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__init__.py

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+import io, requests
+import torch
+import torch.nn as nn
+
+from dall_e.encoder import Encoder
+from dall_e.decoder import Decoder
+from dall_e.utils   import map_pixels, unmap_pixels
+
+def load_model(path: str, device: torch.device = None) -> nn.Module:
+    if path.startswith('http://') or path.startswith('https://'):
+        resp = requests.get(path)
+        resp.raise_for_status()
+            
+        with io.BytesIO(resp.content) as buf:
+            return torch.load(buf, map_location=device)
+    else:
+        with open(path, 'rb') as f:
+            return torch.load(f, map_location=device)

decoder.py

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+import attr
+import numpy as np
+
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+
+from collections  import OrderedDict
+from functools    import partial
+from dall_e.utils import Conv2d
+
+@attr.s(eq=False, repr=False)
+class DecoderBlock(nn.Module):
+	n_in:     int = attr.ib(validator=lambda i, a, x: x >= 1)
+	n_out:    int = attr.ib(validator=lambda i, a, x: x >= 1 and x % 4 ==0)
+	n_layers: int = attr.ib(validator=lambda i, a, x: x >= 1)
+
+	device:        torch.device = attr.ib(default=None)
+	requires_grad: bool         = attr.ib(default=False)
+
+	def __attrs_post_init__(self) -> None:
+		super().__init__()
+		self.n_hid = self.n_out // 4
+		self.post_gain = 1 / (self.n_layers ** 2)
+
+		make_conv     = partial(Conv2d, device=self.device, requires_grad=self.requires_grad)
+		self.id_path  = make_conv(self.n_in, self.n_out, 1) if self.n_in != self.n_out else nn.Identity()
+		self.res_path = nn.Sequential(OrderedDict([
+				('relu_1', nn.ReLU()),
+				('conv_1', make_conv(self.n_in,  self.n_hid, 1)),
+				('relu_2', nn.ReLU()),
+				('conv_2', make_conv(self.n_hid, self.n_hid, 3)),
+				('relu_3', nn.ReLU()),
+				('conv_3', make_conv(self.n_hid, self.n_hid, 3)),
+				('relu_4', nn.ReLU()),
+				('conv_4', make_conv(self.n_hid, self.n_out, 3)),]))
+
+	def forward(self, x: torch.Tensor) -> torch.Tensor:
+		return self.id_path(x) + self.post_gain * self.res_path(x)
+
+@attr.s(eq=False, repr=False)
+class Decoder(nn.Module):
+	group_count:     int = 4
+	n_init:          int = attr.ib(default=128,  validator=lambda i, a, x: x >= 8)
+	n_hid:           int = attr.ib(default=256,  validator=lambda i, a, x: x >= 64)
+	n_blk_per_group: int = attr.ib(default=2,    validator=lambda i, a, x: x >= 1)
+	output_channels: int = attr.ib(default=3,    validator=lambda i, a, x: x >= 1)
+	vocab_size:      int = attr.ib(default=8192, validator=lambda i, a, x: x >= 512)
+
+	device:              torch.device = attr.ib(default=torch.device('cpu'))
+	requires_grad:       bool         = attr.ib(default=False)
+	use_mixed_precision: bool         = attr.ib(default=True)
+
+	def __attrs_post_init__(self) -> None:
+		super().__init__()
+
+		blk_range  = range(self.n_blk_per_group)
+		n_layers   = self.group_count * self.n_blk_per_group
+		make_conv  = partial(Conv2d, device=self.device, requires_grad=self.requires_grad)
+		make_blk   = partial(DecoderBlock, n_layers=n_layers, device=self.device,
+				requires_grad=self.requires_grad)
+
+		self.blocks = nn.Sequential(OrderedDict([
+			('input', make_conv(self.vocab_size, self.n_init, 1, use_float16=False)),
+			('group_1', nn.Sequential(OrderedDict([
+				*[(f'block_{i + 1}', make_blk(self.n_init if i == 0 else 8 * self.n_hid, 8 * self.n_hid)) for i in blk_range],
+				('upsample', nn.Upsample(scale_factor=2, mode='nearest')),
+			]))),
+			('group_2', nn.Sequential(OrderedDict([
+				*[(f'block_{i + 1}', make_blk(8 * self.n_hid if i == 0 else 4 * self.n_hid, 4 * self.n_hid)) for i in blk_range],
+				('upsample', nn.Upsample(scale_factor=2, mode='nearest')),
+			]))),
+			('group_3', nn.Sequential(OrderedDict([
+				*[(f'block_{i + 1}', make_blk(4 * self.n_hid if i == 0 else 2 * self.n_hid, 2 * self.n_hid)) for i in blk_range],
+				('upsample', nn.Upsample(scale_factor=2, mode='nearest')),
+			]))),
+			('group_4', nn.Sequential(OrderedDict([
+				*[(f'block_{i + 1}', make_blk(2 * self.n_hid if i == 0 else 1 * self.n_hid, 1 * self.n_hid)) for i in blk_range],
+			]))),
+			('output', nn.Sequential(OrderedDict([
+				('relu', nn.ReLU()),
+				('conv', make_conv(1 * self.n_hid, 2 * self.output_channels, 1)),
+			]))),
+		]))
+
+	def forward(self, x: torch.Tensor) -> torch.Tensor:
+		if len(x.shape) != 4:
+			raise ValueError(f'input shape {x.shape} is not 4d')
+		if x.shape[1] != self.vocab_size:
+			raise ValueError(f'input has {x.shape[1]} channels but model built for {self.vocab_size}')
+		if x.dtype != torch.float32:
+			raise ValueError('input must have dtype torch.float32')
+
+		return self.blocks(x)

encoder.py

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+import attr
+import numpy as np
+
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+
+from collections  import OrderedDict
+from functools    import partial
+from dall_e.utils import Conv2d
+
+@attr.s(eq=False, repr=False)
+class EncoderBlock(nn.Module):
+	n_in:     int = attr.ib(validator=lambda i, a, x: x >= 1)
+	n_out:    int = attr.ib(validator=lambda i, a, x: x >= 1 and x % 4 ==0)
+	n_layers: int = attr.ib(validator=lambda i, a, x: x >= 1)
+
+	device:        torch.device = attr.ib(default=None)
+	requires_grad: bool         = attr.ib(default=False)
+
+	def __attrs_post_init__(self) -> None:
+		super().__init__()
+		self.n_hid = self.n_out // 4
+		self.post_gain = 1 / (self.n_layers ** 2)
+
+		make_conv     = partial(Conv2d, device=self.device, requires_grad=self.requires_grad)
+		self.id_path  = make_conv(self.n_in, self.n_out, 1) if self.n_in != self.n_out else nn.Identity()
+		self.res_path = nn.Sequential(OrderedDict([
+				('relu_1', nn.ReLU()),
+				('conv_1', make_conv(self.n_in,  self.n_hid, 3)),
+				('relu_2', nn.ReLU()),
+				('conv_2', make_conv(self.n_hid, self.n_hid, 3)),
+				('relu_3', nn.ReLU()),
+				('conv_3', make_conv(self.n_hid, self.n_hid, 3)),
+				('relu_4', nn.ReLU()),
+				('conv_4', make_conv(self.n_hid, self.n_out, 1)),]))
+
+	def forward(self, x: torch.Tensor) -> torch.Tensor:
+		return self.id_path(x) + self.post_gain * self.res_path(x)
+
+@attr.s(eq=False, repr=False)
+class Encoder(nn.Module):
+	group_count:     int = 4
+	n_hid:           int = attr.ib(default=256,  validator=lambda i, a, x: x >= 64)
+	n_blk_per_group: int = attr.ib(default=2,    validator=lambda i, a, x: x >= 1)
+	input_channels:  int = attr.ib(default=3,    validator=lambda i, a, x: x >= 1)
+	vocab_size:      int = attr.ib(default=8192, validator=lambda i, a, x: x >= 512)
+
+	device:              torch.device = attr.ib(default=torch.device('cpu'))
+	requires_grad:       bool         = attr.ib(default=False)
+	use_mixed_precision: bool         = attr.ib(default=True)
+
+	def __attrs_post_init__(self) -> None:
+		super().__init__()
+
+		blk_range  = range(self.n_blk_per_group)
+		n_layers   = self.group_count * self.n_blk_per_group
+		make_conv  = partial(Conv2d, device=self.device, requires_grad=self.requires_grad)
+		make_blk   = partial(EncoderBlock, n_layers=n_layers, device=self.device,
+				requires_grad=self.requires_grad)
+
+		self.blocks = nn.Sequential(OrderedDict([
+			('input', make_conv(self.input_channels, 1 * self.n_hid, 7)),
+			('group_1', nn.Sequential(OrderedDict([
+				*[(f'block_{i + 1}', make_blk(1 * self.n_hid, 1 * self.n_hid)) for i in blk_range],
+				('pool', nn.MaxPool2d(kernel_size=2)),
+			]))),
+			('group_2', nn.Sequential(OrderedDict([
+				*[(f'block_{i + 1}', make_blk(1 * self.n_hid if i == 0 else 2 * self.n_hid, 2 * self.n_hid)) for i in blk_range],
+				('pool', nn.MaxPool2d(kernel_size=2)),
+			]))),
+			('group_3', nn.Sequential(OrderedDict([
+				*[(f'block_{i + 1}', make_blk(2 * self.n_hid if i == 0 else 4 * self.n_hid, 4 * self.n_hid)) for i in blk_range],
+				('pool', nn.MaxPool2d(kernel_size=2)),
+			]))),
+			('group_4', nn.Sequential(OrderedDict([
+				*[(f'block_{i + 1}', make_blk(4 * self.n_hid if i == 0 else 8 * self.n_hid, 8 * self.n_hid)) for i in blk_range],
+			]))),
+			('output', nn.Sequential(OrderedDict([
+				('relu', nn.ReLU()),
+				('conv', make_conv(8 * self.n_hid, self.vocab_size, 1, use_float16=False)),
+			]))),
+		]))
+
+	def forward(self, x: torch.Tensor) -> torch.Tensor:
+		if len(x.shape) != 4:
+			raise ValueError(f'input shape {x.shape} is not 4d')
+		if x.shape[1] != self.input_channels:
+			raise ValueError(f'input has {x.shape[1]} channels but model built for {self.input_channels}')
+		if x.dtype != torch.float32:
+			raise ValueError('input must have dtype torch.float32')
+
+		return self.blocks(x)

utils.py

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+import attr
+import math
+
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+
+logit_laplace_eps: float = 0.1
+
+@attr.s(eq=False)
+class Conv2d(nn.Module):
+	n_in:  int = attr.ib(validator=lambda i, a, x: x >= 1)
+	n_out: int = attr.ib(validator=lambda i, a, x: x >= 1)
+	kw:    int = attr.ib(validator=lambda i, a, x: x >= 1 and x % 2 == 1)
+
+	use_float16:   bool         = attr.ib(default=True)
+	device:        torch.device = attr.ib(default=torch.device('cpu'))
+	requires_grad: bool         = attr.ib(default=False)
+
+	def __attrs_post_init__(self) -> None:
+		super().__init__()
+
+		w = torch.empty((self.n_out, self.n_in, self.kw, self.kw), dtype=torch.float32,
+			device=self.device, requires_grad=self.requires_grad)
+		w.normal_(std=1 / math.sqrt(self.n_in * self.kw ** 2))
+
+		b = torch.zeros((self.n_out,), dtype=torch.float32, device=self.device,
+			requires_grad=self.requires_grad)
+		self.w, self.b = nn.Parameter(w), nn.Parameter(b)
+
+	def forward(self, x: torch.Tensor) -> torch.Tensor:
+		if self.use_float16 and 'cuda' in self.w.device.type:
+			if x.dtype != torch.float16:
+				x = x.half()
+
+			w, b = self.w.half(), self.b.half()
+		else:
+			if x.dtype != torch.float32:
+				x = x.float()
+
+			w, b = self.w, self.b
+
+		return F.conv2d(x, w, b, padding=(self.kw - 1) // 2)
+
+def map_pixels(x: torch.Tensor) -> torch.Tensor:
+	if len(x.shape) != 4:
+		raise ValueError('expected input to be 4d')
+	if x.dtype != torch.float:
+		raise ValueError('expected input to have type float')
+
+	return (1 - 2 * logit_laplace_eps) * x + logit_laplace_eps
+
+def unmap_pixels(x: torch.Tensor) -> torch.Tensor:
+	if len(x.shape) != 4:
+		raise ValueError('expected input to be 4d')
+	if x.dtype != torch.float:
+		raise ValueError('expected input to have type float')
+
+	return torch.clamp((x - logit_laplace_eps) / (1 - 2 * logit_laplace_eps), 0, 1)