):
control_dtype = self.controlnet.module.dtype
else:
control_dtype = self.controlnet.dtype
controls = self.prepare_control(
control,
width,
height,
batch_size,
num_images_per_prompt,
device,
dtype=control_dtype)
if do_classifier_free_guidance:
controls = torch.cat([controls] * 2)
# 3. Encode input prompt
text_embeddings = self._encode_prompt(prompt, device,
num_images_per_prompt,
do_classifier_free_guidance,
negative_prompt)
# 4. Prepare timesteps
# self.scheduler.set_timesteps(num_inference_steps, device=device)
self.test_scheduler.set_timesteps(num_inference_steps)
timesteps = self.test_scheduler.timesteps
# 5. Prepare latent variables
num_channels_latents = self.unet.in_channels
latents = self.prepare_latents(
batch_size * num_images_per_prompt,
num_channels_latents,
height,
width,
text_embeddings.dtype,
device,
generator,
latents,
)
# 6. Prepare extra step kwargs.
extra_step_kwargs = self.prepare_extra_step_kwargs(generator, eta)
# 7. Denoising loop
if show_progress:
timesteps = tqdm(timesteps)
for i, t in enumerate(timesteps):
# expand the latents if we are doing classifier free guidance
latent_model_input = torch.cat(
[latents] * 2) if do_classifier_free_guidance else latents
latent_model_input = self.test_scheduler.scale_model_input(
latent_model_input, t)
down_block_res_samples, mid_block_res_sample = self.controlnet(
latent_model_input,
t,
encoder_hidden_states=text_embeddings,
controlnet_cond=controls,
return_dict=False,
)
down_block_res_samples = [
down_block_res_sample * controlnet_conditioning_scale
for down_block_res_sample in down_block_res_samples
]
mid_block_res_sample *= controlnet_conditioning_scale
# predict the noise residual
noise_pred = self.unet(
latent_model_input,
t,
encoder_hidden_states=text_embeddings,
down_block_additional_residuals=down_block_res_samples,
mid_block_additional_residual=mid_block_res_sample,
)['sample']
# perform guidance
if do_classifier_free_guidance:
noise_pred_uncond, noise_pred_text = noise_pred.chunk(2)
noise_pred = noise_pred_uncond + guidance_scale * (
noise_pred_text - noise_pred_uncond)
# compute the previous noisy sample x_t -> x_t-1
latents = self.test_scheduler.step(
noise_pred, t, latents, **extra_step_kwargs)['prev_sample']
# 8. Post-processing
image = self.decode_latents(latents)
if do_classifier_free_guidance:
controls = torch.split(controls, controls.shape[0] // 2, dim=0)[0]
if return_type == 'image':
image = self.output_to_pil(image)
controls = self.output_to_pil(controls * 2 - 1)
elif return_type == 'numpy':
image = image.cpu().numpy()
controls = controls.cpu().numpy()
else:
assert return_type == 'tensor', (
'Only support \'image\', \'numpy\' and \'tensor\' for '
f'return_type, but receive {return_type}')
return {'samples': image, 'controls': controls}
[文档] def forward(self, *args, **kwargs):
"""forward is not implemented now."""
raise NotImplementedError(
'Forward is not implemented now, please use infer.')
@MODELS.register_module()
[文档]class ControlStableDiffusionImg2Img(ControlStableDiffusion):
[文档] def _default_height_width(self, height, width, image):
if isinstance(image, list):
image = image[0]
if height is None:
if isinstance(image, Image.Image):
height = image.height
elif isinstance(image, torch.Tensor):
height = image.shape[3]
height = (height // 8) * 8 # round down to nearest multiple of 8
if width is None:
if isinstance(image, Image.Image):
width = image.width
elif isinstance(image, torch.Tensor):
width = image.shape[2]
width = (width // 8) * 8 # round down to nearest multiple of 8
return height, width
[文档] def get_timesteps(self, num_inference_steps, strength, device):
# get the original timestep using init_timestep
init_timestep = min(
int(num_inference_steps * strength), num_inference_steps)
t_start = max(num_inference_steps - init_timestep, 0)
timesteps = self.test_scheduler.timesteps[t_start:]
return timesteps, num_inference_steps - t_start
[文档] def prepare_latents(self,
image,
timestep,
batch_size,
num_images_per_prompt,
dtype,
device,
generator=None,
noise=None):
if not isinstance(image, (torch.Tensor, Image.Image, list)):
raise ValueError(
f'`image` has to be of type `torch.Tensor`, '
f' `PIL.Image.Image` or list but is {type(image)}')
image = image.to(device=device, dtype=dtype)
batch_size = batch_size * num_images_per_prompt
if isinstance(generator, list) and len(generator) != batch_size:
raise ValueError(
f'You have passed a list of generators of '
f' length {len(generator)}, but requested an effective batch'
f' size of {batch_size}. Make sure the batch size '
f' matches the length of the generators.')
if isinstance(generator, list):
init_latents = [
self.vae.encode(image[i:i +
1]).latent_dist.sample(generator[i])
for i in range(batch_size)
]
init_latents = torch.cat(init_latents, dim=0)
else:
init_latents = self.vae.encode(image).latent_dist.sample(generator)
init_latents = self.vae.config.scaling_factor * init_latents
vae_encode_latents = init_latents
if batch_size > init_latents.shape[0] and \
batch_size % init_latents.shape[0] == 0:
raise ValueError(
f'Cannot duplicate `image` of batch size'
f' {init_latents.shape[0]} to {batch_size} text prompts.')
else:
init_latents = torch.cat([init_latents], dim=0)
shape = init_latents.shape
if noise is None:
noise = torch.randn(
shape, generator=generator, device=device, dtype=dtype)
# get latents
init_latents = self.scheduler.add_noise(init_latents, noise, timestep)
return init_latents, vae_encode_latents
[文档] def prepare_latent_image(self, image, dtype):
if isinstance(image, torch.Tensor):
# Batch single image
if image.ndim == 3:
image = image.unsqueeze(0)
image = image.to(dtype=dtype)
else:
# preprocess image
if isinstance(image, (Image.Image, np.ndarray)):
image = [image]
if isinstance(image, list) and isinstance(image[0], Image.Image):
image = [np.array(i.convert('RGB'))[None, :] for i in image]
image = np.concatenate(image, axis=0)
elif isinstance(image, list) and isinstance(image[0], np.ndarray):
image = np.concatenate([i[None, :] for i in image], axis=0)
image = image.transpose(0, 3, 1, 2)
image = torch.from_numpy(image).to(dtype=dtype) / 127.5 - 1.0
return image
@torch.no_grad()
[文档] def infer(self,
prompt: Union[str, List[str]],
latent_image: Union[torch.FloatTensor, Image.Image,
List[torch.FloatTensor],
List[Image.Image]] = None,
latent_mask: torch.FloatTensor = None,
strength: float = 1.0,
height: Optional[int] = None,
width: Optional[int] = None,
control: Optional[Union[str, np.ndarray, torch.Tensor]] = None,
controlnet_conditioning_scale: float = 1.0,
num_inference_steps: int = 20,
guidance_scale: float = 7.5,
negative_prompt: Optional[Union[str, List[str]]] = None,
num_images_per_prompt: Optional[int] = 1,
eta: float = 0.0,
generator: Optional[torch.Generator] = None,
latents: Optional[torch.FloatTensor] = None,
return_type='image',
show_progress=True):
"""Function invoked when calling the pipeline for generation.
Args:
prompt (str or List[str]): The prompt or prompts to guide
the image generation.
height (int, Optional): The height in pixels of the generated
image. If not passed, the height will be
`self.unet_sample_size * self.vae_scale_factor` Defaults
to None.
width (int, Optional): The width in pixels of the generated image.
If not passed, the width will be
`self.unet_sample_size * self.vae_scale_factor` Defaults
to None.
num_inference_steps (int): The number of denoising steps.
More denoising steps usually lead to a higher quality image at
the expense of slower inference. Defaults to 50.
guidance_scale (float): Guidance scale as defined in Classifier-
Free Diffusion Guidance (https://arxiv.org/abs/2207.12598).
Defaults to 7.5
negative_prompt (str or List[str], optional): The prompt or
prompts not to guide the image generation. Ignored when not
using guidance (i.e., ignored if `guidance_scale` is less
than 1). Defaults to None.
num_images_per_prompt (int): The number of images to generate
per prompt. Defaults to 1.
eta (float): Corresponds to parameter eta (η) in the DDIM paper:
https://arxiv.org/abs/2010.02502. Only applies to
DDIMScheduler, will be ignored for others. Defaults to 0.0.
generator (torch.Generator, optional): A torch generator to make
generation deterministic. Defaults to None.
latents (torch.FloatTensor, optional): Pre-generated noisy latents,
sampled from a Gaussian distribution, to be used as inputs for
image generation. Can be used to tweak the same generation with
different prompts. If not provided, a latents tensor will be
generated by sampling using the supplied random `generator`.
Defaults to None.
return_type (str): The return type of the inference results.
Supported types are 'image', 'numpy', 'tensor'. If 'image'
is passed, a list of PIL images will be returned. If 'numpy'
is passed, a numpy array with shape [N, C, H, W] will be
returned, and the value range will be same as decoder's
output range. If 'tensor' is passed, the decoder's output
will be returned. Defaults to 'image'.
Returns:
dict: A dict containing the generated images and Control image.
"""
assert return_type in ['image', 'tensor', 'numpy']
# 0. Default height and width to unet
# height = height or self.unet_sample_size * self.vae_scale_factor
# width = width or self.unet_sample_size * self.vae_scale_factor
height, width = self._default_height_width(height, width, control)
# 1. Check inputs. Raise error if not correct
self.check_inputs(prompt, height, width)
# 2. Define call parameters
batch_size = 1 if isinstance(prompt, str) else len(prompt)
device = self.device
# here `guidance_scale` is defined analog to the
# guidance weight `w` of equation (2)
# of the Imagen paper: https://arxiv.org/pdf/2205.11487.pdf .
# `guidance_scale = 1`
# corresponds to doing no classifier free guidance.
do_classifier_free_guidance = guidance_scale > 1.0
if is_model_wrapper(self.controlnet):
control_dtype = self.controlnet.module.dtype
else:
control_dtype = self.controlnet.dtype
controls = self.prepare_control(
control,
width,
height,
batch_size,
num_images_per_prompt,
device,
dtype=control_dtype)
if do_classifier_free_guidance:
controls = torch.cat([controls] * 2)
latent_image = self.prepare_latent_image(latent_image,
self.controlnet.dtype)
# 3. Encode input prompt
text_embeddings = self._encode_prompt(prompt, device,
num_images_per_prompt,
do_classifier_free_guidance,
negative_prompt)
# 4. Prepare timesteps
# self.scheduler.set_timesteps(num_inference_steps, device=device)
self.test_scheduler.set_timesteps(num_inference_steps)
timesteps = self.test_scheduler.timesteps
timesteps, num_inference_steps = self.get_timesteps(
num_inference_steps, strength, device)
latent_timestep = timesteps[:1].repeat(batch_size *
num_images_per_prompt)
# 5. Prepare latent variables
latents, vae_encode_latents = self.prepare_latents(
latent_image,
latent_timestep,
batch_size,
num_images_per_prompt,
text_embeddings.dtype,
device,
generator,
noise=latents)
# 6. Prepare extra step kwargs.
extra_step_kwargs = self.prepare_test_scheduler_extra_step_kwargs(
generator, eta)
# 7. Denoising loop
if show_progress:
timesteps = tqdm(timesteps)
for i, t in enumerate(timesteps):
# expand the latents if we are doing classifier free guidance
latent_model_input = torch.cat(
[latents] * 2) if do_classifier_free_guidance else latents
latent_model_input = self.test_scheduler.scale_model_input(
latent_model_input, t)
down_block_res_samples, mid_block_res_sample = self.controlnet(
latent_model_input,
t,
encoder_hidden_states=text_embeddings,
controlnet_cond=controls,
return_dict=False,
)
down_block_res_samples = [
down_block_res_sample * controlnet_conditioning_scale
for down_block_res_sample in down_block_res_samples
]
mid_block_res_sample *= controlnet_conditioning_scale
# predict the noise residual
noise_pred = self.unet(
latent_model_input,
t,
encoder_hidden_states=text_embeddings,
down_block_additional_residuals=down_block_res_samples,
mid_block_additional_residual=mid_block_res_sample,
)['sample']
# perform guidance
if do_classifier_free_guidance:
noise_pred_uncond, noise_pred_text = noise_pred.chunk(2)
noise_pred = noise_pred_uncond + guidance_scale * (
noise_pred_text - noise_pred_uncond)
# compute the previous noisy sample x_t -> x_t-1
latents = self.test_scheduler.step(
noise_pred, t, latents, **extra_step_kwargs)['prev_sample']
if latent_mask is not None:
latents = latents * latent_mask + \
vae_encode_latents * (1.0 - latent_mask)
# 8. Post-processing
image = self.decode_latents(latents)
if do_classifier_free_guidance:
controls = torch.split(controls, controls.shape[0] // 2, dim=0)[0]
if return_type == 'image':
image = self.output_to_pil(image)
controls = self.output_to_pil(controls * 2 - 1)
elif return_type == 'numpy':
image = image.cpu().numpy()
controls = controls.cpu().numpy()
else:
assert return_type == 'tensor', (
'Only support \'image\', \'numpy\' and \'tensor\' for '
f'return_type, but receive {return_type}')
return {'samples': image, 'controls': controls}