add gradient checkpointing for all resnet blocks

README.md

@@ -627,6 +627,18 @@ images = dalle2(
 # save your image (in this example, of size 256x256)
 ```
 
+Alternatively, you can also use <a href="https://github.com/mlfoundations/open_clip">Open Clip</a>
+
+```bash
+$ pip install open-clip-torch
+```
+
+```python
+from dalle2_pytorch import OpenClipAdapter
+
+clip = OpenClipAdapter()
+```
+
 Now you'll just have to worry about training the Prior and the Decoder!
 
 ## Inpainting

dalle2_pytorch/dalle2_pytorch.py

@@ -8,6 +8,7 @@ from pathlib import Path
 
 import torch
 import torch.nn.functional as F
+from torch.utils.checkpoint import checkpoint
 from torch import nn, einsum
 import torchvision.transforms as T
 
@@ -108,6 +109,28 @@ def pad_tuple_to_length(t, length, fillvalue = None):
         return t
     return (*t, *((fillvalue,) * remain_length))
 
+# checkpointing helper function
+
+def make_checkpointable(fn, **kwargs):
+    if isinstance(fn, nn.ModuleList):
+        return [maybe(make_checkpointable)(el, **kwargs) for el in fn]
+
+    condition = kwargs.pop('condition', None)
+
+    if exists(condition) and not condition(fn):
+        return fn
+
+    @wraps(fn)
+    def inner(*args):
+        input_needs_grad = any([isinstance(el, torch.Tensor) and el.requires_grad for el in args])
+
+        if not input_needs_grad:
+            return fn(*args)
+
+        return checkpoint(fn, *args)
+
+    return inner
+
 # for controlling freezing of CLIP
 
 def set_module_requires_grad_(module, requires_grad):
@@ -339,6 +362,75 @@ class OpenAIClipAdapter(BaseClipAdapter):
         image_embed = self.clip.encode_image(image)
         return EmbeddedImage(l2norm(image_embed.float()), None)
 
+class OpenClipAdapter(BaseClipAdapter):
+    def __init__(
+        self,
+        name = 'ViT-B/32',
+        pretrained = 'laion400m_e32'
+    ):
+        import open_clip
+        clip, _, preprocess = open_clip.create_model_and_transforms(name, pretrained = pretrained)
+
+        super().__init__(clip)
+        self.eos_id = 49407
+
+        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.image_size
+
+    @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]
+
+        is_eos_id = (text == self.eos_id)
+        text_mask_excluding_eos = is_eos_id.cumsum(dim = -1) == 0
+        text_mask = F.pad(text_mask_excluding_eos, (1, -1), value = True)
+        assert not self.cleared
+
+        text_embed = self.clip.encode_text(text)
+        text_encodings = self.text_encodings
+        text_encodings = text_encodings.masked_fill(~text_mask[..., None], 0.)
+        del self.text_encodings
+        return EmbeddedText(l2norm(text_embed.float()), text_encodings.float())
+
+    @torch.no_grad()
+    def embed_image(self, image):
+        assert not self.cleared
+        image = self.validate_and_resize_image(image)
+        image = self.clip_normalize(image)
+        image_embed = self.clip.encode_image(image)
+        return EmbeddedImage(l2norm(image_embed.float()), None)
+
 # classifier free guidance functions
 
 def prob_mask_like(shape, prob, device):
@@ -547,34 +639,40 @@ class NoiseScheduler(nn.Module):
 # diffusion prior
 
 class LayerNorm(nn.Module):
-    def __init__(self, dim, eps = 1e-5, stable = False):
+    def __init__(self, dim, eps = 1e-5, fp16_eps = 1e-3, stable = False):
         super().__init__()
         self.eps = eps
+        self.fp16_eps = fp16_eps
         self.stable = stable
         self.g = nn.Parameter(torch.ones(dim))
 
     def forward(self, x):
+        eps = self.eps if x.dtype == torch.float32 else self.fp16_eps
+
         if self.stable:
             x = x / x.amax(dim = -1, keepdim = True).detach()
 
         var = torch.var(x, dim = -1, unbiased = False, keepdim = True)
         mean = torch.mean(x, dim = -1, keepdim = True)
-        return (x - mean) * (var + self.eps).rsqrt() * self.g
+        return (x - mean) * (var + eps).rsqrt() * self.g
 
 class ChanLayerNorm(nn.Module):
-    def __init__(self, dim, eps = 1e-5, stable = False):
+    def __init__(self, dim, eps = 1e-5, fp16_eps = 1e-3, stable = False):
         super().__init__()
         self.eps = eps
+        self.fp16_eps = fp16_eps
         self.stable = stable
         self.g = nn.Parameter(torch.ones(1, dim, 1, 1))
 
     def forward(self, x):
+        eps = self.eps if x.dtype == torch.float32 else self.fp16_eps
+
         if self.stable:
             x = x / x.amax(dim = 1, keepdim = True).detach()
 
         var = torch.var(x, dim = 1, unbiased = False, keepdim = True)
         mean = torch.mean(x, dim = 1, keepdim = True)
-        return (x - mean) * (var + self.eps).rsqrt() * self.g
+        return (x - mean) * (var + eps).rsqrt() * self.g
 
 class Residual(nn.Module):
     def __init__(self, fn):
@@ -695,11 +793,12 @@ class Attention(nn.Module):
         dropout = 0.,
         causal = False,
         rotary_emb = None,
-        pb_relax_alpha = 128
+        cosine_sim = True,
+        cosine_sim_scale = 16
     ):
         super().__init__()
-        self.pb_relax_alpha = pb_relax_alpha
-        self.scale = dim_head ** -0.5 * (pb_relax_alpha ** -1)
+        self.scale = cosine_sim_scale if cosine_sim else (dim_head ** -0.5)
+        self.cosine_sim = cosine_sim
 
         self.heads = heads
         inner_dim = dim_head * heads
@@ -739,6 +838,13 @@ class Attention(nn.Module):
         k = torch.cat((nk, k), dim = -2)
         v = torch.cat((nv, v), dim = -2)
 
+        # whether to use cosine sim
+
+        if self.cosine_sim:
+            q, k = map(l2norm, (q, k))
+
+        q, k = map(lambda t: t * math.sqrt(self.scale), (q, k))
+
         # calculate query / key similarities
 
         sim = einsum('b h i d, b j d -> b h i j', q, k)
@@ -764,9 +870,6 @@ class Attention(nn.Module):
 
         # attention
 
-        sim = sim - sim.amax(dim = -1, keepdim = True).detach()
-        sim = sim * self.pb_relax_alpha
-
         attn = sim.softmax(dim = -1)
         attn = self.dropout(attn)
 
@@ -1357,7 +1460,8 @@ class ResnetBlock(nn.Module):
         *,
         cond_dim = None,
         time_cond_dim = None,
-        groups = 8
+        groups = 8,
+        cosine_sim_cross_attn = False
     ):
         super().__init__()
 
@@ -1377,7 +1481,8 @@ class ResnetBlock(nn.Module):
                 'b (h w) c',
                 CrossAttention(
                     dim = dim_out,
-                    context_dim = cond_dim
+                    context_dim = cond_dim,
+                    cosine_sim = cosine_sim_cross_attn
                 )
             )
 
@@ -1412,11 +1517,12 @@ class CrossAttention(nn.Module):
         heads = 8,
         dropout = 0.,
         norm_context = False,
-        pb_relax_alpha = 32 ** 2
+        cosine_sim = False,
+        cosine_sim_scale = 16
     ):
         super().__init__()
-        self.pb_relax_alpha = pb_relax_alpha
-        self.scale = dim_head ** -0.5 * (pb_relax_alpha ** -1)
+        self.cosine_sim = cosine_sim
+        self.scale = cosine_sim_scale if cosine_sim else (dim_head ** -0.5)
         self.heads = heads
         inner_dim = dim_head * heads
 
@@ -1452,7 +1558,10 @@ class CrossAttention(nn.Module):
         k = torch.cat((nk, k), dim = -2)
         v = torch.cat((nv, v), dim = -2)
 
-        q = q * self.scale
+        if self.cosine_sim:
+            q, k = map(l2norm, (q, k))
+
+        q, k = map(lambda t: t * math.sqrt(self.scale), (q, k))
 
         sim = einsum('b h i d, b h j d -> b h i j', q, k)
         max_neg_value = -torch.finfo(sim.dtype).max
@@ -1462,9 +1571,6 @@ class CrossAttention(nn.Module):
             mask = rearrange(mask, 'b j -> b 1 1 j')
             sim = sim.masked_fill(~mask, max_neg_value)
 
-        sim = sim - sim.amax(dim = -1, keepdim = True).detach()
-        sim = sim * self.pb_relax_alpha
-
         attn = sim.softmax(dim = -1)
 
         out = einsum('b h i j, b h j d -> b h i d', attn, v)
@@ -1476,7 +1582,8 @@ class LinearAttention(nn.Module):
         self,
         dim,
         dim_head = 32,
-        heads = 8
+        heads = 8,
+        **kwargs
     ):
         super().__init__()
         self.scale = dim_head ** -0.5
@@ -1494,6 +1601,7 @@ class LinearAttention(nn.Module):
 
     def forward(self, fmap):
         h, x, y = self.heads, *fmap.shape[-2:]
+        seq_len = x * y
 
         fmap = self.norm(fmap)
         q, k, v = self.to_qkv(fmap).chunk(3, dim = 1)
@@ -1503,7 +1611,9 @@ class LinearAttention(nn.Module):
         k = k.softmax(dim = -2)
 
         q = q * self.scale
-        v = v / (x * y)
+        v = l2norm(v)
+
+        k, v = map(lambda t: t / math.sqrt(seq_len), (k, v))
 
         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)
@@ -1591,6 +1701,8 @@ class Unet(nn.Module):
         lowres_cond = False,             # for cascading diffusion - https://cascaded-diffusion.github.io/
         lowres_noise_cond = False,       # for conditioning on low resolution noising, based on Imagen
         sparse_attn = False,
+        cosine_sim_cross_attn = False,
+        cosine_sim_self_attn = False,
         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,
@@ -1609,6 +1721,7 @@ class Unet(nn.Module):
         pixel_shuffle_upsample = True,
         final_conv_kernel_size = 1,
         combine_upsample_fmaps = False, # whether to combine the outputs of all upsample blocks, as in unet squared paper
+        checkpoint_during_training = False,
         **kwargs
     ):
         super().__init__()
@@ -1711,7 +1824,7 @@ class Unet(nn.Module):
 
         # attention related params
 
-        attn_kwargs = dict(heads = attn_heads, dim_head = attn_dim_head)
+        attn_kwargs = dict(heads = attn_heads, dim_head = attn_dim_head, cosine_sim = cosine_sim_self_attn)
 
         self_attn = cast_tuple(self_attn, num_stages)
 
@@ -1734,9 +1847,13 @@ class Unet(nn.Module):
 
         upsample_klass = NearestUpsample if not pixel_shuffle_upsample else PixelShuffleUpsample
 
+        # prepare resnet klass
+
+        resnet_block = partial(ResnetBlock, cosine_sim_cross_attn = cosine_sim_cross_attn)
+
         # give memory efficient unet an initial resnet block
 
-        self.init_resnet_block = ResnetBlock(init_dim, init_dim, time_cond_dim = time_cond_dim, groups = top_level_resnet_group) if memory_efficient else None
+        self.init_resnet_block = resnet_block(init_dim, init_dim, time_cond_dim = time_cond_dim, groups = top_level_resnet_group) if memory_efficient else None
 
         # layers
 
@@ -1763,17 +1880,17 @@ class Unet(nn.Module):
 
             self.downs.append(nn.ModuleList([
                 downsample_klass(dim_in, dim_out = dim_out) if memory_efficient else None,
-                ResnetBlock(dim_layer, dim_layer, time_cond_dim = time_cond_dim, groups = groups),
-                nn.ModuleList([ResnetBlock(dim_layer, dim_layer, cond_dim = layer_cond_dim, time_cond_dim = time_cond_dim, groups = groups) for _ in range(layer_num_resnet_blocks)]),
+                resnet_block(dim_layer, dim_layer, time_cond_dim = time_cond_dim, groups = groups),
+                nn.ModuleList([resnet_block(dim_layer, dim_layer, cond_dim = layer_cond_dim, time_cond_dim = time_cond_dim, groups = groups) for _ in range(layer_num_resnet_blocks)]),
                 attention,
                 downsample_klass(dim_layer, dim_out = dim_out) if not is_last and not memory_efficient else nn.Conv2d(dim_layer, dim_out, 1)
             ]))
 
         mid_dim = dims[-1]
 
-        self.mid_block1 = ResnetBlock(mid_dim, mid_dim, cond_dim = cond_dim, time_cond_dim = time_cond_dim, groups = resnet_groups[-1])
+        self.mid_block1 = resnet_block(mid_dim, mid_dim, cond_dim = cond_dim, time_cond_dim = time_cond_dim, groups = resnet_groups[-1])
         self.mid_attn = create_self_attn(mid_dim)
-        self.mid_block2 = ResnetBlock(mid_dim, mid_dim, cond_dim = cond_dim, time_cond_dim = time_cond_dim, groups = resnet_groups[-1])
+        self.mid_block2 = resnet_block(mid_dim, mid_dim, cond_dim = cond_dim, time_cond_dim = time_cond_dim, groups = resnet_groups[-1])
 
         for ind, ((dim_in, dim_out), groups, layer_num_resnet_blocks, layer_self_attn) in enumerate(zip(reversed(in_out), reversed(resnet_groups), reversed(num_resnet_blocks), reversed(self_attn))):
             is_last = ind >= (len(in_out) - 1)
@@ -1790,8 +1907,8 @@ class Unet(nn.Module):
             upsample_combiner_dims.append(dim_out)
 
             self.ups.append(nn.ModuleList([
-                ResnetBlock(dim_out + skip_connect_dim, dim_out, cond_dim = layer_cond_dim, time_cond_dim = time_cond_dim, groups = groups),
-                nn.ModuleList([ResnetBlock(dim_out + skip_connect_dim, dim_out, cond_dim = layer_cond_dim, time_cond_dim = time_cond_dim, groups = groups)  for _ in range(layer_num_resnet_blocks)]),
+                resnet_block(dim_out + skip_connect_dim, dim_out, cond_dim = layer_cond_dim, time_cond_dim = time_cond_dim, groups = groups),
+                nn.ModuleList([resnet_block(dim_out + skip_connect_dim, dim_out, cond_dim = layer_cond_dim, time_cond_dim = time_cond_dim, groups = groups)  for _ in range(layer_num_resnet_blocks)]),
                 attention,
                 upsample_klass(dim_out, dim_in) if not is_last or memory_efficient else nn.Identity()
             ]))
@@ -1807,7 +1924,7 @@ class Unet(nn.Module):
 
         # a final resnet block
 
-        self.final_resnet_block = ResnetBlock(self.upsample_combiner.dim_out + dim, dim, time_cond_dim = time_cond_dim, groups = top_level_resnet_group)
+        self.final_resnet_block = resnet_block(self.upsample_combiner.dim_out + dim, dim, time_cond_dim = time_cond_dim, groups = top_level_resnet_group)
 
         out_dim_in = dim + (channels if lowres_cond else 0)
 
@@ -1815,6 +1932,10 @@ class Unet(nn.Module):
 
         zero_init_(self.to_out) # since both OpenAI and @crowsonkb are doing it
 
+        # whether to checkpoint during training
+
+        self.checkpoint_during_training = checkpoint_during_training
+
     # if the current settings for the unet are not correct
     # for cascading DDPM, then reinit the unet with the right settings
     def cast_model_parameters(
@@ -1872,7 +1993,8 @@ class Unet(nn.Module):
         image_cond_drop_prob = 0.,
         text_cond_drop_prob = 0.,
         blur_sigma = None,
-        blur_kernel_size = None
+        blur_kernel_size = None,
+        disable_checkpoint = False
     ):
         batch_size, device = x.shape[0], x.device
 
@@ -1994,17 +2116,29 @@ class Unet(nn.Module):
         c = self.norm_cond(c)
         mid_c = self.norm_mid_cond(mid_c)
 
+        # gradient checkpointing
+
+        can_checkpoint = self.training and self.checkpoint_during_training and not disable_checkpoint
+        apply_checkpoint_fn = make_checkpointable if can_checkpoint else identity
+
+        # make checkpointable modules
+
+        init_resnet_block, mid_block1, mid_attn, mid_block2, final_resnet_block = [maybe(apply_checkpoint_fn)(module) for module in (self.init_resnet_block, self.mid_block1, self.mid_attn, self.mid_block2, self.final_resnet_block)]
+
+        can_checkpoint_cond = lambda m: isinstance(m, ResnetBlock)
+        downs, ups = [maybe(apply_checkpoint_fn)(m, condition = can_checkpoint_cond) for m in (self.downs, self.ups)]
+
         # initial resnet block
 
-        if exists(self.init_resnet_block):
-            x = self.init_resnet_block(x, t)
+        if exists(init_resnet_block):
+            x = init_resnet_block(x, t)
 
         # go through the layers of the unet, down and up
 
         down_hiddens = []
         up_hiddens = []
 
-        for pre_downsample, init_block, resnet_blocks, attn, post_downsample in self.downs:
+        for pre_downsample, init_block, resnet_blocks, attn, post_downsample in downs:
             if exists(pre_downsample):
                 x = pre_downsample(x)
 
@@ -2020,16 +2154,16 @@ class Unet(nn.Module):
             if exists(post_downsample):
                 x = post_downsample(x)
 
-        x = self.mid_block1(x, t, mid_c)
+        x = mid_block1(x, t, mid_c)
 
-        if exists(self.mid_attn):
-            x = self.mid_attn(x)
+        if exists(mid_attn):
+            x = mid_attn(x)
 
-        x = self.mid_block2(x, t, mid_c)
+        x = mid_block2(x, t, mid_c)
 
         connect_skip = lambda fmap: torch.cat((fmap, down_hiddens.pop() * self.skip_connect_scale), dim = 1)
 
-        for init_block, resnet_blocks, attn, upsample in self.ups:
+        for init_block, resnet_blocks, attn, upsample in ups:
             x = connect_skip(x)
             x = init_block(x, t, c)
 
@@ -2046,7 +2180,7 @@ class Unet(nn.Module):
 
         x = torch.cat((x, r), dim = 1)
 
-        x = self.final_resnet_block(x, t)
+        x = final_resnet_block(x, t)
 
         if exists(lowres_cond_img):
             x = torch.cat((x, lowres_cond_img), dim = 1)

dalle2_pytorch/version.py

@@ -1 +1 @@
-__version__ = '1.2.2'
+__version__ = '1.5.0'

setup.py

@@ -26,7 +26,7 @@ setup(
   install_requires=[
     'accelerate',
     'click',
-    'clip-anytorch',
+    'clip-anytorch>=2.4.0',
     'coca-pytorch>=0.0.5',
     'ema-pytorch>=0.0.7',
     'einops>=0.4',