Use euler_a for samples in learning scripts; backported improvement from Dreambooth to Textual Inversion

4 files changed, 230 insertions, 203 deletions

diff --git a/data/dreambooth/csv.py b/data/dreambooth/csv.py
index 99bcf12..1676d35 100644
--- a/data/dreambooth/csv.py
+++ b/data/dreambooth/csv.py
@@ -2,7 +2,6 @@ import math
 import os
 import pandas as pd
 from pathlib import Path
-import PIL
 import pytorch_lightning as pl
 from PIL import Image
 from torch.utils.data import Dataset, DataLoader, random_split
diff --git a/data/textual_inversion/csv.py b/data/textual_inversion/csv.py
index 0d1e96e..f306c7a 100644
--- a/data/textual_inversion/csv.py
+++ b/data/textual_inversion/csv.py
@@ -1,11 +1,10 @@
 import os
 import numpy as np
 import pandas as pd
-import random
-import PIL
+from pathlib import Path
+import math
 import pytorch_lightning as pl
 from PIL import Image
-import torch
 from torch.utils.data import Dataset, DataLoader, random_split
 from torchvision import transforms
 
@@ -13,29 +12,32 @@ from torchvision import transforms
 class CSVDataModule(pl.LightningDataModule):
     def __init__(self,
                  batch_size,
-                 data_root,
+                 data_file,
                  tokenizer,
                  size=512,
                  repeats=100,
                  interpolation="bicubic",
                  placeholder_token="*",
-                 flip_p=0.5,
                  center_crop=False):
         super().__init__()
 
-        self.data_root = data_root
+        self.data_file = Path(data_file)
+
+        if not self.data_file.is_file():
+            raise ValueError("data_file must be a file")
+
+        self.data_root = self.data_file.parent
         self.tokenizer = tokenizer
         self.size = size
         self.repeats = repeats
         self.placeholder_token = placeholder_token
         self.center_crop = center_crop
-        self.flip_p = flip_p
         self.interpolation = interpolation
 
         self.batch_size = batch_size
 
     def prepare_data(self):
-        metadata = pd.read_csv(f'{self.data_root}/list.csv')
+        metadata = pd.read_csv(self.data_file)
         image_paths = [os.path.join(self.data_root, f_path) for f_path in metadata['image'].values]
         captions = [caption for caption in metadata['caption'].values]
         skips = [skip for skip in metadata['skip'].values]
@@ -47,9 +49,9 @@ class CSVDataModule(pl.LightningDataModule):
         self.data_train, self.data_val = random_split(self.data_full, [train_set_size, valid_set_size])
 
         train_dataset = CSVDataset(self.data_train, self.tokenizer, size=self.size, repeats=self.repeats, interpolation=self.interpolation,
-                                   flip_p=self.flip_p, placeholder_token=self.placeholder_token, center_crop=self.center_crop)
+                                   placeholder_token=self.placeholder_token, center_crop=self.center_crop)
         val_dataset = CSVDataset(self.data_val, self.tokenizer, size=self.size, interpolation=self.interpolation,
-                                 flip_p=self.flip_p, placeholder_token=self.placeholder_token, center_crop=self.center_crop)
+                                 placeholder_token=self.placeholder_token, center_crop=self.center_crop)
         self.train_dataloader_ = DataLoader(train_dataset, batch_size=self.batch_size, shuffle=True)
         self.val_dataloader_ = DataLoader(val_dataset, batch_size=self.batch_size)
 
@@ -67,48 +69,54 @@ class CSVDataset(Dataset):
                  size=512,
                  repeats=1,
                  interpolation="bicubic",
-                 flip_p=0.5,
                  placeholder_token="*",
                  center_crop=False,
+                 batch_size=1,
                  ):
 
         self.data = data
         self.tokenizer = tokenizer
-
-        self.num_images = len(self.data)
-        self._length = self.num_images * repeats
-
         self.placeholder_token = placeholder_token
+        self.batch_size = batch_size
+        self.cache = {}
 
-        self.size = size
-        self.center_crop = center_crop
-        self.interpolation = {"linear": PIL.Image.LINEAR,
-                              "bilinear": PIL.Image.BILINEAR,
-                              "bicubic": PIL.Image.BICUBIC,
-                              "lanczos": PIL.Image.LANCZOS,
-                              }[interpolation]
-        self.flip = transforms.RandomHorizontalFlip(p=flip_p)
+        self.num_instance_images = len(self.data)
+        self._length = self.num_instance_images * repeats
 
-        self.cache = {}
+        self.interpolation = {"linear": transforms.InterpolationMode.NEAREST,
+                              "bilinear": transforms.InterpolationMode.BILINEAR,
+                              "bicubic": transforms.InterpolationMode.BICUBIC,
+                              "lanczos": transforms.InterpolationMode.LANCZOS,
+                              }[interpolation]
+        self.image_transforms = transforms.Compose(
+            [
+                transforms.Resize(size, interpolation=self.interpolation),
+                transforms.CenterCrop(size) if center_crop else transforms.RandomCrop(size),
+                transforms.RandomHorizontalFlip(),
+                transforms.ToTensor(),
+                transforms.Normalize([0.5], [0.5]),
+            ]
+        )
 
     def __len__(self):
-        return self._length
+        return math.ceil(self._length / self.batch_size) * self.batch_size
 
-    def get_example(self, i, flipped):
-        image_path, text = self.data[i % self.num_images]
+    def get_example(self, i):
+        image_path, text = self.data[i % self.num_instance_images]
 
         if image_path in self.cache:
             return self.cache[image_path]
 
         example = {}
-        image = Image.open(image_path)
 
-        if not image.mode == "RGB":
-            image = image.convert("RGB")
+        instance_image = Image.open(image_path)
+        if not instance_image.mode == "RGB":
+            instance_image = instance_image.convert("RGB")
 
         text = text.format(self.placeholder_token)
 
-        example["prompt"] = text
+        example["prompts"] = text
+        example["pixel_values"] = instance_image
         example["input_ids"] = self.tokenizer(
             text,
             padding="max_length",
@@ -117,29 +125,15 @@ class CSVDataset(Dataset):
             return_tensors="pt",
         ).input_ids[0]
 
-        # default to score-sde preprocessing
-        img = np.array(image).astype(np.uint8)
-
-        if self.center_crop:
-            crop = min(img.shape[0], img.shape[1])
-            h, w, = img.shape[0], img.shape[1]
-            img = img[(h - crop) // 2:(h + crop) // 2,
-                      (w - crop) // 2:(w + crop) // 2]
-
-        image = Image.fromarray(img)
-        image = image.resize((self.size, self.size),
-                             resample=self.interpolation)
-        image = self.flip(image)
-        image = np.array(image).astype(np.uint8)
-        image = (image / 127.5 - 1.0).astype(np.float32)
-
-        example["key"] = "-".join([image_path, "-", str(flipped)])
-        example["pixel_values"] = torch.from_numpy(image).permute(2, 0, 1)
-
         self.cache[image_path] = example
         return example
 
     def __getitem__(self, i):
-        flipped = random.choice([False, True])
-        example = self.get_example(i, flipped)
+        example = {}
+        unprocessed_example = self.get_example(i)
+
+        example["prompts"] = unprocessed_example["prompts"]
+        example["input_ids"] = unprocessed_example["input_ids"]
+        example["pixel_values"] = self.image_transforms(unprocessed_example["pixel_values"])
+
         return example
diff --git a/dreambooth.py b/dreambooth.py
index 4d7366c..744d1bc 100644
--- a/dreambooth.py
+++ b/dreambooth.py
@@ -14,12 +14,14 @@ from accelerate import Accelerator
 from accelerate.logging import get_logger
 from accelerate.utils import LoggerType, set_seed
 from diffusers import AutoencoderKL, DDPMScheduler, PNDMScheduler, LMSDiscreteScheduler, StableDiffusionPipeline, UNet2DConditionModel
+from schedulers.scheduling_euler_a import EulerAScheduler
 from diffusers.optimization import get_scheduler
 from pipelines.stable_diffusion.no_check import NoCheck
 from PIL import Image
 from tqdm.auto import tqdm
 from transformers import CLIPFeatureExtractor, CLIPTextModel, CLIPTokenizer
 from slugify import slugify
+from pipelines.stable_diffusion.vlpn_stable_diffusion import VlpnStableDiffusion
 import json
 
 from data.dreambooth.csv import CSVDataModule
@@ -215,7 +217,7 @@ def parse_args():
     parser.add_argument(
         "--sample_steps",
         type=int,
-        default=80,
+        default=30,
         help="Number of steps for sample generation. Higher values will result in more detailed samples, but longer runtimes.",
     )
     parser.add_argument(
@@ -377,15 +379,16 @@ class Checkpointer:
         samples_path = Path(self.output_dir).joinpath("samples")
 
         unwrapped = self.accelerator.unwrap_model(self.unet)
-        pipeline = StableDiffusionPipeline(
+        scheduler = EulerAScheduler(
+            beta_start=0.00085, beta_end=0.012, beta_schedule="scaled_linear"
+        )
+
+        pipeline = VlpnStableDiffusion(
             text_encoder=self.text_encoder,
             vae=self.vae,
             unet=unwrapped,
             tokenizer=self.tokenizer,
-            scheduler=LMSDiscreteScheduler(
-                beta_start=0.00085, beta_end=0.012, beta_schedule="scaled_linear"
-            ),
-            safety_checker=NoCheck(),
+            scheduler=scheduler,
             feature_extractor=CLIPFeatureExtractor.from_pretrained("openai/clip-vit-base-patch32"),
         ).to(self.accelerator.device)
         pipeline.enable_attention_slicing()
@@ -411,6 +414,8 @@ class Checkpointer:
                 prompt = [prompt for i, batch in data_enum for j, prompt in enumerate(
                     batch["prompts"]) if i * val_data.batch_size + j < self.sample_batch_size]
 
+                generator = torch.Generator(device="cuda").manual_seed(self.seed + i)
+
                 with self.accelerator.autocast():
                     samples = pipeline(
                         prompt=prompt,
@@ -420,10 +425,13 @@ class Checkpointer:
                         guidance_scale=guidance_scale,
                         eta=eta,
                         num_inference_steps=num_inference_steps,
+                        generator=generator,
                         output_type='pil'
                     )["sample"]
 
                 all_samples += samples
+
+                del generator
                 del samples
 
             image_grid = make_grid(all_samples, self.stable_sample_batches, self.sample_batch_size)
@@ -444,6 +452,8 @@ class Checkpointer:
                 prompt = [prompt for i, batch in data_enum for j, prompt in enumerate(
                     batch["prompts"]) if i * data.batch_size + j < self.sample_batch_size]
 
+                generator = torch.Generator(device="cuda").manual_seed(self.seed + i)
+
                 with self.accelerator.autocast():
                     samples = pipeline(
                         prompt=prompt,
@@ -452,10 +462,13 @@ class Checkpointer:
                         guidance_scale=guidance_scale,
                         eta=eta,
                         num_inference_steps=num_inference_steps,
+                        generator=generator,
                         output_type='pil'
                     )["sample"]
 
                 all_samples += samples
+
+                del generator
                 del samples
 
             image_grid = make_grid(all_samples, self.random_sample_batches, self.sample_batch_size)
@@ -465,6 +478,7 @@ class Checkpointer:
             del image_grid
 
         del unwrapped
+        del scheduler
         del pipeline
 
         if torch.cuda.is_available():
diff --git a/textual_inversion.py b/textual_inversion.py
index 399d876..7a7d7fc 100644
--- a/textual_inversion.py
+++ b/textual_inversion.py
@@ -3,6 +3,8 @@ import itertools
 import math
 import os
 import datetime
+import logging
+from pathlib import Path
 
 import numpy as np
 import torch
@@ -13,12 +15,13 @@ from accelerate import Accelerator
 from accelerate.logging import get_logger
 from accelerate.utils import LoggerType, set_seed
 from diffusers import AutoencoderKL, DDPMScheduler, LMSDiscreteScheduler, StableDiffusionPipeline, UNet2DConditionModel
+from schedulers.scheduling_euler_a import EulerAScheduler
 from diffusers.optimization import get_scheduler
-from pipelines.stable_diffusion.no_check import NoCheck
 from PIL import Image
 from tqdm.auto import tqdm
 from transformers import CLIPFeatureExtractor, CLIPTextModel, CLIPTokenizer
 from slugify import slugify
+from pipelines.stable_diffusion.vlpn_stable_diffusion import VlpnStableDiffusion
 import json
 import os
 
@@ -44,10 +47,10 @@ def parse_args():
         help="Pretrained tokenizer name or path if not the same as model_name",
     )
     parser.add_argument(
-        "--train_data_dir",
+        "--train_data_file",
         type=str,
         default=None,
-        help="A folder containing the training data."
+        help="A CSV file containing the training data."
     )
     parser.add_argument(
         "--placeholder_token",
@@ -146,6 +149,11 @@ def parse_args():
         help="Number of steps for the warmup in the lr scheduler."
     )
     parser.add_argument(
+        "--use_8bit_adam",
+        action="store_true",
+        help="Whether or not to use 8-bit Adam from bitsandbytes."
+    )
+    parser.add_argument(
         "--adam_beta1",
         type=float,
         default=0.9,
@@ -225,7 +233,7 @@ def parse_args():
     parser.add_argument(
         "--sample_steps",
         type=int,
-        default=50,
+        default=30,
         help="Number of steps for sample generation. Higher values will result in more detailed samples, but longer runtimes.",
     )
     parser.add_argument(
@@ -261,8 +269,8 @@ def parse_args():
     if env_local_rank != -1 and env_local_rank != args.local_rank:
         args.local_rank = env_local_rank
 
-    if args.train_data_dir is None:
-        raise ValueError("You must specify --train_data_dir")
+    if args.train_data_file is None:
+        raise ValueError("You must specify --train_data_file")
 
     if args.pretrained_model_name_or_path is None:
         raise ValueError("You must specify --pretrained_model_name_or_path")
@@ -333,53 +341,51 @@ class Checkpointer:
     @torch.no_grad()
     def checkpoint(self, step, postfix, text_encoder, save_samples=True, path=None):
         print("Saving checkpoint for step %d..." % step)
-        with self.accelerator.autocast():
-            if path is None:
-                checkpoints_path = f"{self.output_dir}/checkpoints"
-                os.makedirs(checkpoints_path, exist_ok=True)
-
-            unwrapped = self.accelerator.unwrap_model(text_encoder)
-
-            # Save a checkpoint
-            learned_embeds = unwrapped.get_input_embeddings().weight[self.placeholder_token_id]
-            learned_embeds_dict = {self.placeholder_token: learned_embeds.detach().cpu()}
-
-            filename = f"%s_%d_%s.bin" % (slugify(self.placeholder_token), step, postfix)
-            if path is not None:
-                torch.save(learned_embeds_dict, path)
-            else:
-                torch.save(learned_embeds_dict, f"{checkpoints_path}/{filename}")
-                torch.save(learned_embeds_dict, f"{checkpoints_path}/last.bin")
-            del unwrapped
-            del learned_embeds
+
+        if path is None:
+            checkpoints_path = f"{self.output_dir}/checkpoints"
+            os.makedirs(checkpoints_path, exist_ok=True)
+
+        unwrapped = self.accelerator.unwrap_model(text_encoder)
+
+        # Save a checkpoint
+        learned_embeds = unwrapped.get_input_embeddings().weight[self.placeholder_token_id]
+        learned_embeds_dict = {self.placeholder_token: learned_embeds.detach().cpu()}
+
+        filename = f"%s_%d_%s.bin" % (slugify(self.placeholder_token), step, postfix)
+        if path is not None:
+            torch.save(learned_embeds_dict, path)
+        else:
+            torch.save(learned_embeds_dict, f"{checkpoints_path}/{filename}")
+            torch.save(learned_embeds_dict, f"{checkpoints_path}/last.bin")
+
+        del unwrapped
+        del learned_embeds
 
     @torch.no_grad()
-    def save_samples(self, mode, step, text_encoder, height, width, guidance_scale, eta, num_inference_steps):
-        samples_path = f"{self.output_dir}/samples/{mode}"
-        os.makedirs(samples_path, exist_ok=True)
-        checker = NoCheck()
+    def save_samples(self, step, text_encoder, height, width, guidance_scale, eta, num_inference_steps):
+        samples_path = Path(self.output_dir).joinpath("samples")
 
         unwrapped = self.accelerator.unwrap_model(text_encoder)
+        scheduler = EulerAScheduler(
+            beta_start=0.00085, beta_end=0.012, beta_schedule="scaled_linear"
+        )
+
         # Save a sample image
-        pipeline = StableDiffusionPipeline(
+        pipeline = VlpnStableDiffusion(
             text_encoder=unwrapped,
             vae=self.vae,
             unet=self.unet,
             tokenizer=self.tokenizer,
-            scheduler=LMSDiscreteScheduler(
-                beta_start=0.00085, beta_end=0.012, beta_schedule="scaled_linear"
-            ),
-            safety_checker=NoCheck(),
+            scheduler=scheduler,
             feature_extractor=CLIPFeatureExtractor.from_pretrained("openai/clip-vit-base-patch32"),
         ).to(self.accelerator.device)
         pipeline.enable_attention_slicing()
 
-        data = {
-            "training": self.datamodule.train_dataloader(),
-            "validation": self.datamodule.val_dataloader(),
-        }[mode]
+        train_data = self.datamodule.train_dataloader()
+        val_data = self.datamodule.val_dataloader()
 
-        if mode == "validation" and self.stable_sample_batches > 0 and step > 0:
+        if self.stable_sample_batches > 0:
             stable_latents = torch.randn(
                 (self.sample_batch_size, pipeline.unet.in_channels, height // 8, width // 8),
                 device=pipeline.device,
@@ -387,14 +393,17 @@ class Checkpointer:
             )
 
             all_samples = []
-            filename = f"stable_step_%d.png" % (step)
+            file_path = samples_path.joinpath("stable", f"step_{step}.png")
+            file_path.parent.mkdir(parents=True, exist_ok=True)
 
-            data_enum = enumerate(data)
+            data_enum = enumerate(val_data)
 
             # Generate and save stable samples
             for i in range(0, self.stable_sample_batches):
                 prompt = [prompt for i, batch in data_enum for j, prompt in enumerate(
-                    batch["prompt"]) if i * data.batch_size + j < self.sample_batch_size]
+                    batch["prompts"]) if i * val_data.batch_size + j < self.sample_batch_size]
+
+                generator = torch.Generator(device="cuda").manual_seed(self.seed + i)
 
                 with self.accelerator.autocast():
                     samples = pipeline(
@@ -405,67 +414,64 @@ class Checkpointer:
                         guidance_scale=guidance_scale,
                         eta=eta,
                         num_inference_steps=num_inference_steps,
+                        generator=generator,
                         output_type='pil'
                     )["sample"]
 
                 all_samples += samples
+
+                del generator
                 del samples
 
             image_grid = make_grid(all_samples, self.stable_sample_batches, self.sample_batch_size)
-            image_grid.save(f"{samples_path}/{filename}")
+            image_grid.save(file_path)
 
             del all_samples
             del image_grid
             del stable_latents
 
-        all_samples = []
-        filename = f"step_%d.png" % (step)
+        for data, pool in [(val_data, "val"), (train_data, "train")]:
+            all_samples = []
+            file_path = samples_path.joinpath(pool, f"step_{step}.png")
+            file_path.parent.mkdir(parents=True, exist_ok=True)
 
-        data_enum = enumerate(data)
+            data_enum = enumerate(data)
 
-        # Generate and save random samples
-        for i in range(0, self.random_sample_batches):
-            prompt = [prompt for i, batch in data_enum for j, prompt in enumerate(
-                batch["prompt"]) if i * data.batch_size + j < self.sample_batch_size]
+            for i in range(0, self.random_sample_batches):
+                prompt = [prompt for i, batch in data_enum for j, prompt in enumerate(
+                    batch["prompts"]) if i * data.batch_size + j < self.sample_batch_size]
 
-            with self.accelerator.autocast():
-                samples = pipeline(
-                    prompt=prompt,
-                    height=self.sample_image_size,
-                    width=self.sample_image_size,
-                    guidance_scale=guidance_scale,
-                    eta=eta,
-                    num_inference_steps=num_inference_steps,
-                    output_type='pil'
-                )["sample"]
+                generator = torch.Generator(device="cuda").manual_seed(self.seed + i)
 
-            all_samples += samples
-            del samples
+                with self.accelerator.autocast():
+                    samples = pipeline(
+                        prompt=prompt,
+                        height=self.sample_image_size,
+                        width=self.sample_image_size,
+                        guidance_scale=guidance_scale,
+                        eta=eta,
+                        num_inference_steps=num_inference_steps,
+                        generator=generator,
+                        output_type='pil'
+                    )["sample"]
 
-        image_grid = make_grid(all_samples, self.random_sample_batches, self.sample_batch_size)
-        image_grid.save(f"{samples_path}/{filename}")
+                all_samples += samples
 
-        del all_samples
-        del image_grid
+                del generator
+                del samples
 
-        del checker
-        del unwrapped
-        del pipeline
-        torch.cuda.empty_cache()
+            image_grid = make_grid(all_samples, self.random_sample_batches, self.sample_batch_size)
+            image_grid.save(file_path)
 
+            del all_samples
+            del image_grid
 
-class ImageToLatents():
-    def __init__(self, vae):
-        self.vae = vae
-        self.encoded_pixel_values_cache = {}
+        del unwrapped
+        del scheduler
+        del pipeline
 
-    @torch.no_grad()
-    def __call__(self, batch):
-        key = "|".join(batch["key"])
-        if self.encoded_pixel_values_cache.get(key, None) is None:
-            self.encoded_pixel_values_cache[key] = self.vae.encode(batch["pixel_values"]).latent_dist
-        latents = self.encoded_pixel_values_cache[key].sample().detach().half() * 0.18215
-        return latents
+        if torch.cuda.is_available():
+            torch.cuda.empty_cache()
 
 
 def main():
@@ -473,17 +479,17 @@ def main():
 
     global_step_offset = 0
     if args.resume_from is not None:
-        basepath = f"{args.resume_from}"
+        basepath = Path(args.resume_from)
         print("Resuming state from %s" % args.resume_from)
-        with open(f"{basepath}/resume.json", 'r') as f:
+        with open(basepath.joinpath("resume.json"), 'r') as f:
             state = json.load(f)
         global_step_offset = state["args"].get("global_step", 0)
 
         print("We've trained %d steps so far" % global_step_offset)
     else:
         now = datetime.datetime.now().strftime("%Y-%m-%dT%H-%M-%S")
-        basepath = f"{args.output_dir}/{slugify(args.placeholder_token)}/{now}"
-        os.makedirs(basepath, exist_ok=True)
+        basepath = Path(args.output_dir).joinpath(slugify(args.placeholder_token), now)
+        basepath.mkdir(parents=True, exist_ok=True)
 
     accelerator = Accelerator(
         log_with=LoggerType.TENSORBOARD,
@@ -492,6 +498,8 @@ def main():
         mixed_precision=args.mixed_precision
     )
 
+    logging.basicConfig(filename=basepath.joinpath("log.txt"), level=logging.DEBUG)
+
     # If passed along, set the training seed now.
     if args.seed is not None:
         set_seed(args.seed)
@@ -570,8 +578,19 @@ def main():
             args.train_batch_size * accelerator.num_processes
         )
 
+    # Use 8-bit Adam for lower memory usage or to fine-tune the model in 16GB GPUs
+    if args.use_8bit_adam:
+        try:
+            import bitsandbytes as bnb
+        except ImportError:
+            raise ImportError("To use 8-bit Adam, please install the bitsandbytes library: `pip install bitsandbytes`.")
+
+        optimizer_class = bnb.optim.AdamW8bit
+    else:
+        optimizer_class = torch.optim.AdamW
+
     # Initialize the optimizer
-    optimizer = torch.optim.AdamW(
+    optimizer = optimizer_class(
         text_encoder.get_input_embeddings().parameters(),  # only optimize the embeddings
         lr=args.learning_rate,
         betas=(args.adam_beta1, args.adam_beta2),
@@ -585,7 +604,7 @@ def main():
     )
 
     datamodule = CSVDataModule(
-        data_root=args.train_data_dir, batch_size=args.train_batch_size, tokenizer=tokenizer,
+        data_file=args.train_data_file, batch_size=args.train_batch_size, tokenizer=tokenizer,
         size=args.resolution, placeholder_token=args.placeholder_token, repeats=args.repeats,
         center_crop=args.center_crop)
 
@@ -608,13 +627,12 @@ def main():
         sample_batch_size=args.sample_batch_size,
         random_sample_batches=args.random_sample_batches,
         stable_sample_batches=args.stable_sample_batches,
-        seed=args.seed
+        seed=args.seed or torch.random.seed()
     )
 
     # Scheduler and math around the number of training steps.
     overrode_max_train_steps = False
-    num_update_steps_per_epoch = math.ceil(
-        (len(train_dataloader) + len(val_dataloader)) / args.gradient_accumulation_steps)
+    num_update_steps_per_epoch = math.ceil(len(train_dataloader) / args.gradient_accumulation_steps)
     if args.max_train_steps is None:
         args.max_train_steps = args.num_train_epochs * num_update_steps_per_epoch
         overrode_max_train_steps = True
@@ -643,9 +661,10 @@ def main():
         (len(train_dataloader) + len(val_dataloader)) / args.gradient_accumulation_steps)
     if overrode_max_train_steps:
         args.max_train_steps = args.num_train_epochs * num_update_steps_per_epoch
-    # Afterwards we recalculate our number of training epochs
-    args.num_train_epochs = math.ceil(
-        args.max_train_steps / num_update_steps_per_epoch)
+
+    num_val_steps_per_epoch = len(val_dataloader)
+    num_epochs = math.ceil(args.max_train_steps / num_update_steps_per_epoch)
+    val_steps = num_val_steps_per_epoch * num_epochs
 
     # We need to initialize the trackers we use, and also store our configuration.
     # The trackers initializes automatically on the main process.
@@ -656,7 +675,7 @@ def main():
     total_batch_size = args.train_batch_size * accelerator.num_processes * args.gradient_accumulation_steps
 
     logger.info("***** Running training *****")
-    logger.info(f"  Num Epochs = {args.num_train_epochs}")
+    logger.info(f"  Num Epochs = {num_epochs}")
     logger.info(f"  Instantaneous batch size per device = {args.train_batch_size}")
     logger.info(f"  Total train batch size (w. parallel, distributed & accumulation) = {total_batch_size}")
     logger.info(f"  Gradient Accumulation steps = {args.gradient_accumulation_steps}")
@@ -666,22 +685,22 @@ def main():
     global_step = 0
     min_val_loss = np.inf
 
-    imageToLatents = ImageToLatents(vae)
-
-    checkpointer.save_samples(
-        "validation",
-        0,
-        text_encoder,
-        args.resolution, args.resolution, 7.5, 0.0, args.sample_steps)
+    if accelerator.is_main_process:
+        checkpointer.save_samples(
+            0,
+            text_encoder,
+            args.resolution, args.resolution, 7.5, 0.0, args.sample_steps)
 
-    progress_bar = tqdm(range(args.max_train_steps), disable=not accelerator.is_local_main_process)
-    progress_bar.set_description("Global steps")
+    local_progress_bar = tqdm(range(num_update_steps_per_epoch + num_val_steps_per_epoch),
+                              disable=not accelerator.is_local_main_process)
+    local_progress_bar.set_description("Batch X out of Y")
 
-    local_progress_bar = tqdm(range(num_update_steps_per_epoch), disable=not accelerator.is_local_main_process)
-    local_progress_bar.set_description("Steps")
+    global_progress_bar = tqdm(range(args.max_train_steps + val_steps), disable=not accelerator.is_local_main_process)
+    global_progress_bar.set_description("Total progress")
 
     try:
-        for epoch in range(args.num_train_epochs):
+        for epoch in range(num_epochs):
+            local_progress_bar.set_description(f"Batch {epoch + 1} out of {num_epochs}")
             local_progress_bar.reset()
 
             text_encoder.train()
@@ -689,27 +708,30 @@ def main():
 
             for step, batch in enumerate(train_dataloader):
                 with accelerator.accumulate(text_encoder):
-                    with accelerator.autocast():
-                        # Convert images to latent space
-                        latents = imageToLatents(batch)
+                    # Convert images to latent space
+                    with torch.no_grad():
+                        latents = vae.encode(batch["pixel_values"]).latent_dist.sample()
+                        latents = latents * 0.18215
 
-                        # Sample noise that we'll add to the latents
-                        noise = torch.randn(latents.shape).to(latents.device)
-                        bsz = latents.shape[0]
-                        # Sample a random timestep for each image
-                        timesteps = torch.randint(0, noise_scheduler.num_train_timesteps,
-                                                  (bsz,), device=latents.device).long()
+                    # Sample noise that we'll add to the latents
+                    noise = torch.randn(latents.shape).to(latents.device)
+                    bsz = latents.shape[0]
+                    # Sample a random timestep for each image
+                    timesteps = torch.randint(0, noise_scheduler.config.num_train_timesteps,
+                                              (bsz,), device=latents.device)
+                    timesteps = timesteps.long()
 
-                        # Add noise to the latents according to the noise magnitude at each timestep
-                        # (this is the forward diffusion process)
-                        noisy_latents = noise_scheduler.add_noise(latents, noise, timesteps)
+                    # Add noise to the latents according to the noise magnitude at each timestep
+                    # (this is the forward diffusion process)
+                    noisy_latents = noise_scheduler.add_noise(latents, noise, timesteps)
 
-                        # Get the text embedding for conditioning
-                        encoder_hidden_states = text_encoder(batch["input_ids"])[0]
+                    # Get the text embedding for conditioning
+                    encoder_hidden_states = text_encoder(batch["input_ids"])[0]
 
-                        # Predict the noise residual
-                        noise_pred = unet(noisy_latents, timesteps, encoder_hidden_states).sample
+                    # Predict the noise residual
+                    noise_pred = unet(noisy_latents, timesteps, encoder_hidden_states).sample
 
+                    with accelerator.autocast():
                         loss = F.mse_loss(noise_pred, noise, reduction="none").mean([1, 2, 3]).mean()
 
                     accelerator.backward(loss)
@@ -727,32 +749,27 @@ def main():
                     optimizer.step()
                     if not accelerator.optimizer_step_was_skipped:
                         lr_scheduler.step()
-                    optimizer.zero_grad()
+                    optimizer.zero_grad(set_to_none=True)
 
                     loss = loss.detach().item()
                     train_loss += loss
 
                 # Checks if the accelerator has performed an optimization step behind the scenes
                 if accelerator.sync_gradients:
-                    progress_bar.update(1)
                     local_progress_bar.update(1)
+                    global_progress_bar.update(1)
 
                     global_step += 1
 
                     if global_step % args.checkpoint_frequency == 0 and global_step > 0 and accelerator.is_main_process:
-                        progress_bar.clear()
                         local_progress_bar.clear()
+                        global_progress_bar.clear()
 
                         checkpointer.checkpoint(global_step + global_step_offset, "training", text_encoder)
                         save_resume_file(basepath, args, {
                             "global_step": global_step + global_step_offset,
                             "resume_checkpoint": f"{basepath}/checkpoints/last.bin"
                         })
-                        checkpointer.save_samples(
-                            "training",
-                            global_step + global_step_offset,
-                            text_encoder,
-                            args.resolution, args.resolution, 7.5, 0.0, args.sample_steps)
 
                 logs = {"mode": "training", "loss": loss, "lr": lr_scheduler.get_last_lr()[0]}
                 local_progress_bar.set_postfix(**logs)
@@ -762,17 +779,21 @@ def main():
 
             train_loss /= len(train_dataloader)
 
+            accelerator.wait_for_everyone()
+
             text_encoder.eval()
             val_loss = 0.0
 
             for step, batch in enumerate(val_dataloader):
-                with torch.no_grad(), accelerator.autocast():
-                    latents = imageToLatents(batch)
+                with torch.no_grad():
+                    latents = vae.encode(batch["pixel_values"]).latent_dist.sample()
+                    latents = latents * 0.18215
 
                     noise = torch.randn(latents.shape).to(latents.device)
                     bsz = latents.shape[0]
-                    timesteps = torch.randint(0, noise_scheduler.num_train_timesteps,
-                                              (bsz,), device=latents.device).long()
+                    timesteps = torch.randint(0, noise_scheduler.config.num_train_timesteps,
+                                              (bsz,), device=latents.device)
+                    timesteps = timesteps.long()
 
                     noisy_latents = noise_scheduler.add_noise(latents, noise, timesteps)
 
@@ -782,14 +803,15 @@ def main():
 
                     noise_pred, noise = accelerator.gather_for_metrics((noise_pred, noise))
 
-                    loss = F.mse_loss(noise_pred, noise, reduction="none").mean([1, 2, 3]).mean()
+                    with accelerator.autocast():
+                        loss = F.mse_loss(noise_pred, noise, reduction="none").mean([1, 2, 3]).mean()
 
                     loss = loss.detach().item()
                     val_loss += loss
 
                 if accelerator.sync_gradients:
-                    progress_bar.update(1)
                     local_progress_bar.update(1)
+                    global_progress_bar.update(1)
 
                 logs = {"mode": "validation", "loss": loss}
                 local_progress_bar.set_postfix(**logs)
@@ -798,21 +820,19 @@ def main():
 
             accelerator.log({"train/loss": train_loss, "val/loss": val_loss}, step=global_step)
 
-            progress_bar.clear()
             local_progress_bar.clear()
+            global_progress_bar.clear()
 
             if min_val_loss > val_loss:
                 accelerator.print(f"Validation loss reached new minimum: {min_val_loss:.2e} -> {val_loss:.2e}")
                 checkpointer.checkpoint(global_step + global_step_offset, "milestone", text_encoder)
                 min_val_loss = val_loss
 
-            checkpointer.save_samples(
-                "validation",
-                global_step + global_step_offset,
-                text_encoder,
-                args.resolution, args.resolution, 7.5, 0.0, args.sample_steps)
-
-            accelerator.wait_for_everyone()
+            if accelerator.is_main_process:
+                checkpointer.save_samples(
+                    global_step + global_step_offset,
+                    text_encoder,
+                    args.resolution, args.resolution, 7.5, 0.0, args.sample_steps)
 
         # Create the pipeline using using the trained modules and save it.
         if accelerator.is_main_process: