switch to using linear attention for the sparse attention layers within unet, given success in GAN projects

update deps, commit to using webdatasets, per @rom1504 consultation
just clip the diffusion prior network parameters
2026-02-12 19:44:26 +01:00 · 2022-05-01 17:59:03 -07:00 · 2022-05-01 12:22:15 -07:00 · 2022-05-01 12:01:08 -07:00 · 2022-05-01 11:57:08 -07:00 · 2022-05-01 11:55:38 -07:00
10 changed files with 1365 additions and 293 deletions
--- a/README.md
+++ b/README.md
@@ -47,7 +47,7 @@ clip = CLIP(
    use_all_token_embeds = True,            # whether to use fine-grained contrastive learning (FILIP)
    decoupled_contrastive_learning = True,  # use decoupled contrastive learning (DCL) objective function, removing positive pairs from the denominator of the InfoNCE loss (CLOOB + DCL)
    extra_latent_projection = True,         # whether to use separate projections for text-to-image vs image-to-text comparisons (CLOOB)
-    use_visual_ssl = True,                  # whether to do self supervised learning on iages
+    use_visual_ssl = True,                  # whether to do self supervised learning on images
    visual_ssl_type = 'simclr',             # can be either 'simclr' or 'simsiam', depending on using DeCLIP or SLIP
    use_mlm = False,                        # use masked language learning (MLM) on text (DeCLIP)
    text_ssl_loss_weight = 0.05,            # weight for text MLM loss
@@ -110,7 +110,8 @@ decoder = Decoder(
    unet = unet,
    clip = clip,
    timesteps = 100,
-    cond_drop_prob = 0.2
+    image_cond_drop_prob = 0.1,
+    text_cond_drop_prob = 0.5
 ).cuda()

 # mock images (get a lot of this)
@@ -229,7 +230,8 @@ decoder = Decoder(
    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
+    image_cond_drop_prob = 0.1,
+    text_cond_drop_prob = 0.5
 ).cuda()

 # mock images (get a lot of this)
@@ -348,7 +350,8 @@ decoder = Decoder(
    image_sizes = (128, 256),
    clip = clip,
    timesteps = 100,
-    cond_drop_prob = 0.2,
+    image_cond_drop_prob = 0.1,
+    text_cond_drop_prob = 0.5,
    condition_on_text_encodings = False  # set this to True if you wish to condition on text during training and sampling
 ).cuda()

@@ -430,8 +433,8 @@ images = torch.randn(4, 3, 256, 256).cuda()
 # precompute the text and image embeddings
 # here using the diffusion prior class, but could be done with CLIP alone

-clip_image_embeds = diffusion_prior.get_image_embed(images)
-clip_text_embeds = diffusion_prior.get_text_cond(text).get('text_embed')
+clip_image_embeds = diffusion_prior.clip.embed_image(images).image_embed
+clip_text_embeds = diffusion_prior.clip.embed_text(text).text_embed

 # feed text and images into diffusion prior network

@@ -495,14 +498,105 @@ loss.backward()
 # now the diffusion prior can generate image embeddings from the text embeddings
 ```

+## OpenAI CLIP
+
+Although there is the possibility they are using an unreleased, more powerful CLIP, you can use one of the released ones, if you do not wish to train your own CLIP from scratch. This will also allow the community to more quickly validate the conclusions of the paper.
+
+To use a pretrained OpenAI CLIP, simply import `OpenAIClipAdapter` and pass it into the `DiffusionPrior` or `Decoder` like so
+
+```python
+import torch
+from dalle2_pytorch import DALLE2, DiffusionPriorNetwork, DiffusionPrior, Unet, Decoder, OpenAIClipAdapter
+
+# openai pretrained clip - defaults to ViT/B-32
+
+clip = OpenAIClipAdapter()
+
+# mock data
+
+text = torch.randint(0, 49408, (4, 256)).cuda()
+images = torch.randn(4, 3, 256, 256).cuda()
+
+# prior networks (with transformer)
+
+prior_network = DiffusionPriorNetwork(
+    dim = 512,
+    depth = 6,
+    dim_head = 64,
+    heads = 8
+).cuda()
+
+diffusion_prior = DiffusionPrior(
+    net = prior_network,
+    clip = clip,
+    timesteps = 100,
+    cond_drop_prob = 0.2
+).cuda()
+
+loss = diffusion_prior(text, images)
+loss.backward()
+
+# do above for many steps ...
+
+# decoder (with unet)
+
+unet1 = Unet(
+    dim = 128,
+    image_embed_dim = 512,
+    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(
+    unet = (unet1, unet2),
+    image_sizes = (128, 256),
+    clip = clip,
+    timesteps = 100,
+    image_cond_drop_prob = 0.1,
+    text_cond_drop_prob = 0.5,
+    condition_on_text_encodings = False  # set this to True if you wish to condition on text during training and sampling
+).cuda()
+
+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
+
+dalle2 = DALLE2(
+    prior = diffusion_prior,
+    decoder = decoder
+)
+
+images = dalle2(
+    ['a butterfly trying to escape a tornado'],
+    cond_scale = 2. # classifier free guidance strength (> 1 would strengthen the condition)
+)
+
+# save your image (in this example, of size 256x256)
+```
+
+Now you'll just have to worry about training the Prior and the Decoder!
+
 ## Experimental

 ### DALL-E2 with Latent Diffusion

-This repository decides to take the next step and offer DALL-E2 combined with <a href="https://huggingface.co/spaces/multimodalart/latentdiffusion">latent diffusion</a>, from Rombach et al.
+This repository decides to take the next step and offer DALL-E v2 combined with <a href="https://huggingface.co/spaces/multimodalart/latentdiffusion">latent diffusion</a>, from Rombach et al.

 You can use it as follows. Latent diffusion can be limited to just the first U-Net in the cascade, or to any number you wish.

+The repository also comes equipped with all the necessary settings to recreate `ViT-VQGan` from the <a href="https://arxiv.org/abs/2110.04627">Improved VQGans</a> paper. Furthermore, the <a href="https://github.com/lucidrains/vector-quantize-pytorch">vector quantization</a> library also comes equipped to do <a href="https://arxiv.org/abs/2203.01941">residual or multi-headed quantization</a>, which I believe will give an even further boost in performance to the autoencoder.
+
 ```python
 import torch
 from dalle2_pytorch import Unet, Decoder, CLIP, VQGanVAE
@@ -526,7 +620,7 @@ clip = CLIP(
 # 3 unets for the decoder (a la cascading DDPM)

 # first two unets are doing latent diffusion
-# vqgan-vae must be trained before hand
+# vqgan-vae must be trained beforehand

 vae1 = VQGanVAE(
    dim = 32,
@@ -579,7 +673,8 @@ decoder = Decoder(
    unet = (unet1, unet2, unet3),      # insert unets in order of low resolution to highest resolution (you can have as many stages as you want here)
    image_sizes = (256, 512, 1024),    # resolutions, 256 for first unet, 512 for second, 1024 for third
    timesteps = 100,
-    cond_drop_prob = 0.2
+    image_cond_drop_prob = 0.1,
+    text_cond_drop_prob = 0.5
 ).cuda()

 # mock images (get a lot of this)
@@ -613,7 +708,83 @@ images = decoder.sample(mock_image_embed) # (1, 3, 1024, 1024)

 ## Training wrapper (wip)

-Offer training wrappers
+### Decoder Training
+
+Training the `Decoder` may be confusing, as one needs to keep track of an optimizer for each of the `Unet`(s) separately. Each `Unet` will also need its own corresponding exponential moving average. The `DecoderTrainer` hopes to make this simple, as shown below
+
+```python
+import torch
+from dalle2_pytorch import DALLE2, Unet, Decoder, CLIP, DecoderTrainer
+
+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()
+
+# mock data
+
+text = torch.randint(0, 49408, (4, 256)).cuda()
+images = torch.randn(4, 3, 256, 256).cuda()
+
+# decoder (with unet)
+
+unet1 = Unet(
+    dim = 128,
+    image_embed_dim = 512,
+    text_embed_dim = 512,
+    cond_dim = 128,
+    channels = 3,
+    dim_mults=(1, 2, 4, 8)
+).cuda()
+
+unet2 = Unet(
+    dim = 16,
+    image_embed_dim = 512,
+    text_embed_dim = 512,
+    cond_dim = 128,
+    channels = 3,
+    dim_mults = (1, 2, 4, 8, 16),
+    cond_on_text_encodings = True
+).cuda()
+
+decoder = Decoder(
+    unet = (unet1, unet2),
+    image_sizes = (128, 256),
+    clip = clip,
+    timesteps = 1000,
+    condition_on_text_encodings = True
+).cuda()
+
+decoder_trainer = DecoderTrainer(
+    decoder,
+    lr = 3e-4,
+    wd = 1e-2,
+    ema_beta = 0.99,
+    ema_update_after_step = 1000,
+    ema_update_every = 10,
+)
+
+for unet_number in (1, 2):
+    loss = decoder_trainer(images, text = text, unet_number = unet_number)  # use the decoder_trainer forward
+    loss.backward()
+
+    decoder_trainer.update(unet_number) # update the specific unet as well as its exponential moving average
+
+# after much training
+# you can sample from the exponentially moving averaged unets as so
+
+mock_image_embed = torch.randn(4, 512).cuda()
+images = decoder_trainer.sample(mock_image_embed, text = text) # (4, 3, 256, 256)
+```

 ## CLI (wip)

@@ -645,13 +816,20 @@ Once built, images will be saved to the same directory the command is invoked
 - [x] use attention-based upsampling https://arxiv.org/abs/2112.11435
 - [x] use inheritance just this once for sharing logic between decoder and prior network ddpms
 - [x] bring in vit-vqgan https://arxiv.org/abs/2110.04627 for the latent diffusion
- [ ] abstract interface for CLIP adapter class, so other CLIPs can be brought in
+- [x] abstract interface for CLIP adapter class, so other CLIPs can be brought in
+- [x] take care of mixed precision as well as gradient accumulation within decoder trainer
+- [x] just take care of the training for the decoder in a wrapper class, as each unet in the cascade will need its own optimizer
+- [x] bring in tools to train vqgan-vae
+- [x] add convnext backbone for vqgan-vae (in addition to vit [vit-vqgan] + resnet)
 - [ ] become an expert with unets, cleanup unet code, make it fully configurable, port all learnings over to https://github.com/lucidrains/x-unet
 - [ ] copy the cascading ddpm code to a separate repo (perhaps https://github.com/lucidrains/denoising-diffusion-pytorch) as the main contribution of dalle2 really is just the prior network
 - [ ] transcribe code to Jax, which lowers the activation energy for distributed training, given access to TPUs
+- [ ] pull logic for training diffusion prior into a class DiffusionPriorTrainer, for eventual script based + CLI based training
 - [ ] train on a toy task, offer in colab
+- [ ] think about how best to design a declarative training config that handles preencoding for prior and training of multiple networks in decoder
 - [ ] extend diffusion head to use diffusion-gan (potentially using lightweight-gan) to speed up inference
- [ ] bring in tools to train vqgan-vae
+- [ ] bring in cross-scale embedding from iclr paper https://github.com/lucidrains/vit-pytorch/blob/main/vit_pytorch/crossformer.py#L14
+- [ ] figure out if possible to augment with external memory, as described in https://arxiv.org/abs/2204.11824

 ## Citations

@@ -683,12 +861,22 @@ Once built, images will be saved to the same directory the command is invoked

 ```bibtex
@inproceedings{Liu2022ACF,
-    title   = {A ConvNet for the 2020https://arxiv.org/abs/2112.11435s},
+    title   = {A ConvNet for the 2020s},
    author  = {Zhuang Liu and Hanzi Mao and Chaozheng Wu and Christoph Feichtenhofer and Trevor Darrell and Saining Xie},
    year    = {2022}
 }
 ```

+```bibtex
+@article{shen2019efficient,
+    author  = {Zhuoran Shen and Mingyuan Zhang and Haiyu Zhao and Shuai Yi and Hongsheng Li},
+    title   = {Efficient Attention: Attention with Linear Complexities},
+    journal = {CoRR},
+    year    = {2018},
+    url     = {http://arxiv.org/abs/1812.01243},
+}
+```
+
 ```bibtex
@inproceedings{Tu2022MaxViTMV,
    title   = {MaxViT: Multi-Axis Vision Transformer},
@@ -697,16 +885,6 @@ Once built, images will be saved to the same directory the command is invoked
 }
 ```

-```bibtex
-@article{Arar2021LearnedQF,
-    title   = {Learned Queries for Efficient Local Attention},
-    author  = {Moab Arar and Ariel Shamir and Amit H. Bermano},
-    journal = {ArXiv},
-    year    = {2021},
-    volume  = {abs/2112.11435}
-}
-```
-
 ```bibtex
@article{Yu2021VectorquantizedIM,
    title   = {Vector-quantized Image Modeling with Improved VQGAN},
--- a/dalle2_pytorch/init.py
+++ b/dalle2_pytorch/init.py
@@ -1,4 +1,6 @@
 from dalle2_pytorch.dalle2_pytorch import DALLE2, DiffusionPriorNetwork, DiffusionPrior, Unet, Decoder
+from dalle2_pytorch.dalle2_pytorch import OpenAIClipAdapter
+from dalle2_pytorch.train import DecoderTrainer

 from dalle2_pytorch.vqgan_vae import VQGanVAE
 from x_clip import CLIP
--- a/dalle2_pytorch/attention.py
+++ b/dalle2_pytorch/attention.py
@@ -1,130 +0,0 @@
-import torch
-from torch import nn, einsum
-import torch.nn.functional as F
-
-from einops import rearrange, repeat
-
-class LayerNormChan(nn.Module):
-    def __init__(
-        self,
-        dim,
-        eps = 1e-5
-    ):
-        super().__init__()
-        self.eps = eps
-        self.gamma = nn.Parameter(torch.ones(1, dim, 1, 1))
-
-    def forward(self, x):
-        var = torch.var(x, dim = 1, unbiased = False, keepdim = True)
-        mean = torch.mean(x, dim = 1, keepdim = True)
-        return (x - mean) / (var + self.eps).sqrt() * self.gamma
-
-# attention-based upsampling
-# from https://arxiv.org/abs/2112.11435
-
-class QueryAndAttend(nn.Module):
-    def __init__(
-        self,
-        *,
-        dim,
-        num_queries = 1,
-        dim_head = 32,
-        heads = 8,
-        window_size = 3
-    ):
-        super().__init__()
-        self.scale = dim_head ** -0.5
-        inner_dim = dim_head * heads
-        self.heads = heads
-        self.dim_head = dim_head
-        self.window_size = window_size
-        self.num_queries = num_queries
-
-        self.rel_pos_bias = nn.Parameter(torch.randn(heads, num_queries, window_size * window_size, 1, 1))
-
-        self.queries = nn.Parameter(torch.randn(heads, num_queries, dim_head))
-        self.to_kv = nn.Conv2d(dim, dim_head * 2, 1, bias = False)
-
-        self.to_out = nn.Sequential(
-            nn.Conv2d(inner_dim, dim * 2, 1, bias = False),
-            nn.Tanh(),
-            nn.Conv2d(dim * 2, dim, 1, bias = False)
-        )
-
-    def forward(self, x):
-        """
-        einstein notation
-        b - batch
-        h - heads
-        l - num queries
-        d - head dimension
-        x - height
-        y - width
-        j - source sequence for attending to (kernel size squared in this case)
-        """
-
-        wsz, heads, dim_head, num_queries = self.window_size, self.heads, self.dim_head, self.num_queries
-        batch, _, height, width = x.shape
-
-        is_one_query = self.num_queries == 1
-
-        # queries, keys, values
-
-        q = self.queries * self.scale
-        k, v = self.to_kv(x).chunk(2, dim = 1)
-
-        # similarities
-
-        sim = einsum('h l d, b d x y -> b h l x y', q, k)
-        sim = rearrange(sim, 'b ... x y -> b (...) x y')
-
-        # unfold the similarity scores, with float(-inf) as padding value
-
-        mask_value = -torch.finfo(sim.dtype).max
-        sim = F.pad(sim, ((wsz // 2,) * 4), value = mask_value)
-        sim = F.unfold(sim, kernel_size = wsz)
-        sim = rearrange(sim, 'b (h l j) (x y) -> b h l j x y', h = heads, l = num_queries, x = height, y = width)
-
-        # rel pos bias
-
-        sim = sim + self.rel_pos_bias
-
-        # numerically stable attention
-
-        sim = sim - sim.amax(dim = -3, keepdim = True).detach()
-        attn = sim.softmax(dim = -3)
-
-        # unfold values
-
-        v = F.pad(v, ((wsz // 2,) * 4), value = 0.)
-        v = F.unfold(v, kernel_size = wsz)
-        v = rearrange(v, 'b (d j) (x y) -> b d j x y', d = dim_head, x = height, y = width)
-
-        # aggregate values
-
-        out = einsum('b h l j x y, b d j x y -> b l h d x y', attn, v)
-
-        # combine heads
-
-        out = rearrange(out, 'b l h d x y -> (b l) (h d) x y')
-        out = self.to_out(out)
-        out = rearrange(out, '(b l) d x y -> b l d x y', b = batch)
-
-        # return original input if one query
-
-        if is_one_query:
-            out = rearrange(out, 'b 1 ... -> b ...')
-
-        return out
-
-class QueryAttnUpsample(nn.Module):
-    def __init__(self, dim, **kwargs):
-        super().__init__()
-        self.norm = LayerNormChan(dim)
-        self.qna = QueryAndAttend(dim = dim, num_queries = 4, **kwargs)
-
-    def forward(self, x):
-        x = self.norm(x)
-        out = self.qna(x)
-        out = rearrange(out, 'b (w1 w2) c h w -> b c (h w1) (w w2)', w1 = 2, w2 = 2)
-        return out
--- a/dalle2_pytorch/dalle2_pytorch.py
+++ b/dalle2_pytorch/dalle2_pytorch.py
@@ -3,10 +3,12 @@ from tqdm import tqdm
 from inspect import isfunction
 from functools import partial
 from contextlib import contextmanager
+from collections import namedtuple

 import torch
 import torch.nn.functional as F
 from torch import nn, einsum
+import torchvision.transforms as T

 from einops import rearrange, repeat
 from einops.layers.torch import Rearrange
@@ -17,7 +19,6 @@ from kornia.filters import gaussian_blur2d

 from dalle2_pytorch.tokenizer import tokenizer
 from dalle2_pytorch.vqgan_vae import NullVQGanVAE, VQGanVAE
-from dalle2_pytorch.attention import QueryAttnUpsample

 # use x-clip

@@ -36,6 +37,10 @@ def default(val, d):
 def cast_tuple(val, length = 1):
    return val if isinstance(val, tuple) else ((val,) * length)

+@contextmanager
+def null_context(*args, **kwargs):
+    yield
+
 def eval_decorator(fn):
    def inner(model, *args, **kwargs):
        was_training = model.training
@@ -86,6 +91,144 @@ def resize_image_to(t, image_size, mode = 'bilinear'): # take a look at https://

    return F.interpolate(t, size = shape, mode = mode, align_corners = False)

+# image normalization functions
+# ddpms expect images to be in the range of -1 to 1
+# but CLIP may otherwise
+
+def normalize_img(img):
+    return img * 2 - 1
+
+def unnormalize_img(normed_img):
+    return (normed_img + 1) * 0.5
+
+# clip related adapters
+
+EmbeddedText = namedtuple('EmbedTextReturn', ['text_embed', 'text_encodings', 'text_mask'])
+EmbeddedImage = namedtuple('EmbedImageReturn', ['image_embed', 'image_encodings'])
+
+class BaseClipAdapter(nn.Module):
+    def __init__(self, clip):
+        super().__init__()
+        self.clip = clip
+
+    @property
+    def dim_latent(self):
+        raise NotImplementedError
+
+    @property
+    def image_size(self):
+        raise NotImplementedError
+
+    @property
+    def image_channels(self):
+        raise NotImplementedError
+
+    @property
+    def max_text_len(self):
+        raise NotImplementedError
+
+    def embed_text(self, text):
+        raise NotImplementedError
+
+    def embed_image(self, image):
+        raise NotImplementedError
+
+class XClipAdapter(BaseClipAdapter):
+    @property
+    def dim_latent(self):
+        return self.clip.dim_latent
+
+    @property
+    def image_size(self):
+        return self.clip.image_size
+
+    @property
+    def image_channels(self):
+        return self.clip.image_channels
+
+    @property
+    def max_text_len(self):
+        return self.clip.text_seq_len
+
+    @torch.no_grad()
+    def embed_text(self, text):
+        text = text[..., :self.max_text_len]
+        text_mask = text != 0
+        encoder_output = self.clip.text_transformer(text)
+        text_cls, text_encodings = encoder_output[:, 0], encoder_output[:, 1:]
+        text_embed = self.clip.to_text_latent(text_cls)
+        return EmbeddedText(l2norm(text_embed), text_encodings, text_mask)
+
+    @torch.no_grad()
+    def embed_image(self, image):
+        image = resize_image_to(image, self.image_size)
+        encoder_output = self.clip.visual_transformer(image)
+        image_cls, image_encodings = encoder_output[:, 0], encoder_output[:, 1:]
+        image_embed = self.clip.to_visual_latent(image_cls)
+        return EmbeddedImage(l2norm(image_embed), image_encodings)
+
+class OpenAIClipAdapter(BaseClipAdapter):
+    def __init__(
+        self,
+        name = 'ViT-B/32'
+    ):
+        import clip
+        openai_clip, preprocess = clip.load(name)
+        super().__init__(openai_clip)
+
+        text_attention_final = self.find_layer('ln_final')
+        self.handle = text_attention_final.register_forward_hook(self._hook)
+        self.clip_normalize = preprocess.transforms[-1]
+        self.cleared = False
+
+    def find_layer(self,  layer):
+        modules = dict([*self.clip.named_modules()])
+        return modules.get(layer, None)
+
+    def clear(self):
+        if self.cleared:
+            return
+
+        self.handle()
+
+    def _hook(self, _, inputs, outputs):
+        self.text_encodings = outputs
+
+    @property
+    def dim_latent(self):
+        return 512
+
+    @property
+    def image_size(self):
+        return self.clip.visual.input_resolution
+
+    @property
+    def image_channels(self):
+        return 3
+
+    @property
+    def max_text_len(self):
+        return self.clip.context_length
+
+    @torch.no_grad()
+    def embed_text(self, text):
+        text = text[..., :self.max_text_len]
+        text_mask = text != 0
+        assert not self.cleared
+
+        text_embed = self.clip.encode_text(text)
+        text_encodings = self.text_encodings
+        del self.text_encodings
+        return EmbeddedText(text_embed.float(), text_encodings.float(), text_mask)
+
+    @torch.no_grad()
+    def embed_image(self, image):
+        assert not self.cleared
+        image = resize_image_to(image, self.image_size)
+        image = self.clip_normalize(unnormalize_img(image))
+        image_embed = self.clip.encode_image(image)
+        return EmbeddedImage(image_embed.float(), None)
+
 # classifier free guidance functions

 def prob_mask_like(shape, prob, device):
@@ -166,7 +309,18 @@ class BaseGaussianDiffusion(nn.Module):

        timesteps, = betas.shape
        self.num_timesteps = int(timesteps)
+
+        if loss_type == 'l1':
+            loss_fn = F.l1_loss
+        elif loss_type == 'l2':
+            loss_fn = F.mse_loss
+        elif loss_type == 'huber':
+            loss_fn = F.smooth_l1_loss
+        else:
+            raise NotImplementedError()
+
        self.loss_type = loss_type
+        self.loss_fn = loss_fn

        self.register_buffer('betas', betas)
        self.register_buffer('alphas_cumprod', alphas_cumprod)
@@ -530,14 +684,14 @@ class DiffusionPriorNetwork(nn.Module):

        # classifier free guidance

-        cond_prob_mask = prob_mask_like((batch,), cond_drop_prob, device = device)
-        cond_prob_mask = rearrange(cond_prob_mask, 'b -> b 1')
+        keep_mask = prob_mask_like((batch,), 1 - cond_drop_prob, device = device)
+        keep_mask = rearrange(keep_mask, 'b -> b 1')

-        mask &= cond_prob_mask
+        mask &= keep_mask

        # whether text embedding is masked or not depends on the classifier free guidance conditional masking

-        mask = torch.cat((mask, cond_prob_mask), dim = 1)
+        mask = torch.cat((mask, keep_mask), dim = 1)

        # whether text embedding is used for conditioning depends on whether text encodings are available for attention (for classifier free guidance, even though it seems from the paper it was not used in the prior ddpm, as the objective is different)
        # but let's just do it right
@@ -582,6 +736,7 @@ class DiffusionPrior(BaseGaussianDiffusion):
        predict_x_start = True,
        beta_schedule = "cosine",
        condition_on_text_encodings = True, # the paper suggests this is needed, but you can turn it off for your CLIP preprocessed text embed -> image embed training
+        sampling_clamp_l2norm = False
    ):
        super().__init__(
            beta_schedule = beta_schedule,
@@ -590,7 +745,10 @@ class DiffusionPrior(BaseGaussianDiffusion):
        )

        if exists(clip):
-            assert isinstance(clip, CLIP)
+            if isinstance(clip, CLIP):
+                clip = XClipAdapter(clip)
+
+            assert isinstance(clip, BaseClipAdapter)
            freeze_model_and_make_eval_(clip)
            self.clip = clip
        else:
@@ -607,28 +765,8 @@ class DiffusionPrior(BaseGaussianDiffusion):
        self.predict_x_start = predict_x_start
        # in paper, they do not predict the noise, but predict x0 directly for image embedding, claiming empirically better results. I'll just offer both.

-    @torch.no_grad()
-    def get_image_embed(self, image):
-        assert exists(self.clip)
-
-        image_encoding = self.clip.visual_transformer(image)
-        image_cls = image_encoding[:, 0]
-        image_embed = self.clip.to_visual_latent(image_cls)
-        return l2norm(image_embed)
-
-    @torch.no_grad()
-    def get_text_cond(self, text):
-        assert exists(self.clip)
-
-        text_encodings = self.clip.text_transformer(text)
-        text_cls, text_encodings = text_encodings[:, 0], text_encodings[:, 1:]
-        text_embed = self.clip.to_text_latent(text_cls)
-        text_embed = l2norm(text_embed)
-
-        if not self.condition_on_text_encodings:            
-            return dict(text_embed = text_embed)
-
-        return dict(text_encodings = text_encodings, text_embed = text_embed, mask = text != 0)
+        # whether to force an l2norm, similar to clipping denoised, when sampling
+        self.sampling_clamp_l2norm = sampling_clamp_l2norm

    def p_mean_variance(self, x, t, text_cond, clip_denoised: bool):
        pred = self.net(x, t, **text_cond)
@@ -643,6 +781,9 @@ class DiffusionPrior(BaseGaussianDiffusion):
        if clip_denoised and not self.predict_x_start:
            x_recon.clamp_(-1., 1.)

+        if self.predict_x_start and self.sampling_clamp_l2norm:
+            x_recon = l2norm(x_recon)
+
        model_mean, posterior_variance, posterior_log_variance = self.q_posterior(x_start=x_recon, x_t=x, t=t)
        return model_mean, posterior_variance, posterior_log_variance

@@ -666,29 +807,21 @@ class DiffusionPrior(BaseGaussianDiffusion):
            img = self.p_sample(img, torch.full((b,), i, device = device, dtype = torch.long), text_cond = text_cond)
        return img

-    def p_losses(self, image_embed, t, text_cond, noise = None):
+    def p_losses(self, image_embed, times, text_cond, noise = None):
        noise = default(noise, lambda: torch.randn_like(image_embed))

-        image_embed_noisy = self.q_sample(x_start = image_embed, t = t, noise = noise)
+        image_embed_noisy = self.q_sample(x_start = image_embed, t = times, noise = noise)

-        x_recon = self.net(
+        pred = self.net(
            image_embed_noisy,
-            t,
+            times,
            cond_drop_prob = self.cond_drop_prob,
            **text_cond
        )

-        to_predict = noise if not self.predict_x_start else image_embed
-
-        if self.loss_type == 'l1':
-            loss = F.l1_loss(to_predict, x_recon)
-        elif self.loss_type == 'l2':
-            loss = F.mse_loss(to_predict, x_recon)
-        elif self.loss_type == "huber":
-            loss = F.smooth_l1_loss(to_predict, x_recon)
-        else:
-            raise NotImplementedError()
+        target = noise if not self.predict_x_start else image_embed

+        loss = self.loss_fn(pred, target)
        return loss

    @torch.no_grad()
@@ -701,7 +834,12 @@ class DiffusionPrior(BaseGaussianDiffusion):
        batch_size = text.shape[0]
        image_embed_dim = self.image_embed_dim

-        text_cond = self.get_text_cond(text)
+        text_embed, text_encodings, text_mask = self.clip.embed_text(text)
+
+        text_cond = dict(text_embed = text_embed)
+
+        if self.condition_on_text_encodings:
+            text_cond = {**text_cond, 'text_encodings': text_encodings, 'mask': text_mask}

        image_embeds = self.p_sample_loop((batch_size, image_embed_dim), text_cond = text_cond)
        text_embeds = text_cond['text_embed']
@@ -733,18 +871,18 @@ class DiffusionPrior(BaseGaussianDiffusion):
        assert not (self.condition_on_text_encodings and (not exists(text_encodings) and not exists(text))), 'text encodings must be present if you specified you wish to condition on it on initialization'

        if exists(image):
-            image_embed = self.get_image_embed(image)
+            image_embed, _ = self.clip.embed_image(image)

        # calculate text conditionings, based on what is passed in

        if exists(text):
-            text_cond = self.get_text_cond(text)
-        else:
-            text_cond = dict(
-                text_embed = text_embed,
-                text_encodings = text_encodings,
-                mask = text_mask
-            )
+            text_embed, text_encodings, text_mask = self.clip.embed_text(text)
+
+        text_cond = dict(text_embed = text_embed)
+
+        if self.condition_on_text_encodings:
+            assert exists(text_encodings), 'text encodings must be present for diffusion prior if specified'
+            text_cond = {**text_cond, 'text_encodings': text_encodings, 'mask': text_mask}

        # timestep conditioning from ddpm

@@ -753,8 +891,7 @@ class DiffusionPrior(BaseGaussianDiffusion):

        # calculate forward loss

-        loss = self.p_losses(image_embed, times, text_cond = text_cond, *args, **kwargs)
-        return loss
+        return self.p_losses(image_embed, times, text_cond = text_cond, *args, **kwargs)

 # decoder

@@ -785,6 +922,7 @@ class ConvNextBlock(nn.Module):
        dim_out,
        *,
        cond_dim = None,
+        time_cond_dim = None,
        mult = 2,
        norm = True
    ):
@@ -803,6 +941,14 @@ class ConvNextBlock(nn.Module):
                )
            )

+        self.time_mlp = None
+
+        if exists(time_cond_dim):
+            self.time_mlp = nn.Sequential(
+                nn.GELU(),
+                nn.Linear(time_cond_dim, dim)
+            )
+
        self.ds_conv = nn.Conv2d(dim, dim, 7, padding = 3, groups = dim)

        inner_dim = int(dim_out * mult)
@@ -815,9 +961,13 @@ class ConvNextBlock(nn.Module):

        self.res_conv = nn.Conv2d(dim, dim_out, 1) if need_projection else nn.Identity()

-    def forward(self, x, cond = None):
+    def forward(self, x, cond = None, time = None):
        h = self.ds_conv(x)

+        if exists(time) and exists(self.time_mlp):
+            t = self.time_mlp(time)
+            h = rearrange(t, 'b c -> b c 1 1') + h
+
        if exists(self.cross_attn):
            assert exists(cond)
            h = self.cross_attn(h, context = cond) + h
@@ -900,6 +1050,42 @@ class GridAttention(nn.Module):
        out = rearrange(out, '(b h w) (w1 w2) c -> b c (w1 h) (w2 w)', w1 = wsz, w2 = wsz, h = h // wsz, w = w // wsz)
        return out

+class LinearAttention(nn.Module):
+    def __init__(
+        self,
+        dim,
+        dim_head = 32,
+        heads = 8
+    ):
+        super().__init__()
+        self.scale = dim_head ** -0.5
+        self.heads = heads
+        inner_dim = dim_head * heads
+        self.norm = ChanLayerNorm(dim)
+
+        self.nonlin = nn.GELU()
+        self.to_qkv = nn.Conv2d(dim, inner_dim * 3, 1, bias = False)
+        self.to_out = nn.Conv2d(inner_dim, dim, 1, bias = False)
+
+    def forward(self, fmap):
+        h, x, y = self.heads, *fmap.shape[-2:]
+
+        fmap = self.norm(fmap)
+        q, k, v = self.to_qkv(fmap).chunk(3, dim = 1)
+        q, k, v = rearrange_many((q, k, v), 'b (h c) x y -> (b h) (x y) c', h = h)
+
+        q = q.softmax(dim = -1)
+        k = k.softmax(dim = -2)
+
+        q = q * self.scale
+
+        context = einsum('b n d, b n e -> b d e', k, v)
+        out = einsum('b n d, b d e -> b n e', q, context)
+        out = rearrange(out, '(b h) (x y) d -> b (h d) x y', h = h, x = x, y = y)
+
+        out = self.nonlin(out)
+        return self.to_out(out)
+
 class Unet(nn.Module):
    def __init__(
        self,
@@ -914,14 +1100,15 @@ class Unet(nn.Module):
        dim_mults=(1, 2, 4, 8),
        channels = 3,
        attn_dim_head = 32,
-        attn_heads = 8,
+        attn_heads = 16,
        lowres_cond = False, # for cascading diffusion - https://cascaded-diffusion.github.io/
        sparse_attn = False,
-        sparse_attn_window = 8,  # window size for sparse attention
        attend_at_middle = True, # whether to have a layer of attention at the bottleneck (can turn off for higher resolution in cascading DDPM, before bringing in efficient attention)
        cond_on_text_encodings = False,
        max_text_len = 256,
        cond_on_image_embeds = False,
+        init_dim = None,
+        init_conv_kernel_size = 7
    ):
        super().__init__()
        # save locals to take care of some hyperparameters for cascading DDPM
@@ -939,28 +1126,45 @@ class Unet(nn.Module):
        self.channels = channels

        init_channels = channels if not lowres_cond else channels * 2 # in cascading diffusion, one concats the low resolution image, blurred, for conditioning the higher resolution synthesis
+        init_dim = default(init_dim, dim // 2)

-        dims = [init_channels, *map(lambda m: dim * m, dim_mults)]
+        assert (init_conv_kernel_size % 2) == 1
+        self.init_conv = nn.Conv2d(init_channels, init_dim, init_conv_kernel_size, padding = init_conv_kernel_size // 2)
+
+        dims = [init_dim, *map(lambda m: dim * m, dim_mults)]
        in_out = list(zip(dims[:-1], dims[1:]))

        # time, image embeddings, and optional text encoding

        cond_dim = default(cond_dim, dim)
+        time_cond_dim = dim * 4

-        self.time_mlp = nn.Sequential(
+        self.to_time_hiddens = nn.Sequential(
            SinusoidalPosEmb(dim),
-            nn.Linear(dim, dim * 4),
-            nn.GELU(),
-            nn.Linear(dim * 4, cond_dim * num_time_tokens),
+            nn.Linear(dim, time_cond_dim),
+            nn.GELU()
+        )
+
+        self.to_time_tokens = nn.Sequential(
+            nn.Linear(time_cond_dim, cond_dim * num_time_tokens),
            Rearrange('b (r d) -> b r d', r = num_time_tokens)
        )

+        self.to_time_cond = nn.Sequential(
+            nn.Linear(time_cond_dim, time_cond_dim)
+        )
+
        self.image_to_cond = nn.Sequential(
            nn.Linear(image_embed_dim, cond_dim * num_image_tokens),
            Rearrange('b (n d) -> b n d', n = num_image_tokens)
        ) if image_embed_dim != cond_dim else nn.Identity()

-        self.text_to_cond = nn.LazyLinear(cond_dim) if not exists(text_embed_dim) else nn.Linear(text_embed_dim, cond_dim)
+        # text encoding conditioning (optional)
+
+        self.text_to_cond = None
+
+        if cond_on_text_encodings:
+            self.text_to_cond = nn.LazyLinear(cond_dim) if not exists(text_embed_dim) else nn.Linear(text_embed_dim, cond_dim)

        # finer control over whether to condition on image embeddings and text encodings
        # so one can have the latter unets in the cascading DDPMs only focus on super-resoluting
@@ -971,6 +1175,8 @@ class Unet(nn.Module):
        # for classifier free guidance

        self.null_image_embed = nn.Parameter(torch.randn(1, num_image_tokens, cond_dim))
+
+        self.max_text_len = max_text_len
        self.null_text_embed = nn.Parameter(torch.randn(1, max_text_len, cond_dim))

        # attention related params
@@ -989,26 +1195,26 @@ class Unet(nn.Module):
            layer_cond_dim = cond_dim if not is_first else None

            self.downs.append(nn.ModuleList([
-                ConvNextBlock(dim_in, dim_out, norm = ind != 0),
-                Residual(GridAttention(dim_out, window_size = sparse_attn_window, **attn_kwargs)) if sparse_attn else nn.Identity(),
-                ConvNextBlock(dim_out, dim_out, cond_dim = layer_cond_dim),
+                ConvNextBlock(dim_in, dim_out, time_cond_dim = time_cond_dim, norm = ind != 0),
+                Residual(LinearAttention(dim_out, **attn_kwargs)) if sparse_attn else nn.Identity(),
+                ConvNextBlock(dim_out, dim_out, cond_dim = layer_cond_dim, time_cond_dim = time_cond_dim),
                Downsample(dim_out) if not is_last else nn.Identity()
            ]))

        mid_dim = dims[-1]

-        self.mid_block1 = ConvNextBlock(mid_dim, mid_dim, cond_dim = cond_dim)
+        self.mid_block1 = ConvNextBlock(mid_dim, mid_dim, cond_dim = cond_dim, time_cond_dim = time_cond_dim)
        self.mid_attn = EinopsToAndFrom('b c h w', 'b (h w) c', Residual(Attention(mid_dim, **attn_kwargs))) if attend_at_middle else None
-        self.mid_block2 = ConvNextBlock(mid_dim, mid_dim, cond_dim = cond_dim)
+        self.mid_block2 = ConvNextBlock(mid_dim, mid_dim, cond_dim = cond_dim, time_cond_dim = time_cond_dim)

        for ind, (dim_in, dim_out) in enumerate(reversed(in_out[1:])):
            is_last = ind >= (num_resolutions - 2)
            layer_cond_dim = cond_dim if not is_last else None

            self.ups.append(nn.ModuleList([
-                ConvNextBlock(dim_out * 2, dim_in, cond_dim = layer_cond_dim),
-                Residual(GridAttention(dim_in, window_size = sparse_attn_window, **attn_kwargs)) if sparse_attn else nn.Identity(),
-                ConvNextBlock(dim_in, dim_in, cond_dim = layer_cond_dim),
+                ConvNextBlock(dim_out * 2, dim_in, cond_dim = layer_cond_dim, time_cond_dim = time_cond_dim),
+                Residual(LinearAttention(dim_in, **attn_kwargs)) if sparse_attn else nn.Identity(),
+                ConvNextBlock(dim_in, dim_in, cond_dim = layer_cond_dim, time_cond_dim = time_cond_dim),
                Upsample(dim_in)
            ]))

@@ -1024,13 +1230,14 @@ class Unet(nn.Module):
        self,
        *,
        lowres_cond,
-        channels
+        channels,
+        cond_on_image_embeds
    ):
-        if lowres_cond == self.lowres_cond and channels == self.channels:
+        if lowres_cond == self.lowres_cond and channels == self.channels and cond_on_image_embeds == self.cond_on_image_embeds:
            return self

-        updated_kwargs = {**self._locals, 'lowres_cond': lowres_cond, 'channels': channels}
-        return self.__class__(**updated_kwargs)
+        updated_kwargs = {'lowres_cond': lowres_cond, 'channels': channels, 'cond_on_image_embeds': cond_on_image_embeds}
+        return self.__class__(**{**self._locals, **updated_kwargs})

    def forward_with_cond_scale(
        self,
@@ -1043,7 +1250,7 @@ class Unet(nn.Module):
        if cond_scale == 1:
            return logits

-        null_logits = self.forward(*args, cond_drop_prob = 1., **kwargs)
+        null_logits = self.forward(*args, text_cond_drop_prob = 1., image_cond_drop_prob = 1., **kwargs)
        return null_logits + (logits - null_logits) * cond_scale

    def forward(
@@ -1054,7 +1261,9 @@ class Unet(nn.Module):
        image_embed,
        lowres_cond_img = None,
        text_encodings = None,
-        cond_drop_prob = 0.,
+        text_mask = None,
+        image_cond_drop_prob = 0.,
+        text_cond_drop_prob = 0.,
        blur_sigma = None,
        blur_kernel_size = None
    ):
@@ -1067,14 +1276,23 @@ class Unet(nn.Module):
        if exists(lowres_cond_img):
            x = torch.cat((x, lowres_cond_img), dim = 1)

+        # initial convolution
+
+        x = self.init_conv(x)
+
        # time conditioning

-        time_tokens = self.time_mlp(time)
+        time_hiddens = self.to_time_hiddens(time)
+
+        time_tokens = self.to_time_tokens(time_hiddens)
+        t = self.to_time_cond(time_hiddens)

        # conditional dropout

-        cond_prob_mask = prob_mask_like((batch_size,), cond_drop_prob, device = device)
-        cond_prob_mask = rearrange(cond_prob_mask, 'b -> b 1 1')
+        image_keep_mask = prob_mask_like((batch_size,), 1 - image_cond_drop_prob, device = device)
+        text_keep_mask = prob_mask_like((batch_size,), 1 - text_cond_drop_prob, device = device)
+
+        image_keep_mask, text_keep_mask = rearrange_many((image_keep_mask, text_keep_mask), 'b -> b 1 1')

        # mask out image embedding depending on condition dropout
        # for classifier free guidance
@@ -1085,7 +1303,7 @@ class Unet(nn.Module):
            image_tokens = self.image_to_cond(image_embed)

            image_tokens = torch.where(
-                cond_prob_mask,
+                image_keep_mask,
                image_tokens,
                self.null_image_embed
            )
@@ -1096,10 +1314,25 @@ class Unet(nn.Module):

        if exists(text_encodings) and self.cond_on_text_encodings:
            text_tokens = self.text_to_cond(text_encodings)
+            text_tokens = text_tokens[:, :self.max_text_len]
+
+            text_tokens_len = text_tokens.shape[1]
+            remainder = self.max_text_len - text_tokens_len
+
+            if remainder > 0:
+                text_tokens = F.pad(text_tokens, (0, 0, 0, remainder))
+
+            if exists(text_mask):
+                if remainder > 0:
+                    text_mask = F.pad(text_mask, (0, remainder), value = False)
+
+                text_mask = rearrange(text_mask, 'b n -> b n 1')
+                text_keep_mask = text_mask & text_keep_mask
+
            text_tokens = torch.where(
-                cond_prob_mask,
+                text_keep_mask,
                text_tokens,
-                self.null_text_embed[:, :text_tokens.shape[1]]
+                self.null_text_embed
            )

        # main conditioning tokens (c)
@@ -1119,24 +1352,24 @@ class Unet(nn.Module):
        hiddens = []

        for convnext, sparse_attn, convnext2, downsample in self.downs:
-            x = convnext(x, c)
+            x = convnext(x, c, t)
            x = sparse_attn(x)
-            x = convnext2(x, c)
+            x = convnext2(x, c, t)
            hiddens.append(x)
            x = downsample(x)

-        x = self.mid_block1(x, mid_c)
+        x = self.mid_block1(x, mid_c, t)

        if exists(self.mid_attn):
            x = self.mid_attn(x)

-        x = self.mid_block2(x, mid_c)
+        x = self.mid_block2(x, mid_c, t)

        for convnext, sparse_attn, convnext2, upsample in self.ups:
            x = torch.cat((x, hiddens.pop()), dim=1)
-            x = convnext(x, c)
+            x = convnext(x, c, t)
            x = sparse_attn(x)
-            x = convnext2(x, c)
+            x = convnext2(x, c, t)
            x = upsample(x)

        return self.final_conv(x)
@@ -1167,7 +1400,7 @@ class LowresConditioner(nn.Module):
        target_image_size = cast_tuple(target_image_size, 2)

        if self.training and self.downsample_first and exists(downsample_image_size):
-            cond_fmap = resize_image_to(cond_fmap, target_image_size, mode = self.cond_upsample_mode)
+            cond_fmap = resize_image_to(cond_fmap, downsample_image_size, mode = self.cond_upsample_mode)

        if self.training:
            # when training, blur the low resolution conditional image
@@ -1187,7 +1420,8 @@ class Decoder(BaseGaussianDiffusion):
        clip,
        vae = tuple(),
        timesteps = 1000,
-        cond_drop_prob = 0.2,
+        image_cond_drop_prob = 0.1,
+        text_cond_drop_prob = 0.5,
        loss_type = 'l1',
        beta_schedule = 'cosine',
        predict_x_start = False,
@@ -1198,6 +1432,8 @@ class Decoder(BaseGaussianDiffusion):
        blur_sigma = 0.1,                           # cascading ddpm - blur sigma
        blur_kernel_size = 3,                       # cascading ddpm - blur kernel size
        condition_on_text_encodings = False,        # the paper suggested that this didn't do much in the decoder, but i'm allowing the option for experimentation
+        clip_denoised = True,
+        clip_x_start = True
    ):
        super().__init__(
            beta_schedule = beta_schedule,
@@ -1205,8 +1441,12 @@ class Decoder(BaseGaussianDiffusion):
            loss_type = loss_type
        )

-        assert isinstance(clip, CLIP)
+        if isinstance(clip, CLIP):
+            clip = XClipAdapter(clip)
+
        freeze_model_and_make_eval_(clip)
+        assert isinstance(clip, BaseClipAdapter)
+
        self.clip = clip
        self.clip_image_size = clip.image_size
        self.channels = clip.image_channels
@@ -1233,6 +1473,7 @@ class Decoder(BaseGaussianDiffusion):

            one_unet = one_unet.cast_model_parameters(
                lowres_cond = not is_first,
+                cond_on_image_embeds = is_first,
                channels = unet_channels
            )

@@ -1266,7 +1507,13 @@ class Decoder(BaseGaussianDiffusion):

        # classifier free guidance

-        self.cond_drop_prob = cond_drop_prob
+        self.image_cond_drop_prob = image_cond_drop_prob
+        self.text_cond_drop_prob = text_cond_drop_prob
+
+        # whether to clip when sampling
+
+        self.clip_denoised = clip_denoised
+        self.clip_x_start = clip_x_start

    def get_unet(self, unet_number):
        assert 0 < unet_number <= len(self.unets)
@@ -1287,44 +1534,37 @@ class Decoder(BaseGaussianDiffusion):
        yield
        unet.cpu()

-    @torch.no_grad()
-    def get_text_encodings(self, text):
-        text_encodings = self.clip.text_transformer(text)
-        return text_encodings[:, 1:]

    @torch.no_grad()
    def get_image_embed(self, image):
-        image = resize_image_to(image, self.clip_image_size)
-        image_encoding = self.clip.visual_transformer(image)
-        image_cls = image_encoding[:, 0]
-        image_embed = self.clip.to_visual_latent(image_cls)
-        return l2norm(image_embed)
+        image_embed, _ = self.clip.embed_image(image)
+        return image_embed

-    def p_mean_variance(self, unet, x, t, image_embed, text_encodings = None, lowres_cond_img = None, clip_denoised = True, predict_x_start = False, cond_scale = 1.):
-        pred = unet.forward_with_cond_scale(x, t, image_embed = image_embed, text_encodings = text_encodings, cond_scale = cond_scale, lowres_cond_img = lowres_cond_img)
+    def p_mean_variance(self, unet, x, t, image_embed, text_encodings = None, text_mask = None, lowres_cond_img = None, clip_denoised = True, predict_x_start = False, cond_scale = 1.):
+        pred = unet.forward_with_cond_scale(x, t, image_embed = image_embed, text_encodings = text_encodings, text_mask = text_mask, cond_scale = cond_scale, lowres_cond_img = lowres_cond_img)

        if predict_x_start:
            x_recon = pred
        else:
            x_recon = self.predict_start_from_noise(x, t = t, noise = pred)

-        if clip_denoised and not predict_x_start:
+        if clip_denoised:
            x_recon.clamp_(-1., 1.)

        model_mean, posterior_variance, posterior_log_variance = self.q_posterior(x_start=x_recon, x_t=x, t=t)
        return model_mean, posterior_variance, posterior_log_variance

    @torch.no_grad()
-    def p_sample(self, unet, x, t, image_embed, text_encodings = None, cond_scale = 1., lowres_cond_img = None, predict_x_start = False, clip_denoised = True, repeat_noise = False):
+    def p_sample(self, unet, x, t, image_embed, text_encodings = None, text_mask = None, cond_scale = 1., lowres_cond_img = None, predict_x_start = False, clip_denoised = True, repeat_noise = False):
        b, *_, device = *x.shape, x.device
-        model_mean, _, model_log_variance = self.p_mean_variance(unet, x = x, t = t, image_embed = image_embed, text_encodings = text_encodings, cond_scale = cond_scale, lowres_cond_img = lowres_cond_img, clip_denoised = clip_denoised, predict_x_start = predict_x_start)
+        model_mean, _, model_log_variance = self.p_mean_variance(unet, x = x, t = t, image_embed = image_embed, text_encodings = text_encodings, text_mask = text_mask, cond_scale = cond_scale, lowres_cond_img = lowres_cond_img, clip_denoised = clip_denoised, predict_x_start = predict_x_start)
        noise = noise_like(x.shape, device, repeat_noise)
        # no noise when t == 0
        nonzero_mask = (1 - (t == 0).float()).reshape(b, *((1,) * (len(x.shape) - 1)))
        return model_mean + nonzero_mask * (0.5 * model_log_variance).exp() * noise

    @torch.no_grad()
-    def p_sample_loop(self, unet, shape, image_embed, predict_x_start = False, lowres_cond_img = None, text_encodings = None, cond_scale = 1):
+    def p_sample_loop(self, unet, shape, image_embed, predict_x_start = False, clip_denoised = True, lowres_cond_img = None, text_encodings = None, text_mask = None, cond_scale = 1):
        device = self.betas.device

        b = shape[0]
@@ -1337,59 +1577,68 @@ class Decoder(BaseGaussianDiffusion):
                torch.full((b,), i, device = device, dtype = torch.long),
                image_embed = image_embed,
                text_encodings = text_encodings,
+                text_mask = text_mask,
                cond_scale = cond_scale,
                lowres_cond_img = lowres_cond_img,
-                predict_x_start = predict_x_start
+                predict_x_start = predict_x_start,
+                clip_denoised = clip_denoised
            )

        return img

-    def p_losses(self, unet, x_start, t, *, image_embed, lowres_cond_img = None, text_encodings = None, predict_x_start = False, noise = None):
+    def p_losses(self, unet, x_start, times, *, image_embed, lowres_cond_img = None, text_encodings = None, text_mask = None, predict_x_start = False, noise = None):
        noise = default(noise, lambda: torch.randn_like(x_start))

-        x_noisy = self.q_sample(x_start = x_start, t = t, noise = noise)
+        x_noisy = self.q_sample(x_start = x_start, t = times, noise = noise)

-        x_recon = unet(
+        pred = unet(
            x_noisy,
-            t,
+            times,
            image_embed = image_embed,
            text_encodings = text_encodings,
+            text_mask = text_mask,
            lowres_cond_img = lowres_cond_img,
-            cond_drop_prob = self.cond_drop_prob
+            image_cond_drop_prob = self.image_cond_drop_prob,
+            text_cond_drop_prob = self.text_cond_drop_prob,
        )

        target = noise if not predict_x_start else x_start

-        if self.loss_type == 'l1':
-            loss = F.l1_loss(target, x_recon)
-        elif self.loss_type == 'l2':
-            loss = F.mse_loss(target, x_recon)
-        elif self.loss_type == "huber":
-            loss = F.smooth_l1_loss(target, x_recon)
-        else:
-            raise NotImplementedError()
-
+        loss = self.loss_fn(pred, target)
        return loss

    @torch.no_grad()
    @eval_decorator
-    def sample(self, image_embed, text = None, cond_scale = 1.):
+    def sample(
+        self,
+        image_embed,
+        text = None,
+        cond_scale = 1.,
+        stop_at_unet_number = None
+    ):
        batch_size = image_embed.shape[0]

-        text_encodings = self.get_text_encodings(text) if exists(text) else None
+        text_encodings = text_mask = None
+        if exists(text):
+            _, text_encodings, text_mask = self.clip.embed_text(text)

        assert not (self.condition_on_text_encodings and not exists(text_encodings)), 'text or text encodings must be passed into decoder if specified'
+        assert not (not self.condition_on_text_encodings and exists(text_encodings)), 'decoder specified not to be conditioned on text, yet it is presented'

        img = None

-        for unet, vae, channel, image_size, predict_x_start in tqdm(zip(self.unets, self.vaes, self.sample_channels, self.image_sizes, self.predict_x_start)):
-            with self.one_unet_in_gpu(unet = unet):
+        for unet_number, unet, vae, channel, image_size, predict_x_start in tqdm(zip(range(1, len(self.unets) + 1), self.unets, self.vaes, self.sample_channels, self.image_sizes, self.predict_x_start)):
+
+            context = self.one_unet_in_gpu(unet = unet) if image_embed.is_cuda else null_context()
+
+            with context:
                lowres_cond_img = None
                shape = (batch_size, channel, image_size, image_size)

                if unet.lowres_cond:
                    lowres_cond_img = self.to_lowres_cond(img, target_image_size = image_size)

+                is_latent_diffusion = isinstance(vae, VQGanVAE)
                image_size = vae.get_encoded_fmap_size(image_size)
                shape = (batch_size, vae.encoded_dim, image_size, image_size)

@@ -1401,13 +1650,18 @@ class Decoder(BaseGaussianDiffusion):
                    shape,
                    image_embed = image_embed,
                    text_encodings = text_encodings,
+                    text_mask = text_mask,
                    cond_scale = cond_scale,
                    predict_x_start = predict_x_start,
+                    clip_denoised = not is_latent_diffusion,
                    lowres_cond_img = lowres_cond_img
                )

                img = vae.decode(img)

+            if exists(stop_at_unet_number) and stop_at_unet_number == unet_number:
+                break
+
        return img

    def forward(
@@ -1436,11 +1690,14 @@ class Decoder(BaseGaussianDiffusion):
        times = torch.randint(0, self.num_timesteps, (b,), device = device, dtype = torch.long)

        if not exists(image_embed):
-            image_embed = self.get_image_embed(image)
+            image_embed, _ = self.clip.embed_image(image)

-        text_encodings = self.get_text_encodings(text) if exists(text) and not exists(text_encodings) else None
+        text_encodings = text_mask = None
+        if exists(text) and not exists(text_encodings):
+            _, text_encodings, text_mask = self.clip.embed_text(text)

        assert not (self.condition_on_text_encodings and not exists(text_encodings)), 'text or text encodings must be passed into decoder if specified'
+        assert not (not self.condition_on_text_encodings and exists(text_encodings)), 'decoder specified not to be conditioned on text, yet it is presented'

        lowres_cond_img = self.to_lowres_cond(image, target_image_size = target_image_size, downsample_image_size = self.image_sizes[unet_index - 1]) if unet_number > 1 else None
        image = resize_image_to(image, target_image_size)
@@ -1452,7 +1709,7 @@ class Decoder(BaseGaussianDiffusion):
            if exists(lowres_cond_img):
                lowres_cond_img = vae.encode(lowres_cond_img)

-        return self.p_losses(unet, image, times, image_embed = image_embed, text_encodings = text_encodings, lowres_cond_img = lowres_cond_img, predict_x_start = predict_x_start)
+        return self.p_losses(unet, image, times, image_embed = image_embed, text_encodings = text_encodings, text_mask = text_mask, lowres_cond_img = lowres_cond_img, predict_x_start = predict_x_start)

 # main class

@@ -1473,12 +1730,15 @@ class DALLE2(nn.Module):
        self.prior_num_samples = prior_num_samples
        self.decoder_need_text_cond = self.decoder.condition_on_text_encodings

+        self.to_pil = T.ToPILImage()
+
    @torch.no_grad()
    @eval_decorator
    def forward(
        self,
        text,
-        cond_scale = 1.
+        cond_scale = 1.,
+        return_pil_images = False
    ):
        device = next(self.parameters()).device
        one_text = isinstance(text, str) or (not is_list_str(text) and text.shape[0] == 1)
@@ -1492,6 +1752,9 @@ class DALLE2(nn.Module):
        text_cond = text if self.decoder_need_text_cond else None
        images = self.decoder.sample(image_embed, text = text_cond, cond_scale = cond_scale)

+        if return_pil_images:
+            images = list(map(self.to_pil, images.unbind(dim = 0)))
+
        if one_text:
            return images[0]

--- a/dalle2_pytorch/optimizer.py
+++ b/dalle2_pytorch/optimizer.py
@@ -0,0 +1,29 @@
+from torch.optim import AdamW, Adam
+
+def separate_weight_decayable_params(params):
+    no_wd_params = set([param for param in params if param.ndim < 2])
+    wd_params = set(params) - no_wd_params
+    return wd_params, no_wd_params
+
+def get_optimizer(
+    params,
+    lr = 3e-4,
+    wd = 1e-2,
+    betas = (0.9, 0.999),
+    filter_by_requires_grad = False
+):
+    if filter_by_requires_grad:
+        params = list(filter(lambda t: t.requires_grad, params))
+
+    if wd == 0:
+        return Adam(params, lr = lr, betas = betas)
+
+    params = set(params)
+    wd_params, no_wd_params = separate_weight_decayable_params(params)
+
+    param_groups = [
+        {'params': list(wd_params)},
+        {'params': list(no_wd_params), 'weight_decay': 0},
+    ]
+
+    return AdamW(param_groups, lr = lr, weight_decay = wd, betas = betas)
--- a/dalle2_pytorch/train.py
+++ b/dalle2_pytorch/train.py
@@ -1,6 +1,43 @@
 import copy
+from functools import partial
+
 import torch
 from torch import nn
+from torch.cuda.amp import autocast, GradScaler
+
+from dalle2_pytorch.dalle2_pytorch import Decoder
+from dalle2_pytorch.optimizer import get_optimizer
+
+# helper functions
+
+def exists(val):
+    return val is not None
+
+def cast_tuple(val, length = 1):
+    return val if isinstance(val, tuple) else ((val,) * length)
+
+def pick_and_pop(keys, d):
+    values = list(map(lambda key: d.pop(key), keys))
+    return dict(zip(keys, values))
+
+def group_dict_by_key(cond, d):
+    return_val = [dict(),dict()]
+    for key in d.keys():
+        match = bool(cond(key))
+        ind = int(not match)
+        return_val[ind][key] = d[key]
+    return (*return_val,)
+
+def string_begins_with(prefix, str):
+    return str.startswith(prefix)
+
+def group_by_key_prefix(prefix, d):
+    return group_dict_by_key(partial(string_begins_with, prefix), d)
+
+def groupby_prefix_and_trim(prefix, d):
+    kwargs_with_prefix, kwargs = group_dict_by_key(partial(string_begins_with, prefix), d)
+    kwargs_without_prefix = dict(map(lambda x: (x[0][len(prefix):], x[1]), tuple(kwargs_with_prefix.items())))
+    return kwargs_without_prefix, kwargs

 # exponential moving average wrapper

@@ -9,16 +46,16 @@ class EMA(nn.Module):
        self,
        model,
        beta = 0.99,
-        ema_update_after_step = 1000,
-        ema_update_every = 10,
+        update_after_step = 1000,
+        update_every = 10,
    ):
        super().__init__()
        self.beta = beta
        self.online_model = model
        self.ema_model = copy.deepcopy(model)

-        self.ema_update_after_step = ema_update_after_step # only start EMA after this step number, starting at 0
-        self.ema_update_every = ema_update_every
+        self.update_after_step = update_after_step # only start EMA after this step number, starting at 0
+        self.update_every = update_every

        self.register_buffer('initted', torch.Tensor([False]))
        self.register_buffer('step', torch.tensor([0.]))
@@ -26,7 +63,7 @@ class EMA(nn.Module):
    def update(self):
        self.step += 1

-        if self.step <= self.ema_update_after_step or (self.step % self.ema_update_every) != 0:
+        if self.step <= self.update_after_step or (self.step % self.update_every) != 0:
            return

        if not self.initted:
@@ -35,7 +72,7 @@ class EMA(nn.Module):

        self.update_moving_average(self.ema_model, self.online_model)

-    def update_moving_average(ma_model, current_model):
+    def update_moving_average(self, ma_model, current_model):
        def calculate_ema(beta, old, new):
            if not exists(old):
                return new
@@ -51,3 +88,111 @@ class EMA(nn.Module):

    def __call__(self, *args, **kwargs):
        return self.ema_model(*args, **kwargs)
+
+# trainers
+
+class DecoderTrainer(nn.Module):
+    def __init__(
+        self,
+        decoder,
+        use_ema = True,
+        lr = 3e-4,
+        wd = 1e-2,
+        max_grad_norm = None,
+        amp = False,
+        **kwargs
+    ):
+        super().__init__()
+        assert isinstance(decoder, Decoder)
+        ema_kwargs, kwargs = groupby_prefix_and_trim('ema_', kwargs)
+
+        self.decoder = decoder
+        self.num_unets = len(self.decoder.unets)
+
+        self.use_ema = use_ema
+
+        if use_ema:
+            has_lazy_linear = any([type(module) == nn.LazyLinear for module in decoder.modules()])
+            assert not has_lazy_linear, 'you must set the text_embed_dim on your u-nets if you plan on doing automatic exponential moving average'
+
+        self.ema_unets = nn.ModuleList([])
+
+        self.amp = amp
+
+        # be able to finely customize learning rate, weight decay
+        # per unet
+
+        lr, wd = map(partial(cast_tuple, length = self.num_unets), (lr, wd))
+
+        for ind, (unet, unet_lr, unet_wd) in enumerate(zip(self.decoder.unets, lr, wd)):
+            optimizer = get_optimizer(
+                unet.parameters(),
+                lr = unet_lr,
+                wd = unet_wd,
+                **kwargs
+            )
+
+            setattr(self, f'optim{ind}', optimizer) # cannot use pytorch ModuleList for some reason with optimizers
+
+            if self.use_ema:
+                self.ema_unets.append(EMA(unet, **ema_kwargs))
+
+            scaler = GradScaler(enabled = amp)
+            setattr(self, f'scaler{ind}', scaler)
+
+        # gradient clipping if needed
+
+        self.max_grad_norm = max_grad_norm
+
+    @property
+    def unets(self):
+        return nn.ModuleList([ema.ema_model for ema in self.ema_unets])
+
+    def scale(self, loss, *, unet_number):
+        assert 1 <= unet_number <= self.num_unets
+        index = unet_number - 1
+        scaler = getattr(self, f'scaler{index}')
+        return scaler.scale(loss)
+
+    def update(self, unet_number):
+        assert 1 <= unet_number <= self.num_unets
+        index = unet_number - 1
+        unet = self.decoder.unets[index]
+
+        if exists(self.max_grad_norm):
+            nn.utils.clip_grad_norm_(unet.parameters(), self.max_grad_norm)
+
+        optimizer = getattr(self, f'optim{index}')
+        scaler = getattr(self, f'scaler{index}')
+
+        scaler.step(optimizer)
+        scaler.update()
+        optimizer.zero_grad()
+
+        if self.use_ema:
+            ema_unet = self.ema_unets[index]
+            ema_unet.update()
+
+    @torch.no_grad()
+    def sample(self, *args, **kwargs):
+        if self.use_ema:
+            trainable_unets = self.decoder.unets
+            self.decoder.unets = self.unets                  # swap in exponential moving averaged unets for sampling
+
+        output = self.decoder.sample(*args, **kwargs)
+
+        if self.use_ema:
+            self.decoder.unets = trainable_unets             # restore original training unets
+        return output
+
+    def forward(
+        self,
+        x,
+        *,
+        unet_number,
+        divisor = 1,
+        **kwargs
+    ):
+        with autocast(enabled = self.amp):
+            loss = self.decoder(x, unet_number = unet_number, **kwargs)
+        return self.scale(loss / divisor, unet_number = unet_number)
--- a/dalle2_pytorch/train_vqgan_vae.py
+++ b/dalle2_pytorch/train_vqgan_vae.py
@@ -0,0 +1,266 @@
+from math import sqrt
+import copy
+from random import choice
+from pathlib import Path
+from shutil import rmtree
+
+import torch
+from torch import nn
+
+from PIL import Image
+from torchvision.datasets import ImageFolder
+import torchvision.transforms as T
+from torch.utils.data import Dataset, DataLoader, random_split
+from torchvision.utils import make_grid, save_image
+
+from einops import rearrange
+
+from dalle2_pytorch.train import EMA
+from dalle2_pytorch.vqgan_vae import VQGanVAE
+from dalle2_pytorch.optimizer import get_optimizer
+
+# helpers
+
+def exists(val):
+    return val is not None
+
+def noop(*args, **kwargs):
+    pass
+
+def cycle(dl):
+    while True:
+        for data in dl:
+            yield data
+
+def cast_tuple(t):
+    return t if isinstance(t, (tuple, list)) else (t,)
+
+def yes_or_no(question):
+    answer = input(f'{question} (y/n) ')
+    return answer.lower() in ('yes', 'y')
+
+def accum_log(log, new_logs):
+    for key, new_value in new_logs.items():
+        old_value = log.get(key, 0.)
+        log[key] = old_value + new_value
+    return log
+
+# classes
+
+class ImageDataset(Dataset):
+    def __init__(
+        self,
+        folder,
+        image_size,
+        exts = ['jpg', 'jpeg', 'png']
+    ):
+        super().__init__()
+        self.folder = folder
+        self.image_size = image_size
+        self.paths = [p for ext in exts for p in Path(f'{folder}').glob(f'**/*.{ext}')]
+
+        print(f'{len(self.paths)} training samples found at {folder}')
+
+        self.transform = T.Compose([
+            T.Lambda(lambda img: img.convert('RGB') if img.mode != 'RGB' else img),
+            T.Resize(image_size),
+            T.RandomHorizontalFlip(),
+            T.CenterCrop(image_size),
+            T.ToTensor()
+        ])
+
+    def __len__(self):
+        return len(self.paths)
+
+    def __getitem__(self, index):
+        path = self.paths[index]
+        img = Image.open(path)
+        return self.transform(img)
+
+# main trainer class
+
+class VQGanVAETrainer(nn.Module):
+    def __init__(
+        self,
+        vae,
+        *,
+        num_train_steps,
+        lr,
+        batch_size,
+        folder,
+        grad_accum_every,
+        wd = 0.,
+        save_results_every = 100,
+        save_model_every = 1000,
+        results_folder = './results',
+        valid_frac = 0.05,
+        random_split_seed = 42,
+        ema_beta = 0.995,
+        ema_update_after_step = 2000,
+        ema_update_every = 10,
+        apply_grad_penalty_every = 4,
+    ):
+        super().__init__()
+        assert isinstance(vae, VQGanVAE), 'vae must be instance of VQGanVAE'
+        image_size = vae.image_size
+
+        self.vae = vae
+        self.ema_vae = EMA(vae, update_after_step = ema_update_after_step, update_every = ema_update_every)
+
+        self.register_buffer('steps', torch.Tensor([0]))
+
+        self.num_train_steps = num_train_steps
+        self.batch_size = batch_size
+        self.grad_accum_every = grad_accum_every
+
+        all_parameters = set(vae.parameters())
+        discr_parameters = set(vae.discr.parameters())
+        vae_parameters = all_parameters - discr_parameters
+
+        self.optim = get_optimizer(vae_parameters, lr = lr, wd = wd)
+        self.discr_optim = get_optimizer(discr_parameters, lr = lr, wd = wd)
+
+        # create dataset
+
+        self.ds = ImageDataset(folder, image_size = image_size)
+
+        # split for validation
+
+        if valid_frac > 0:
+            train_size = int((1 - valid_frac) * len(self.ds))
+            valid_size = len(self.ds) - train_size
+            self.ds, self.valid_ds = random_split(self.ds, [train_size, valid_size], generator = torch.Generator().manual_seed(random_split_seed))
+            print(f'training with dataset of {len(self.ds)} samples and validating with randomly splitted {len(self.valid_ds)} samples')
+        else:
+            self.valid_ds = self.ds
+            print(f'training with shared training and valid dataset of {len(self.ds)} samples')
+
+        # dataloader
+
+        self.dl = cycle(DataLoader(
+            self.ds,
+            batch_size = batch_size,
+            shuffle = True
+        ))
+
+        self.valid_dl = cycle(DataLoader(
+            self.valid_ds,
+            batch_size = batch_size,
+            shuffle = True
+        ))
+
+        self.save_model_every = save_model_every
+        self.save_results_every = save_results_every
+
+        self.apply_grad_penalty_every = apply_grad_penalty_every
+
+        self.results_folder = Path(results_folder)
+
+        if len([*self.results_folder.glob('**/*')]) > 0 and yes_or_no('do you want to clear previous experiment checkpoints and results?'):
+            rmtree(str(self.results_folder))
+
+        self.results_folder.mkdir(parents = True, exist_ok = True)
+
+    def train_step(self):
+        device = next(self.vae.parameters()).device
+        steps = int(self.steps.item())
+        apply_grad_penalty = not (steps % self.apply_grad_penalty_every)
+
+        self.vae.train()
+
+        # logs
+
+        logs = {}
+
+        # update vae (generator)
+
+        for _ in range(self.grad_accum_every):
+            img = next(self.dl)
+            img = img.to(device)
+
+            loss = self.vae(
+                img,
+                return_loss = True,
+                apply_grad_penalty = apply_grad_penalty
+            )
+
+            accum_log(logs, {'loss': loss.item() / self.grad_accum_every})
+
+            (loss / self.grad_accum_every).backward()
+
+        self.optim.step()
+        self.optim.zero_grad()
+
+
+        # update discriminator
+
+        if exists(self.vae.discr):
+            discr_loss = 0
+            for _ in range(self.grad_accum_every):
+                img = next(self.dl)
+                img = img.to(device)
+
+                loss = self.vae(img, return_discr_loss = True)
+                accum_log(logs, {'discr_loss': loss.item() / self.grad_accum_every})
+
+                (loss / self.grad_accum_every).backward()
+
+            self.discr_optim.step()
+            self.discr_optim.zero_grad()
+
+            # log
+
+            print(f"{steps}: vae loss: {logs['loss']} - discr loss: {logs['discr_loss']}")
+
+        # update exponential moving averaged generator
+
+        self.ema_vae.update()
+
+        # sample results every so often
+
+        if not (steps % self.save_results_every):
+            for model, filename in ((self.ema_vae.ema_model, f'{steps}.ema'), (self.vae, str(steps))):
+                model.eval()
+
+                imgs = next(self.dl)
+                imgs = imgs.to(device)
+
+                recons = model(imgs)
+                nrows = int(sqrt(self.batch_size))
+
+                imgs_and_recons = torch.stack((imgs, recons), dim = 0)
+                imgs_and_recons = rearrange(imgs_and_recons, 'r b ... -> (b r) ...')
+
+                imgs_and_recons = imgs_and_recons.detach().cpu().float().clamp(0., 1.)
+                grid = make_grid(imgs_and_recons, nrow = 2, normalize = True, value_range = (0, 1))
+
+                logs['reconstructions'] = grid
+
+                save_image(grid, str(self.results_folder / f'{filename}.png'))
+
+            print(f'{steps}: saving to {str(self.results_folder)}')
+
+        # save model every so often
+
+        if not (steps % self.save_model_every):
+            state_dict = self.vae.state_dict()
+            model_path = str(self.results_folder / f'vae.{steps}.pt')
+            torch.save(state_dict, model_path)
+
+            ema_state_dict = self.ema_vae.state_dict()
+            model_path = str(self.results_folder / f'vae.{steps}.ema.pt')
+            torch.save(ema_state_dict, model_path)
+
+            print(f'{steps}: saving model to {str(self.results_folder)}')
+
+        self.steps += 1
+        return logs
+
+    def train(self, log_fn = noop):
+        device = next(self.vae.parameters()).device
+
+        while self.steps < self.num_train_steps:
+            logs = self.train_step()
+            log_fn(logs)
+
+        print('training complete')
--- a/dalle2_pytorch/vqgan_vae.py
+++ b/dalle2_pytorch/vqgan_vae.py
@@ -15,8 +15,6 @@ from einops import rearrange, reduce, repeat
 from einops_exts import rearrange_many
 from einops.layers.torch import Rearrange

-from dalle2_pytorch.attention import QueryAttnUpsample
-
 # constants

 MList = nn.ModuleList
@@ -329,6 +327,108 @@ class ResBlock(nn.Module):
    def forward(self, x):
        return self.net(x) + x

+# convnext enc dec
+
+class ChanLayerNorm(nn.Module):
+    def __init__(self, dim, eps = 1e-5):
+        super().__init__()
+        self.eps = eps
+        self.g = nn.Parameter(torch.ones(1, dim, 1, 1))
+
+    def forward(self, x):
+        var = torch.var(x, dim = 1, unbiased = False, keepdim = True)
+        mean = torch.mean(x, dim = 1, keepdim = True)
+        return (x - mean) / (var + self.eps).sqrt() * self.g
+
+class ConvNext(nn.Module):
+    def __init__(self, dim, mult = 4, kernel_size = 3, ds_kernel_size = 7):
+        super().__init__()
+        inner_dim = int(dim * mult)
+        self.net = nn.Sequential(
+            nn.Conv2d(dim, dim, ds_kernel_size, padding = ds_kernel_size // 2, groups = dim),
+            ChanLayerNorm(dim),
+            nn.Conv2d(dim, inner_dim, kernel_size, padding = kernel_size // 2),
+            nn.GELU(),
+            nn.Conv2d(inner_dim, dim, kernel_size, padding = kernel_size // 2)
+        )
+
+    def forward(self, x):
+        return self.net(x) + x
+
+class ConvNextEncDec(nn.Module):
+    def __init__(
+        self,
+        dim,
+        *,
+        channels = 3,
+        layers = 4,
+        layer_mults = None,
+        num_blocks = 1,
+        first_conv_kernel_size = 5,
+        use_attn = True,
+        attn_dim_head = 64,
+        attn_heads = 8,
+        attn_dropout = 0.,
+    ):
+        super().__init__()
+
+        self.layers = layers
+
+        self.encoders = MList([])
+        self.decoders = MList([])
+
+        layer_mults = default(layer_mults, list(map(lambda t: 2 ** t, range(layers))))
+        assert len(layer_mults) == layers, 'layer multipliers must be equal to designated number of layers'
+
+        layer_dims = [dim * mult for mult in layer_mults]
+        dims = (dim, *layer_dims)
+
+        self.encoded_dim = dims[-1]
+
+        dim_pairs = zip(dims[:-1], dims[1:])
+
+        append = lambda arr, t: arr.append(t)
+        prepend = lambda arr, t: arr.insert(0, t)
+
+        if not isinstance(num_blocks, tuple):
+            num_blocks = (*((0,) * (layers - 1)), num_blocks)
+
+        if not isinstance(use_attn, tuple):
+            use_attn = (*((False,) * (layers - 1)), use_attn)
+
+        assert len(num_blocks) == layers, 'number of blocks config must be equal to number of layers'
+        assert len(use_attn) == layers
+
+        for layer_index, (dim_in, dim_out), layer_num_blocks, layer_use_attn in zip(range(layers), dim_pairs, num_blocks, use_attn):
+            append(self.encoders, nn.Sequential(nn.Conv2d(dim_in, dim_out, 4, stride = 2, padding = 1), leaky_relu()))
+            prepend(self.decoders, nn.Sequential(nn.ConvTranspose2d(dim_out, dim_in, 4, 2, 1), leaky_relu()))
+
+            if layer_use_attn:
+                prepend(self.decoders, VQGanAttention(dim = dim_out, heads = attn_heads, dim_head = attn_dim_head, dropout = attn_dropout))
+
+            for _ in range(layer_num_blocks):
+                append(self.encoders, ConvNext(dim_out))
+                prepend(self.decoders, ConvNext(dim_out))
+
+            if layer_use_attn:
+                append(self.encoders, VQGanAttention(dim = dim_out, heads = attn_heads, dim_head = attn_dim_head, dropout = attn_dropout))
+
+        prepend(self.encoders, nn.Conv2d(channels, dim, first_conv_kernel_size, padding = first_conv_kernel_size // 2))
+        append(self.decoders, nn.Conv2d(dim, channels, 1))
+
+    def get_encoded_fmap_size(self, image_size):
+        return image_size // (2 ** self.layers)
+
+    def encode(self, x):
+        for enc in self.encoders:
+            x = enc(x)
+        return x
+
+    def decode(self, x):
+        for dec in self.decoders:
+            x = dec(x)
+        return x
+
 # vqgan attention layer

 class VQGanAttention(nn.Module):
@@ -547,6 +647,7 @@ class VQGanVAE(nn.Module):
        l2_recon_loss = False,
        use_hinge_loss = True,
        vgg = None,
+        vq_codebook_dim = 256,
        vq_codebook_size = 512,
        vq_decay = 0.8,
        vq_commitment_weight = 1.,
@@ -569,6 +670,8 @@ class VQGanVAE(nn.Module):
            enc_dec_klass = ResnetEncDec
        elif vae_type == 'vit':
            enc_dec_klass = ViTEncDec
+        elif vae_type == 'convnext':
+            enc_dec_klass = ConvNextEncDec
        else:
            raise ValueError(f'{vae_type} not valid')

@@ -581,6 +684,7 @@ class VQGanVAE(nn.Module):

        self.vq = VQ(
            dim = self.enc_dec.encoded_dim,
+            codebook_dim = vq_codebook_dim,
            codebook_size = vq_codebook_size,
            decay = vq_decay,
            commitment_weight = vq_commitment_weight,
--- a/setup.py
+++ b/setup.py
@@ -10,7 +10,7 @@ setup(
      'dream = dalle2_pytorch.cli:dream'
    ],
  },
-  version = '0.0.54',
+  version = '0.0.88',
  license='MIT',
  description = 'DALL-E 2',
  author = 'Phil Wang',
@@ -23,15 +23,18 @@ setup(
  ],
  install_requires=[
    'click',
+    'clip-anytorch',
    'einops>=0.4',
    'einops-exts>=0.0.3',
+    'embedding-reader',
    'kornia>=0.5.4',
    'pillow',
    'torch>=1.10',
    'torchvision',
    'tqdm',
    'vector-quantize-pytorch',
-    'x-clip>=0.4.4',
+    'webdataset',
+    'x-clip>=0.5.1',
    'youtokentome'
  ],
  classifiers=[
--- a/train_diffusion_prior.py
+++ b/train_diffusion_prior.py
@@ -0,0 +1,212 @@
+import os
+import math
+import argparse
+
+import torch
+from torch import nn
+from embedding_reader import EmbeddingReader
+from dalle2_pytorch import DiffusionPrior, DiffusionPriorNetwork
+from dalle2_pytorch.optimizer import get_optimizer
+
+import time
+from tqdm import tqdm
+
+import wandb
+os.environ["WANDB_SILENT"] = "true"
+
+def eval_model(model,device,image_reader,text_reader,start,end,batch_size,loss_type,phase="Validation"):
+    model.eval()
+    with torch.no_grad():
+        for emb_images,emb_text in zip(image_reader(batch_size=batch_size, start=start, end=end),
+                text_reader(batch_size=batch_size, start=start, end=end)):
+            emb_images_tensor = torch.tensor(emb_images[0]).to(device)
+            emb_text_tensor = torch.tensor(emb_text[0]).to(device)
+            loss = model(text_embed = emb_text_tensor, image_embed = emb_images_tensor)
+
+            # Log to wandb
+            wandb.log({f'{phase} {loss_type}': loss})
+
+def save_model(save_path,state_dict):
+    # Saving State Dict
+    print("====================================== Saving checkpoint ======================================")
+    torch.save(state_dict, save_path+'/'+str(time.time())+'_saved_model.pth')
+
+def train(image_embed_dim,
+          image_embed_url,
+          text_embed_url,
+          batch_size,
+          train_percent,
+          val_percent,
+          test_percent,
+          num_epochs,
+          dp_loss_type,
+          clip,
+          dp_condition_on_text_encodings,
+          dp_timesteps,
+          dp_cond_drop_prob,
+          dpn_depth,
+          dpn_dim_head,
+          dpn_heads,
+          save_interval,
+          save_path,
+          device,
+          learning_rate=0.001,
+          max_grad_norm=0.5,
+          weight_decay=0.01):
+
+    # DiffusionPriorNetwork 
+    prior_network = DiffusionPriorNetwork( 
+            dim = image_embed_dim, 
+            depth = dpn_depth, 
+            dim_head = dpn_dim_head, 
+            heads = dpn_heads).to(device)
+    
+    # DiffusionPrior with text embeddings and image embeddings pre-computed
+    diffusion_prior = DiffusionPrior( 
+            net = prior_network, 
+            clip = clip, 
+            image_embed_dim = image_embed_dim, 
+            timesteps = dp_timesteps,
+            cond_drop_prob = dp_cond_drop_prob, 
+            loss_type = dp_loss_type, 
+            condition_on_text_encodings = dp_condition_on_text_encodings).to(device)
+
+    # Get image and text embeddings from the servers
+    print("==============Downloading embeddings - image and text====================")
+    image_reader = EmbeddingReader(embeddings_folder=image_embed_url, file_format="npy")
+    text_reader  = EmbeddingReader(embeddings_folder=text_embed_url, file_format="npy")
+    num_data_points = text_reader.count
+
+    # Create save_path if it doesn't exist
+    if not os.path.exists(save_path):
+        os.makedirs(save_path)
+
+    ### Training code ###
+    optimizer = get_optimizer(diffusion_prior.net.parameters(), wd=weight_decay, lr=learning_rate)
+    epochs = num_epochs
+
+    step = 0
+    t = time.time()
+
+    train_set_size = int(train_percent*num_data_points)
+    val_set_size = int(val_percent*num_data_points)
+
+    for _ in range(epochs):
+        diffusion_prior.train()
+
+        for emb_images,emb_text in zip(image_reader(batch_size=batch_size, start=0, end=train_set_size),
+                text_reader(batch_size=batch_size, start=0, end=train_set_size)):
+            emb_images_tensor = torch.tensor(emb_images[0]).to(device)
+            emb_text_tensor = torch.tensor(emb_text[0]).to(device)
+            optimizer.zero_grad()
+            loss = diffusion_prior(text_embed = emb_text_tensor,image_embed = emb_images_tensor)
+            loss.backward()
+            # Samples per second
+            step+=1
+            samples_per_sec = batch_size*step/(time.time()-t)
+            # Save checkpoint every save_interval minutes
+            if(int(time.time()-t) >= 60*save_interval):
+                t = time.time()
+                save_model(save_path,diffusion_prior.state_dict())
+            # Log to wandb
+            wandb.log({"Training loss": loss.item(),
+                        "Steps": step,
+                        "Samples per second": samples_per_sec})
+
+            nn.init.clip_grad_norm_(diffusion_prior.parameters(), max_grad_norm)
+            optimizer.step()
+
+        ### Evaluate model(validation run) ###
+        start = train_set_size
+        end=start+val_set_size
+        eval_model(diffusion_prior,device,image_reader,text_reader,start,end,batch_size,dp_loss_type,phase="Validation")
+
+    ### Test run ###
+    test_set_size = int(test_percent*train_set_size) 
+    start=train_set_size+val_set_size
+    end=num_data_points
+    eval_model(diffusion_prior,device,image_reader,text_reader,start,end,batch_size,dp_loss_type,phase="Test")
+
+def main():
+    parser = argparse.ArgumentParser()
+    # Logging
+    parser.add_argument("--wandb-entity", type=str, default="laion")
+    parser.add_argument("--wandb-project", type=str, default="diffusion-prior")
+    parser.add_argument("--wandb-name", type=str, default="laion-dprior")
+    parser.add_argument("--wandb-dataset", type=str, default="LAION-5B")
+    parser.add_argument("--wandb-arch", type=str, default="DiffusionPrior")
+    # URLs for embeddings 
+    parser.add_argument("--image-embed-url", type=str, default="https://mystic.the-eye.eu/public/AI/cah/laion5b/embeddings/laion2B-en/img_emb/")
+    parser.add_argument("--text-embed-url", type=str, default="https://mystic.the-eye.eu/public/AI/cah/laion5b/embeddings/laion2B-en/text_emb/")
+    # Hyperparameters
+    parser.add_argument("--learning-rate", type=float, default=0.001)
+    parser.add_argument("--weight-decay", type=float, default=0.01)
+    parser.add_argument("--max-grad-norm", type=float, default=0.5)
+    parser.add_argument("--batch-size", type=int, default=10**4)
+    parser.add_argument("--num-epochs", type=int, default=5)
+    # Image embed dimension
+    parser.add_argument("--image-embed-dim", type=int, default=768)
+    # Train-test split
+    parser.add_argument("--train-percent", type=float, default=0.7)
+    parser.add_argument("--val-percent", type=float, default=0.2)
+    parser.add_argument("--test-percent", type=float, default=0.1)
+    # LAION training(pre-computed embeddings)
+    # DiffusionPriorNetwork(dpn) parameters
+    parser.add_argument("--dpn-depth", type=int, default=6)
+    parser.add_argument("--dpn-dim-head", type=int, default=64)
+    parser.add_argument("--dpn-heads", type=int, default=8)
+    # DiffusionPrior(dp) parameters
+    parser.add_argument("--dp-condition-on-text-encodings", type=bool, default=False)
+    parser.add_argument("--dp-timesteps", type=int, default=100)
+    parser.add_argument("--dp-cond-drop-prob", type=float, default=0.2)
+    parser.add_argument("--dp-loss-type", type=str, default="l2")
+    parser.add_argument("--clip", type=str, default=None)
+    # Model checkpointing interval(minutes)
+    parser.add_argument("--save-interval", type=int, default=30)
+    parser.add_argument("--save-path", type=str, default="./diffusion_prior_checkpoints")
+
+    args = parser.parse_args()
+    print("Setting up wandb logging... Please wait...")
+    wandb.init(
+      entity=args.wandb_entity,
+      project=args.wandb_project,
+      config={
+      "learning_rate": args.learning_rate,
+      "architecture": args.wandb_arch,
+      "dataset": args.wandb_dataset,
+      "epochs": args.num_epochs,
+      })
+    print("wandb logging setup done!")
+    # Obtain the utilized device.
+
+    has_cuda = torch.cuda.is_available()
+    if has_cuda:
+        device = torch.device("cuda:0")
+        torch.cuda.set_device(device)
+
+    # Training loop
+    train(args.image_embed_dim,
+          args.image_embed_url,
+          args.text_embed_url,
+          args.batch_size,
+          args.train_percent,
+          args.val_percent,
+          args.test_percent,
+          args.num_epochs,
+          args.dp_loss_type,
+          args.clip,
+          args.dp_condition_on_text_encodings,
+          args.dp_timesteps,
+          args.dp_cond_drop_prob,
+          args.dpn_depth,
+          args.dpn_dim_head,
+          args.dpn_heads,
+          args.save_interval,
+          args.save_path,
+          device,
+          args.learning_rate,
+          args.max_grad_norm,
+          args.weight_decay)
+
+if __name__ == "__main__":
+  main()
Author	SHA1	Message	Date
Phil Wang	ad87bfe28f	switch to using linear attention for the sparse attention layers within unet, given success in GAN projects	2022-05-01 17:59:03 -07:00
Phil Wang	76c767b1ce	update deps, commit to using webdatasets, per @rom1504 consultation	2022-05-01 12:22:15 -07:00
Phil Wang	d991b8c39c	just clip the diffusion prior network parameters	2022-05-01 12:01:08 -07:00
Phil Wang	902693e271	todo	2022-05-01 11:57:08 -07:00
Phil Wang	35cd63982d	add gradient clipping, make sure weight decay is configurable, make sure learning rate is actually passed into get_optimizer, make sure model is set to training mode at beginning of each epoch	2022-05-01 11:55:38 -07:00
Kumar R	53ce6dfdf6	All changes implemented, current run happening. Link to wandb run in comments. (#43 ) * Train DiffusionPrior with pre-computed embeddings This is in response to https://github.com/lucidrains/DALLE2-pytorch/issues/29 - more metrics will get added.	2022-05-01 11:46:59 -07:00
Phil Wang	ad8d7a368b	product management	2022-05-01 11:26:21 -07:00
Phil Wang	b8cf1e5c20	more attention	2022-05-01 11:00:33 -07:00
Phil Wang	94aaa08d97	product management	2022-05-01 09:43:10 -07:00
Phil Wang	8b9bbec7d1	project management	2022-05-01 09:32:57 -07:00
Phil Wang	1bb9fc9829	add convnext backbone for vqgan-vae, still need to fix groupnorms in resnet encdec	2022-05-01 09:32:24 -07:00
Phil Wang	5e421bd5bb	let researchers do the hyperparameter search	2022-05-01 08:46:21 -07:00
Phil Wang	67fcab1122	add MLP based time conditioning to all convnexts, in addition to cross attention. also add an initial convolution, given convnext first depthwise conv	2022-05-01 08:41:02 -07:00
Phil Wang	5bfbccda22	port over vqgan vae trainer	2022-05-01 08:09:15 -07:00
Phil Wang	989275ff59	product management	2022-04-30 16:57:56 -07:00
Phil Wang	56408f4a40	project management	2022-04-30 16:57:02 -07:00
Phil Wang	d1a697ac23	allows one to shortcut sampling at a specific unet number, if one were to be training in stages	2022-04-30 16:05:13 -07:00
Phil Wang	ebe01749ed	DecoderTrainer sample method uses the exponentially moving averaged	2022-04-30 14:55:34 -07:00
Phil Wang	63195cc2cb	allow for division of loss prior to scaling, for gradient accumulation purposes	2022-04-30 12:56:47 -07:00
Phil Wang	a2ef69af66	take care of mixed precision, and make gradient accumulation do-able externally	2022-04-30 12:27:24 -07:00
Phil Wang	5fff22834e	be able to finely customize learning parameters for each unet, take care of gradient clipping	2022-04-30 11:56:05 -07:00
Phil Wang	a9421f49ec	simplify Decoder training for the public	2022-04-30 11:45:18 -07:00
Phil Wang	77fa34eae9	fix all clipping / clamping issues	2022-04-30 10:08:24 -07:00
Phil Wang	1c1e508369	fix all issues with text encodings conditioning in the decoder, using null padding tokens technique from dalle v1	2022-04-30 09:13:34 -07:00
Phil Wang	f19c99ecb0	fix decoder needing separate conditional dropping probabilities for image embeddings and text encodings, thanks to @xiankgx !	2022-04-30 08:48:05 -07:00
Phil Wang	721a444686	Merge pull request #37 from ProGamerGov/patch-1 Fix spelling and grammatical errors	2022-04-30 08:19:07 -07:00
ProGamerGov	63450b466d	Fix spelling and grammatical errors	2022-04-30 09:18:13 -06:00
Phil Wang	20e7eb5a9b	cleanup	2022-04-30 07:22:57 -07:00
Phil Wang	e2f9615afa	use @clip-anytorch , thanks to @rom1504	2022-04-30 06:40:54 -07:00
Phil Wang	0d1c07c803	fix a bug with classifier free guidance, thanks to @xiankgx again!	2022-04-30 06:34:57 -07:00
Phil Wang	a389f81138	todo	2022-04-29 15:40:51 -07:00
Phil Wang	0283556608	fix example in readme, since api changed	2022-04-29 13:40:55 -07:00
Phil Wang	5063d192b6	now completely OpenAI CLIP compatible for training just take care of the logic for AdamW and transformers used namedtuples for clip adapter embedding outputs	2022-04-29 13:05:01 -07:00
Phil Wang	f4a54e475e	add some training fns	2022-04-29 09:44:55 -07:00
Phil Wang	fb662a62f3	fix another bug thanks to @xiankgx	2022-04-29 07:38:32 -07:00
Phil Wang	587c8c9b44	optimize for clarity	2022-04-28 21:59:13 -07:00
Phil Wang	aa900213e7	force first unet in the cascade to be conditioned on image embeds	2022-04-28 20:53:15 -07:00
Phil Wang	cb26187450	vqgan-vae codebook dims should be 256 or smaller	2022-04-28 08:59:03 -07:00
Phil Wang	625ce23f6b	🐛	2022-04-28 07:21:18 -07:00
Phil Wang	dbf4a281f1	make sure another CLIP can actually be passed in, as long as it is wrapped in an adapter extended from BaseClipAdapter	2022-04-27 20:45:27 -07:00
Phil Wang	4ab527e779	some extra asserts for text encoding of diffusion prior and decoder	2022-04-27 20:11:43 -07:00
Phil Wang	d0cdeb3247	add ability for DALL-E2 to return PIL images with `return_pil_images = True` on forward, for those who have no clue about deep learning	2022-04-27 19:58:06 -07:00
Phil Wang	8c610aad9a	only pass text encodings conditioning in diffusion prior if specified on initialization	2022-04-27 19:48:16 -07:00
Phil Wang	6700381a37	prepare for ability to integrate other clips other than x-clip	2022-04-27 19:35:05 -07:00
Phil Wang	20377f889a	todo	2022-04-27 17:22:14 -07:00
Phil Wang	6edb1c5dd0	fix issue with ema class	2022-04-27 16:40:02 -07:00
Phil Wang	b093f92182	inform what is possible	2022-04-27 08:25:16 -07:00
Phil Wang	fa3bb6ba5c	make sure cpu-only still works	2022-04-27 08:02:10 -07:00
Phil Wang	2705e7c9b0	attention-based upsampling claims unsupported by local experiments, removing	2022-04-27 07:51:04 -07:00