complete contextmanager method for keeping only one unet in GPU during training or inference

added huber loss and other schedulers

README.md

@@ -2,7 +2,9 @@
 
 ## DALL-E 2 - Pytorch (wip)
 
-Implementation of <a href="https://openai.com/dall-e-2/">DALL-E 2</a>, OpenAI's updated text-to-image synthesis neural network, in Pytorch. <a href="https://youtu.be/RJwPN4qNi_Y?t=555">Yannic Kilcher summary</a>
+Implementation of <a href="https://openai.com/dall-e-2/">DALL-E 2</a>, OpenAI's updated text-to-image synthesis neural network, in Pytorch.
+
+<a href="https://youtu.be/RJwPN4qNi_Y?t=555">Yannic Kilcher summary</a> | <a href="https://www.youtube.com/watch?v=F1X4fHzF4mQ">AssemblyAI explainer</a>
 
 The main novelty seems to be an extra layer of indirection with the prior network (whether it is an autoregressive transformer or a diffusion network), which predicts an image embedding based on the text embedding from CLIP. Specifically, this repository will only build out the diffusion prior network, as it is the best performing variant (but which incidentally involves a causal transformer as the denoising network 😂)
 
@@ -12,9 +14,7 @@ It may also explore an extension of using <a href="https://huggingface.co/spaces
 
 Please join <a href="https://discord.gg/xBPBXfcFHd"><img alt="Join us on Discord" src="https://img.shields.io/discord/823813159592001537?color=5865F2&logo=discord&logoColor=white"></a> if you are interested in helping out with the replication
 
-Do let me know if anyone is interested in a Jax version https://github.com/lucidrains/DALLE2-pytorch/discussions/8
-
-For all of you emailing me (there is a lot), the best way to contribute is through pull requests. Everything is open sourced after all. All my thoughts are public. This is your moment to participate.
+There was enough interest for a Jax version. It will be completed after the Pytorch version shows signs of life on my toy tasks. <a href="https://github.com/lucidrains/dalle2-jax">Placeholder repository</a>. I will also eventually extend this to <a href="https://github.com/lucidrains/dalle2-video">text to video</a>, once the repository is in a good place.
 
 ## Install
 
@@ -22,19 +22,11 @@ For all of you emailing me (there is a lot), the best way to contribute is throu
 $ pip install dalle2-pytorch
 ```
 
-## CLI Usage (work in progress)
-
-```bash
-$ dream 'sharing a sunset at the summit of mount everest with my dog'
-```
-
-Once built, images will be saved to the same directory the command is invoked
-
-## Training (for deep learning practitioners)
+## Usage
 
 To train DALLE-2 is a 3 step process, with the training of CLIP being the most important
 
-To train CLIP, you can either use `x-clip` package, or join the LAION discord, where a lot of replication efforts are already underway.
+To train CLIP, you can either use <a href="https://github.com/lucidrains/x-clip">x-clip</a> package, or join the LAION discord, where a lot of replication efforts are already <a href="https://github.com/mlfoundations/open_clip">underway</a>.
 
 This repository will demonstrate integration with `x-clip` for starters
 
@@ -109,7 +101,7 @@ clip = CLIP(
 unet = Unet(
     dim = 128,
     image_embed_dim = 512,
-    time_dim = 128,
+    cond_dim = 128,
     channels = 3,
     dim_mults=(1, 2, 4, 8)
 ).cuda()
@@ -117,7 +109,7 @@ unet = Unet(
 # decoder, which contains the unet and clip
 
 decoder = Decoder(
-    net = unet,
+    unet = unet,
     clip = clip,
     timesteps = 100,
     cond_drop_prob = 0.2
@@ -136,12 +128,14 @@ loss.backward()
 # then it will learn to generate images based on the CLIP image embeddings
 ```
 
-Finally, the main contribution of the paper. The repository offers the diffusion prior network. It takes the CLIP text embeddings and tries to generate the CLIP image embeddings. Again, you will need the trained CLIP fron the first step
+Finally, the main contribution of the paper. The repository offers the diffusion prior network. It takes the CLIP text embeddings and tries to generate the CLIP image embeddings. Again, you will need the trained CLIP from the first step
 
 ```python
 import torch
 from dalle2_pytorch import DiffusionPriorNetwork, DiffusionPrior, CLIP
 
+# get trained CLIP from step one
+
 clip = CLIP(
     dim_text = 512,
     dim_image = 512,
@@ -160,7 +154,6 @@ clip = CLIP(
 
 prior_network = DiffusionPriorNetwork(
     dim = 512,
-    num_timesteps = 100,
     depth = 6,
     dim_head = 64,
     heads = 8
@@ -189,7 +182,82 @@ loss.backward()
 # now the diffusion prior can generate image embeddings from the text embeddings
 ```
 
-Finally, to generate the DALL-E2 images from text. Insert the trained `DiffusionPrior` as well as the `Decoder` (which both contains `CLIP`, a unet, and a causal transformer)
+In the paper, they actually used a <a href="https://cascaded-diffusion.github.io/">recently discovered technique</a>, from <a href="http://www.jonathanho.me/">Jonathan Ho</a> himself (original author of DDPMs, the core technique used in DALL-E v2) for high resolution image synthesis.
+
+This can easily be used within this framework as so
+
+```python
+import torch
+from dalle2_pytorch import Unet, Decoder, CLIP
+
+# trained clip from step 1
+
+clip = CLIP(
+    dim_text = 512,
+    dim_image = 512,
+    dim_latent = 512,
+    num_text_tokens = 49408,
+    text_enc_depth = 6,
+    text_seq_len = 256,
+    text_heads = 8,
+    visual_enc_depth = 6,
+    visual_image_size = 256,
+    visual_patch_size = 32,
+    visual_heads = 8
+).cuda()
+
+# 2 unets for the decoder (a la cascading DDPM)
+
+unet1 = Unet(
+    dim = 32,
+    image_embed_dim = 512,
+    cond_dim = 128,
+    channels = 3,
+    dim_mults = (1, 2, 4, 8)
+).cuda()
+
+unet2 = Unet(
+    dim = 32,
+    image_embed_dim = 512,
+    cond_dim = 128,
+    channels = 3,
+    dim_mults = (1, 2, 4, 8, 16)
+).cuda()
+
+# decoder, which contains the unet(s) and clip
+
+decoder = Decoder(
+    clip = clip,
+    unet = (unet1, unet2),            # insert both unets in order of low resolution to highest resolution (you can have as many stages as you want here)
+    image_sizes = (256, 512),         # resolutions, 256 for first unet, 512 for second. these must be unique and in ascending order (matches with the unets passed in)
+    timesteps = 1000,
+    cond_drop_prob = 0.2
+).cuda()
+
+# mock images (get a lot of this)
+
+images = torch.randn(4, 3, 512, 512).cuda()
+
+# feed images into decoder, specifying which unet you want to train
+# each unet can be trained separately, which is one of the benefits of the cascading DDPM scheme
+
+loss = decoder(images, unet_number = 1)
+loss.backward()
+
+loss = decoder(images, unet_number = 2)
+loss.backward()
+
+# do the above for many steps for both unets
+
+# then it will learn to generate images based on the CLIP image embeddings
+
+# chaining the unets from lowest resolution to highest resolution (thus cascading)
+
+mock_image_embed = torch.randn(1, 512).cuda()
+images = decoder.sample(mock_image_embed) # (1, 3, 512, 512)
+```
+
+Finally, to generate the DALL-E2 images from text. Insert the trained `DiffusionPrior` as well as the `Decoder` (which wraps `CLIP`, the causal transformer, and unet(s))
 
 ```python
 from dalle2_pytorch import DALLE2
@@ -249,7 +317,6 @@ loss.backward()
 
 prior_network = DiffusionPriorNetwork(
     dim = 512,
-    num_timesteps = 100,
     depth = 6,
     dim_head = 64,
     heads = 8
@@ -269,23 +336,33 @@ loss.backward()
 
 # decoder (with unet)
 
-unet = Unet(
+unet1 = Unet(
     dim = 128,
     image_embed_dim = 512,
-    time_dim = 128,
+    cond_dim = 128,
     channels = 3,
     dim_mults=(1, 2, 4, 8)
 ).cuda()
 
+unet2 = Unet(
+    dim = 16,
+    image_embed_dim = 512,
+    cond_dim = 128,
+    channels = 3,
+    dim_mults = (1, 2, 4, 8, 16)
+).cuda()
+
 decoder = Decoder(
-    net = unet,
+    unet = (unet1, unet2),
+    image_sizes = (128, 256),
     clip = clip,
     timesteps = 100,
     cond_drop_prob = 0.2
 ).cuda()
 
-loss = decoder(images)
-loss.backward()
+for unet_number in (1, 2):
+    loss = decoder(images, unet_number = unet_number) # this can optionally be decoder(images, text) if you wish to condition on the text encodings as well, though it was hinted in the paper it didn't do much
+    loss.backward()
 
 # do above for many steps
 
@@ -294,15 +371,32 @@ dalle2 = DALLE2(
     decoder = decoder
 )
 
-images = dalle2(['cute puppy chasing after a squirrel'])
+images = dalle2(
+    ['cute puppy chasing after a squirrel'],
+    cond_scale = 2. # classifier free guidance strength (> 1 would strengthen the condition)
+)
 
-# save your image
+# save your image (in this example, of size 256x256)
 ```
 
 Everything in this readme should run without error
 
+You can also train the decoder on images of greater than the size (say 512x512) at which CLIP was trained (256x256). The images will be resized to CLIP image resolution for the image embeddings
+
 For the layperson, no worries, training will all be automated into a CLI tool, at least for small scale training.
 
+## CLI Usage (work in progress)
+
+```bash
+$ dream 'sharing a sunset at the summit of mount everest with my dog'
+```
+
+Once built, images will be saved to the same directory the command is invoked
+
+## Training wrapper (wip)
+
+Offer training wrappers
+
 ## Training CLI (wip)
 
 <a href="https://github.com/lucidrains/stylegan2-pytorch">template</a>
@@ -312,11 +406,15 @@ For the layperson, no worries, training will all be automated into a CLI tool, a
 - [x] finish off gaussian diffusion class for latent embedding - allow for prediction of epsilon
 - [x] add what was proposed in the paper, where DDPM objective for image latent embedding predicts x0 directly (reread vq-diffusion paper and get caught up on that line of work)
 - [x] make sure it works end to end to produce an output tensor, taking a single gradient step
-- [ ] augment unet so that it can also be conditioned on text encodings (although in paper they hinted this didn't make much a difference)
-- [ ] look into Jonathan Ho's cascading DDPM for the decoder, as that seems to be what they are using. get caught up on DDPM literature
-- [ ] figure out all the current bag of tricks needed to make DDPMs great (starting with the blur trick mentioned in paper)
+- [x] augment unet so that it can also be conditioned on text encodings (although in paper they hinted this didn't make much a difference)
+- [x] figure out all the current bag of tricks needed to make DDPMs great (starting with the blur trick mentioned in paper)
+- [x] build the cascading ddpm by having Decoder class manage multiple unets at different resolutions
+- [x] add efficient attention in unet
+- [x] be able to finely customize what to condition on (text, image embed) for specific unet in the cascade (super resolution ddpms near the end may not need too much conditioning)
+- [x] offload unets not being trained on to CPU for memory efficiency (for training each resolution unets separately)
+- [ ] build out latent diffusion architecture in separate file, as it is not faithful to dalle-2 (but offer it as as setting)
+- [ ] become an expert with unets, cleanup unet code, make it fully configurable, port all learnings over to https://github.com/lucidrains/x-unet
 - [ ] train on a toy task, offer in colab
-- [ ] add attention to unet - apply some personal tricks with efficient attention
 
 ## Citations
 
@@ -365,4 +463,12 @@ For the layperson, no worries, training will all be automated into a CLI tool, a
 }
 ```
 
+```bibtex
+@inproceedings{Tu2022MaxViTMV,
+    title   = {MaxViT: Multi-Axis Vision Transformer},
+    author  = {Zhe-Wei Tu and Hossein Talebi and Han Zhang and Feng Yang and Peyman Milanfar and Alan Conrad Bovik and Yinxiao Li},
+    year    = {2022}
+}
+```
+
 *Creating noise from data is easy; creating data from noise is generative modeling.* - Yang Song's <a href="https://arxiv.org/abs/2011.13456">paper</a>

dalle2_pytorch/cli.py

@@ -6,4 +6,4 @@ def main():
 @click.command()
 @click.argument('text')
 def dream(text):
-    return image
+    return 'not ready yet'

dalle2_pytorch/latent_diffusion.py

@@ -0,0 +1,12 @@
+import torch
+import torch.nn.functional as F
+from torch import nn, einsum
+
+from einops import rearrange
+
+class LatentDiffusion(nn.Module):
+    def __init__(self):
+        super().__init__()
+
+    def forward(self, x):
+        return x

setup.py

@@ -10,7 +10,7 @@ setup(
       'dream = dalle2_pytorch.cli:dream'
     ],
   },
-  version = '0.0.6',
+  version = '0.0.28',
   license='MIT',
   description = 'DALL-E 2',
   author = 'Phil Wang',
@@ -25,6 +25,7 @@ setup(
     'click',
     'einops>=0.4',
     'einops-exts>=0.0.3',
+    'kornia>=0.5.4',
     'pillow',
     'torch>=1.10',
     'torchvision',