Files
ai-toolkit/toolkit/train_tools.py

800 lines
30 KiB
Python

import argparse
import hashlib
import json
import os
import time
from typing import TYPE_CHECKING, Union
import sys
from torch.cuda.amp import GradScaler
from toolkit.paths import SD_SCRIPTS_ROOT
sys.path.append(SD_SCRIPTS_ROOT)
from diffusers import (
StableDiffusionPipeline,
DDPMScheduler,
EulerAncestralDiscreteScheduler,
DPMSolverMultistepScheduler,
DPMSolverSinglestepScheduler,
LMSDiscreteScheduler,
PNDMScheduler,
DDIMScheduler,
EulerDiscreteScheduler,
HeunDiscreteScheduler,
KDPM2DiscreteScheduler,
KDPM2AncestralDiscreteScheduler,
)
from library.lpw_stable_diffusion import StableDiffusionLongPromptWeightingPipeline
import torch
import re
SCHEDULER_LINEAR_START = 0.00085
SCHEDULER_LINEAR_END = 0.0120
SCHEDULER_TIMESTEPS = 1000
SCHEDLER_SCHEDULE = "scaled_linear"
UNET_ATTENTION_TIME_EMBED_DIM = 256 # XL
TEXT_ENCODER_2_PROJECTION_DIM = 1280
UNET_PROJECTION_CLASS_EMBEDDING_INPUT_DIM = 2816
def get_torch_dtype(dtype_str):
# if it is a torch dtype, return it
if isinstance(dtype_str, torch.dtype):
return dtype_str
if dtype_str == "float" or dtype_str == "fp32" or dtype_str == "single" or dtype_str == "float32":
return torch.float
if dtype_str == "fp16" or dtype_str == "half" or dtype_str == "float16":
return torch.float16
if dtype_str == "bf16" or dtype_str == "bfloat16":
return torch.bfloat16
return dtype_str
def replace_filewords_prompt(prompt, args: argparse.Namespace):
# if name_replace attr in args (may not be)
if hasattr(args, "name_replace") and args.name_replace is not None:
# replace [name] to args.name_replace
prompt = prompt.replace("[name]", args.name_replace)
if hasattr(args, "prepend") and args.prepend is not None:
# prepend to every item in prompt file
prompt = args.prepend + ' ' + prompt
if hasattr(args, "append") and args.append is not None:
# append to every item in prompt file
prompt = prompt + ' ' + args.append
return prompt
def replace_filewords_in_dataset_group(dataset_group, args: argparse.Namespace):
# if name_replace attr in args (may not be)
if hasattr(args, "name_replace") and args.name_replace is not None:
if not len(dataset_group.image_data) > 0:
# throw error
raise ValueError("dataset_group.image_data is empty")
for key in dataset_group.image_data:
dataset_group.image_data[key].caption = dataset_group.image_data[key].caption.replace(
"[name]", args.name_replace)
return dataset_group
def get_seeds_from_latents(latents):
# latents shape = (batch_size, 4, height, width)
# for speed we only use 8x8 slice of the first channel
seeds = []
# split batch up
for i in range(latents.shape[0]):
# use only first channel, multiply by 255 and convert to int
tensor = latents[i, 0, :, :] * 255.0 # shape = (height, width)
# slice 8x8
tensor = tensor[:8, :8]
# clip to 0-255
tensor = torch.clamp(tensor, 0, 255)
# convert to 8bit int
tensor = tensor.to(torch.uint8)
# convert to bytes
tensor_bytes = tensor.cpu().numpy().tobytes()
# hash
hash_object = hashlib.sha256(tensor_bytes)
# get hex
hex_dig = hash_object.hexdigest()
# convert to int
seed = int(hex_dig, 16) % (2 ** 32)
# append
seeds.append(seed)
return seeds
def get_noise_from_latents(latents):
seed_list = get_seeds_from_latents(latents)
noise = []
for seed in seed_list:
torch.manual_seed(seed)
torch.cuda.manual_seed(seed)
noise.append(torch.randn_like(latents[0]))
return torch.stack(noise)
# mix 0 is completely noise mean, mix 1 is completely target mean
def match_noise_to_target_mean_offset(noise, target, mix=0.5, dim=None):
dim = dim or (1, 2, 3)
# reduce mean of noise on dim 2, 3, keeping 0 and 1 intact
noise_mean = noise.mean(dim=dim, keepdim=True)
target_mean = target.mean(dim=dim, keepdim=True)
new_noise_mean = mix * target_mean + (1 - mix) * noise_mean
noise = noise - noise_mean + new_noise_mean
return noise
def sample_images(
accelerator,
args: argparse.Namespace,
epoch,
steps,
device,
vae,
tokenizer,
text_encoder,
unet,
prompt_replacement=None,
force_sample=False
):
"""
StableDiffusionLongPromptWeightingPipelineの改造版を使うようにしたので、clip skipおよびプロンプトの重みづけに対応した
"""
if not force_sample:
if args.sample_every_n_steps is None and args.sample_every_n_epochs is None:
return
if args.sample_every_n_epochs is not None:
# sample_every_n_steps は無視する
if epoch is None or epoch % args.sample_every_n_epochs != 0:
return
else:
if steps % args.sample_every_n_steps != 0 or epoch is not None: # steps is not divisible or end of epoch
return
is_sample_only = args.sample_only
is_generating_only = hasattr(args, "is_generating_only") and args.is_generating_only
print(f"\ngenerating sample images at step / サンプル画像生成 ステップ: {steps}")
if not os.path.isfile(args.sample_prompts):
print(f"No prompt file / プロンプトファイルがありません: {args.sample_prompts}")
return
org_vae_device = vae.device # CPUにいるはず
vae.to(device)
# read prompts
# with open(args.sample_prompts, "rt", encoding="utf-8") as f:
# prompts = f.readlines()
if args.sample_prompts.endswith(".txt"):
with open(args.sample_prompts, "r", encoding="utf-8") as f:
lines = f.readlines()
prompts = [line.strip() for line in lines if len(line.strip()) > 0 and line[0] != "#"]
elif args.sample_prompts.endswith(".json"):
with open(args.sample_prompts, "r", encoding="utf-8") as f:
prompts = json.load(f)
# schedulerを用意する
sched_init_args = {}
if args.sample_sampler == "ddim":
scheduler_cls = DDIMScheduler
elif args.sample_sampler == "ddpm": # ddpmはおかしくなるのでoptionから外してある
scheduler_cls = DDPMScheduler
elif args.sample_sampler == "pndm":
scheduler_cls = PNDMScheduler
elif args.sample_sampler == "lms" or args.sample_sampler == "k_lms":
scheduler_cls = LMSDiscreteScheduler
elif args.sample_sampler == "euler" or args.sample_sampler == "k_euler":
scheduler_cls = EulerDiscreteScheduler
elif args.sample_sampler == "euler_a" or args.sample_sampler == "k_euler_a":
scheduler_cls = EulerAncestralDiscreteScheduler
elif args.sample_sampler == "dpmsolver" or args.sample_sampler == "dpmsolver++":
scheduler_cls = DPMSolverMultistepScheduler
sched_init_args["algorithm_type"] = args.sample_sampler
elif args.sample_sampler == "dpmsingle":
scheduler_cls = DPMSolverSinglestepScheduler
elif args.sample_sampler == "heun":
scheduler_cls = HeunDiscreteScheduler
elif args.sample_sampler == "dpm_2" or args.sample_sampler == "k_dpm_2":
scheduler_cls = KDPM2DiscreteScheduler
elif args.sample_sampler == "dpm_2_a" or args.sample_sampler == "k_dpm_2_a":
scheduler_cls = KDPM2AncestralDiscreteScheduler
else:
scheduler_cls = DDIMScheduler
if args.v_parameterization:
sched_init_args["prediction_type"] = "v_prediction"
scheduler = scheduler_cls(
num_train_timesteps=SCHEDULER_TIMESTEPS,
beta_start=SCHEDULER_LINEAR_START,
beta_end=SCHEDULER_LINEAR_END,
beta_schedule=SCHEDLER_SCHEDULE,
**sched_init_args,
)
# clip_sample=Trueにする
if hasattr(scheduler.config, "clip_sample") and scheduler.config.clip_sample is False:
# print("set clip_sample to True")
scheduler.config.clip_sample = True
pipeline = StableDiffusionLongPromptWeightingPipeline(
text_encoder=text_encoder,
vae=vae,
unet=unet,
tokenizer=tokenizer,
scheduler=scheduler,
clip_skip=args.clip_skip,
safety_checker=None,
feature_extractor=None,
requires_safety_checker=False,
)
pipeline.to(device)
if is_generating_only:
save_dir = args.output_dir
else:
save_dir = args.output_dir + "/sample"
os.makedirs(save_dir, exist_ok=True)
rng_state = torch.get_rng_state()
cuda_rng_state = torch.cuda.get_rng_state() if torch.cuda.is_available() else None
with torch.no_grad():
with accelerator.autocast():
for i, prompt in enumerate(prompts):
if not accelerator.is_main_process:
continue
if isinstance(prompt, dict):
negative_prompt = prompt.get("negative_prompt")
sample_steps = prompt.get("sample_steps", 30)
width = prompt.get("width", 512)
height = prompt.get("height", 512)
scale = prompt.get("scale", 7.5)
seed = prompt.get("seed")
prompt = prompt.get("prompt")
prompt = replace_filewords_prompt(prompt, args)
negative_prompt = replace_filewords_prompt(negative_prompt, args)
else:
prompt = replace_filewords_prompt(prompt, args)
# prompt = prompt.strip()
# if len(prompt) == 0 or prompt[0] == "#":
# continue
# subset of gen_img_diffusers
prompt_args = prompt.split(" --")
prompt = prompt_args[0]
negative_prompt = None
sample_steps = 30
width = height = 512
scale = 7.5
seed = None
for parg in prompt_args:
try:
m = re.match(r"w (\d+)", parg, re.IGNORECASE)
if m:
width = int(m.group(1))
continue
m = re.match(r"h (\d+)", parg, re.IGNORECASE)
if m:
height = int(m.group(1))
continue
m = re.match(r"d (\d+)", parg, re.IGNORECASE)
if m:
seed = int(m.group(1))
continue
m = re.match(r"s (\d+)", parg, re.IGNORECASE)
if m: # steps
sample_steps = max(1, min(1000, int(m.group(1))))
continue
m = re.match(r"l ([\d\.]+)", parg, re.IGNORECASE)
if m: # scale
scale = float(m.group(1))
continue
m = re.match(r"n (.+)", parg, re.IGNORECASE)
if m: # negative prompt
negative_prompt = m.group(1)
continue
except ValueError as ex:
print(f"Exception in parsing / 解析エラー: {parg}")
print(ex)
if seed is not None:
torch.manual_seed(seed)
torch.cuda.manual_seed(seed)
if prompt_replacement is not None:
prompt = prompt.replace(prompt_replacement[0], prompt_replacement[1])
if negative_prompt is not None:
negative_prompt = negative_prompt.replace(prompt_replacement[0], prompt_replacement[1])
height = max(64, height - height % 8) # round to divisible by 8
width = max(64, width - width % 8) # round to divisible by 8
print(f"prompt: {prompt}")
print(f"negative_prompt: {negative_prompt}")
print(f"height: {height}")
print(f"width: {width}")
print(f"sample_steps: {sample_steps}")
print(f"scale: {scale}")
image = pipeline(
prompt=prompt,
height=height,
width=width,
num_inference_steps=sample_steps,
guidance_scale=scale,
negative_prompt=negative_prompt,
).images[0]
ts_str = time.strftime("%Y%m%d%H%M%S", time.localtime())
num_suffix = f"e{epoch:06d}" if epoch is not None else f"{steps:06d}"
seed_suffix = "" if seed is None else f"_{seed}"
if is_generating_only:
img_filename = (
f"{'' if args.output_name is None else args.output_name + '_'}{ts_str}_{num_suffix}_{i:02d}{seed_suffix}.png"
)
else:
img_filename = (
f"{'' if args.output_name is None else args.output_name + '_'}{ts_str}_{i:04d}{seed_suffix}.png"
)
if is_sample_only:
# make prompt txt file
img_path_no_ext = os.path.join(save_dir, img_filename[:-4])
with open(img_path_no_ext + ".txt", "w") as f:
# put prompt in txt file
f.write(prompt)
# close file
f.close()
image.save(os.path.join(save_dir, img_filename))
# wandb有効時のみログを送信
try:
wandb_tracker = accelerator.get_tracker("wandb")
try:
import wandb
except ImportError: # 事前に一度確認するのでここはエラー出ないはず
raise ImportError("No wandb / wandb がインストールされていないようです")
wandb_tracker.log({f"sample_{i}": wandb.Image(image)})
except: # wandb 無効時
pass
# clear pipeline and cache to reduce vram usage
del pipeline
torch.cuda.empty_cache()
torch.set_rng_state(rng_state)
if cuda_rng_state is not None:
torch.cuda.set_rng_state(cuda_rng_state)
vae.to(org_vae_device)
# https://www.crosslabs.org//blog/diffusion-with-offset-noise
def apply_noise_offset(noise, noise_offset):
if noise_offset is None or noise_offset < 0.0000001:
return noise
noise = noise + noise_offset * torch.randn((noise.shape[0], noise.shape[1], 1, 1), device=noise.device)
return noise
if TYPE_CHECKING:
from toolkit.stable_diffusion_model import PromptEmbeds
def concat_prompt_embeddings(
unconditional: 'PromptEmbeds',
conditional: 'PromptEmbeds',
n_imgs: int,
):
from toolkit.stable_diffusion_model import PromptEmbeds
text_embeds = torch.cat(
[unconditional.text_embeds, conditional.text_embeds]
).repeat_interleave(n_imgs, dim=0)
pooled_embeds = None
if unconditional.pooled_embeds is not None and conditional.pooled_embeds is not None:
pooled_embeds = torch.cat(
[unconditional.pooled_embeds, conditional.pooled_embeds]
).repeat_interleave(n_imgs, dim=0)
return PromptEmbeds([text_embeds, pooled_embeds])
def addnet_hash_safetensors(b):
"""New model hash used by sd-webui-additional-networks for .safetensors format files"""
hash_sha256 = hashlib.sha256()
blksize = 1024 * 1024
b.seek(0)
header = b.read(8)
n = int.from_bytes(header, "little")
offset = n + 8
b.seek(offset)
for chunk in iter(lambda: b.read(blksize), b""):
hash_sha256.update(chunk)
return hash_sha256.hexdigest()
def addnet_hash_legacy(b):
"""Old model hash used by sd-webui-additional-networks for .safetensors format files"""
m = hashlib.sha256()
b.seek(0x100000)
m.update(b.read(0x10000))
return m.hexdigest()[0:8]
if TYPE_CHECKING:
from transformers import CLIPTextModel, CLIPTokenizer, CLIPTextModelWithProjection
def text_tokenize(
tokenizer: 'CLIPTokenizer',
prompts: list[str],
truncate: bool = True,
max_length: int = None,
max_length_multiplier: int = 4,
):
# allow fo up to 4x the max length for long prompts
if max_length is None:
if truncate:
max_length = tokenizer.model_max_length
else:
# allow up to 4x the max length for long prompts
max_length = tokenizer.model_max_length * max_length_multiplier
input_ids = tokenizer(
prompts,
padding='max_length',
max_length=max_length,
truncation=True,
return_tensors="pt",
).input_ids
if truncate or max_length == tokenizer.model_max_length:
return input_ids
else:
# remove additional padding
num_chunks = input_ids.shape[1] // tokenizer.model_max_length
chunks = torch.chunk(input_ids, chunks=num_chunks, dim=1)
# New list to store non-redundant chunks
non_redundant_chunks = []
for chunk in chunks:
if not chunk.eq(chunk[0, 0]).all(): # Check if all elements in the chunk are the same as the first element
non_redundant_chunks.append(chunk)
input_ids = torch.cat(non_redundant_chunks, dim=1)
return input_ids
# https://github.com/huggingface/diffusers/blob/78922ed7c7e66c20aa95159c7b7a6057ba7d590d/src/diffusers/pipelines/stable_diffusion_xl/pipeline_stable_diffusion_xl.py#L334-L348
def text_encode_xl(
text_encoder: Union['CLIPTextModel', 'CLIPTextModelWithProjection'],
tokens: torch.FloatTensor,
num_images_per_prompt: int = 1,
max_length: int = 77, # not sure what default to put here, always pass one?
truncate: bool = True,
):
if truncate:
# normal short prompt 77 tokens max
prompt_embeds = text_encoder(
tokens.to(text_encoder.device), output_hidden_states=True
)
pooled_prompt_embeds = prompt_embeds[0]
prompt_embeds = prompt_embeds.hidden_states[-2] # always penultimate layer
else:
# handle long prompts
prompt_embeds_list = []
tokens = tokens.to(text_encoder.device)
pooled_prompt_embeds = None
for i in range(0, tokens.shape[-1], max_length):
# todo run it through the in a single batch
section_tokens = tokens[:, i: i + max_length]
embeds = text_encoder(section_tokens, output_hidden_states=True)
pooled_prompt_embed = embeds[0]
if pooled_prompt_embeds is None:
# we only want the first ( I think??)
pooled_prompt_embeds = pooled_prompt_embed
prompt_embed = embeds.hidden_states[-2] # always penultimate layer
prompt_embeds_list.append(prompt_embed)
prompt_embeds = torch.cat(prompt_embeds_list, dim=1)
bs_embed, seq_len, _ = prompt_embeds.shape
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)
return prompt_embeds, pooled_prompt_embeds
def encode_prompts_xl(
tokenizers: list['CLIPTokenizer'],
text_encoders: list[Union['CLIPTextModel', 'CLIPTextModelWithProjection']],
prompts: list[str],
prompts2: Union[list[str], None],
num_images_per_prompt: int = 1,
use_text_encoder_1: bool = True, # sdxl
use_text_encoder_2: bool = True, # sdxl
truncate: bool = True,
max_length=None,
dropout_prob=0.0,
) -> tuple[torch.FloatTensor, torch.FloatTensor]:
# text_encoder and text_encoder_2's penuultimate layer's output
text_embeds_list = []
pooled_text_embeds = None # always text_encoder_2's pool
if prompts2 is None:
prompts2 = prompts
for idx, (tokenizer, text_encoder) in enumerate(zip(tokenizers, text_encoders)):
# todo, we are using a blank string to ignore that encoder for now.
# find a better way to do this (zeroing?, removing it from the unet?)
prompt_list_to_use = prompts if idx == 0 else prompts2
if idx == 0 and not use_text_encoder_1:
prompt_list_to_use = ["" for _ in prompts]
if idx == 1 and not use_text_encoder_2:
prompt_list_to_use = ["" for _ in prompts]
if dropout_prob > 0.0:
# randomly drop out prompts
prompt_list_to_use = [
prompt if torch.rand(1).item() > dropout_prob else "" for prompt in prompt_list_to_use
]
text_tokens_input_ids = text_tokenize(tokenizer, prompt_list_to_use, truncate=truncate, max_length=max_length)
# set the max length for the next one
if idx == 0:
max_length = text_tokens_input_ids.shape[-1]
text_embeds, pooled_text_embeds = text_encode_xl(
text_encoder, text_tokens_input_ids, num_images_per_prompt, max_length=tokenizer.model_max_length,
truncate=truncate
)
text_embeds_list.append(text_embeds)
bs_embed = pooled_text_embeds.shape[0]
pooled_text_embeds = pooled_text_embeds.repeat(1, num_images_per_prompt).view(
bs_embed * num_images_per_prompt, -1
)
return torch.concat(text_embeds_list, dim=-1), pooled_text_embeds
# ref for long prompts https://github.com/huggingface/diffusers/issues/2136
def text_encode(text_encoder: 'CLIPTextModel', tokens, truncate: bool = True, max_length=None):
if max_length is None and not truncate:
raise ValueError("max_length must be set if truncate is True")
try:
tokens = tokens.to(text_encoder.device)
except Exception as e:
print(e)
print("tokens.device", tokens.device)
print("text_encoder.device", text_encoder.device)
raise e
if truncate:
return text_encoder(tokens)[0]
else:
# handle long prompts
prompt_embeds_list = []
for i in range(0, tokens.shape[-1], max_length):
prompt_embeds = text_encoder(tokens[:, i: i + max_length])[0]
prompt_embeds_list.append(prompt_embeds)
return torch.cat(prompt_embeds_list, dim=1)
def encode_prompts(
tokenizer: 'CLIPTokenizer',
text_encoder: 'CLIPTextModel',
prompts: list[str],
truncate: bool = True,
max_length=None,
dropout_prob=0.0,
):
if max_length is None:
max_length = tokenizer.model_max_length
if dropout_prob > 0.0:
# randomly drop out prompts
prompts = [
prompt if torch.rand(1).item() > dropout_prob else "" for prompt in prompts
]
text_tokens = text_tokenize(tokenizer, prompts, truncate=truncate, max_length=max_length)
text_embeddings = text_encode(text_encoder, text_tokens, truncate=truncate, max_length=max_length)
return text_embeddings
# for XL
def get_add_time_ids(
height: int,
width: int,
dynamic_crops: bool = False,
dtype: torch.dtype = torch.float32,
):
if dynamic_crops:
# random float scale between 1 and 3
random_scale = torch.rand(1).item() * 2 + 1
original_size = (int(height * random_scale), int(width * random_scale))
# random position
crops_coords_top_left = (
torch.randint(0, original_size[0] - height, (1,)).item(),
torch.randint(0, original_size[1] - width, (1,)).item(),
)
target_size = (height, width)
else:
original_size = (height, width)
crops_coords_top_left = (0, 0)
target_size = (height, width)
# this is expected as 6
add_time_ids = list(original_size + crops_coords_top_left + target_size)
# this is expected as 2816
passed_add_embed_dim = (
UNET_ATTENTION_TIME_EMBED_DIM * len(add_time_ids) # 256 * 6
+ TEXT_ENCODER_2_PROJECTION_DIM # + 1280
)
if passed_add_embed_dim != UNET_PROJECTION_CLASS_EMBEDDING_INPUT_DIM:
raise ValueError(
f"Model expects an added time embedding vector of length {UNET_PROJECTION_CLASS_EMBEDDING_INPUT_DIM}, but a vector of {passed_add_embed_dim} was created. The model has an incorrect config. Please check `unet.config.time_embedding_type` and `text_encoder_2.config.projection_dim`."
)
add_time_ids = torch.tensor([add_time_ids], dtype=dtype)
return add_time_ids
def concat_embeddings(
unconditional: torch.FloatTensor,
conditional: torch.FloatTensor,
n_imgs: int,
):
return torch.cat([unconditional, conditional]).repeat_interleave(n_imgs, dim=0)
def add_all_snr_to_noise_scheduler(noise_scheduler, device):
if hasattr(noise_scheduler, "all_snr"):
return
# compute it
with torch.no_grad():
alphas_cumprod = noise_scheduler.alphas_cumprod
sqrt_alphas_cumprod = torch.sqrt(alphas_cumprod)
sqrt_one_minus_alphas_cumprod = torch.sqrt(1.0 - alphas_cumprod)
alpha = sqrt_alphas_cumprod
sigma = sqrt_one_minus_alphas_cumprod
all_snr = (alpha / sigma) ** 2
all_snr.requires_grad = False
noise_scheduler.all_snr = all_snr.to(device)
def get_all_snr(noise_scheduler, device):
if hasattr(noise_scheduler, "all_snr"):
return noise_scheduler.all_snr.to(device)
# compute it
with torch.no_grad():
alphas_cumprod = noise_scheduler.alphas_cumprod
sqrt_alphas_cumprod = torch.sqrt(alphas_cumprod)
sqrt_one_minus_alphas_cumprod = torch.sqrt(1.0 - alphas_cumprod)
alpha = sqrt_alphas_cumprod
sigma = sqrt_one_minus_alphas_cumprod
all_snr = (alpha / sigma) ** 2
all_snr.requires_grad = False
return all_snr.to(device)
class LearnableSNRGamma:
"""
This is a trainer for learnable snr gamma
It will adapt to the dataset and attempt to adjust the snr multiplier to balance the loss over the timesteps
"""
def __init__(self, noise_scheduler: Union['DDPMScheduler'], device='cuda'):
self.device = device
self.noise_scheduler: Union['DDPMScheduler'] = noise_scheduler
self.offset_1 = torch.nn.Parameter(torch.tensor(0.0, dtype=torch.float32, device=device))
self.offset_2 = torch.nn.Parameter(torch.tensor(0.777, dtype=torch.float32, device=device))
self.scale = torch.nn.Parameter(torch.tensor(4.14, dtype=torch.float32, device=device))
self.gamma = torch.nn.Parameter(torch.tensor(2.03, dtype=torch.float32, device=device))
self.optimizer = torch.optim.AdamW([self.offset_1, self.offset_2, self.gamma, self.scale], lr=0.01)
self.buffer = []
self.max_buffer_size = 20
def forward(self, loss, timesteps):
# do a our train loop for lsnr here and return our values detached
loss = loss.detach()
with torch.no_grad():
loss_chunks = torch.chunk(loss, loss.shape[0], dim=0)
for loss_chunk in loss_chunks:
self.buffer.append(loss_chunk.mean().detach())
if len(self.buffer) > self.max_buffer_size:
self.buffer.pop(0)
all_snr = get_all_snr(self.noise_scheduler, loss.device)
snr: torch.Tensor = torch.stack([all_snr[t] for t in timesteps]).detach().float().to(loss.device)
base_snrs = snr.clone().detach()
snr.requires_grad = True
snr = (snr + self.offset_1) * self.scale + self.offset_2
gamma_over_snr = torch.div(torch.ones_like(snr) * self.gamma, snr)
snr_weight = torch.abs(gamma_over_snr).float().to(loss.device) # directly using gamma over snr
snr_adjusted_loss = loss * snr_weight
with torch.no_grad():
target = torch.mean(torch.stack(self.buffer)).detach()
# local_loss = torch.mean(torch.abs(snr_adjusted_loss - target))
squared_differences = (snr_adjusted_loss - target) ** 2
local_loss = torch.mean(squared_differences)
local_loss.backward()
self.optimizer.step()
self.optimizer.zero_grad()
return base_snrs, self.gamma.detach(), self.offset_1.detach(), self.offset_2.detach(), self.scale.detach()
def apply_learnable_snr_gos(
loss,
timesteps,
learnable_snr_trainer: LearnableSNRGamma
):
snr, gamma, offset_1, offset_2, scale = learnable_snr_trainer.forward(loss, timesteps)
snr = (snr + offset_1) * scale + offset_2
gamma_over_snr = torch.div(torch.ones_like(snr) * gamma, snr)
snr_weight = torch.abs(gamma_over_snr).float().to(loss.device) # directly using gamma over snr
snr_adjusted_loss = loss * snr_weight
return snr_adjusted_loss
def apply_snr_weight(
loss,
timesteps,
noise_scheduler: Union['DDPMScheduler'],
gamma,
fixed=False,
):
# will get it from noise scheduler if exist or will calculate it if not
all_snr = get_all_snr(noise_scheduler, loss.device)
# step_indices = []
# for t in timesteps:
# for i, st in enumerate(noise_scheduler.timesteps):
# if st == t:
# step_indices.append(i)
# break
# this breaks on some schedulers
# step_indices = [(noise_scheduler.timesteps == t).nonzero().item() for t in timesteps]
offset = 0
if noise_scheduler.timesteps[0] == 1000:
offset = 1
snr = torch.stack([all_snr[t - offset] for t in timesteps])
gamma_over_snr = torch.div(torch.ones_like(snr) * gamma, snr)
if fixed:
snr_weight = gamma_over_snr.float().to(loss.device) # directly using gamma over snr
else:
snr_weight = torch.minimum(gamma_over_snr, torch.ones_like(gamma_over_snr)).float().to(loss.device)
snr_adjusted_loss = loss * snr_weight
return snr_adjusted_loss