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177 lines
5.2 KiB
177 lines
5.2 KiB
import torch |
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from torch import FloatTensor, LongTensor |
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from torch.nn import Module, ModuleList, GroupNorm, Conv2d, Embedding |
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class ResnetBlock(Module): |
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def __init__(self, log2_count_in: int, log2_count_out: int): |
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super().__init__() |
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m, n = 2 ** log2_count_in, 2 ** log2_count_out |
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self.is_middle = m == n |
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self.norm1 = GroupNorm(2 ** 5, m) |
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self.conv1 = Conv2d(m, n, 3, padding=1) |
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self.norm2 = GroupNorm(2 ** 5, n) |
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self.conv2 = Conv2d(n, n, 3, padding=1) |
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if not self.is_middle: |
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self.nin_shortcut = Conv2d(m, n, 1) |
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def forward(self, x: FloatTensor) -> FloatTensor: |
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h = x |
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h = self.norm1.forward(h) |
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h *= torch.sigmoid(h) |
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h = self.conv1.forward(h) |
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h = self.norm2.forward(h) |
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h *= torch.sigmoid(h) |
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h = self.conv2(h) |
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if not self.is_middle: |
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x = self.nin_shortcut.forward(x) |
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return x + h |
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class AttentionBlock(Module): |
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def __init__(self): |
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super().__init__() |
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n = 2 ** 9 |
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self.norm = GroupNorm(2 ** 5, n) |
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self.q = Conv2d(n, n, 1) |
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self.k = Conv2d(n, n, 1) |
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self.v = Conv2d(n, n, 1) |
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self.proj_out = Conv2d(n, n, 1) |
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def forward(self, x: FloatTensor) -> FloatTensor: |
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n, m = 2 ** 9, x.shape[0] |
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h = x |
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h = self.norm(h) |
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q = self.q.forward(h) |
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k = self.k.forward(h) |
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v = self.v.forward(h) |
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q = q.reshape(m, n, 2 ** 8) |
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q = q.permute(0, 2, 1) |
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k = k.reshape(m, n, 2 ** 8) |
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w = torch.bmm(q, k) |
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w /= n ** 0.5 |
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w = torch.softmax(w, dim=2) |
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v = v.reshape(m, n, 2 ** 8) |
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w = w.permute(0, 2, 1) |
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h = torch.bmm(v, w) |
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h = h.reshape(m, n, 2 ** 4, 2 ** 4) |
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h = self.proj_out.forward(h) |
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return x + h |
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class MiddleLayer(Module): |
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def __init__(self): |
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super().__init__() |
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self.block_1 = ResnetBlock(9, 9) |
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self.attn_1 = AttentionBlock() |
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self.block_2 = ResnetBlock(9, 9) |
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def forward(self, h: FloatTensor) -> FloatTensor: |
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h = self.block_1.forward(h) |
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h = self.attn_1.forward(h) |
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h = self.block_2.forward(h) |
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return h |
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class Upsample(Module): |
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def __init__(self, log2_count): |
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super().__init__() |
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n = 2 ** log2_count |
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self.upsample = torch.nn.UpsamplingNearest2d(scale_factor=2) |
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self.conv = Conv2d(n, n, 3, padding=1) |
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def forward(self, x: FloatTensor) -> FloatTensor: |
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x = self.upsample.forward(x.to(torch.float32)) |
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x = self.conv.forward(x) |
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return x |
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class UpsampleBlock(Module): |
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def __init__( |
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self, |
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log2_count_in: int, |
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log2_count_out: int, |
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has_attention: bool, |
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has_upsample: bool |
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): |
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super().__init__() |
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self.has_attention = has_attention |
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self.has_upsample = has_upsample |
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self.block = ModuleList([ |
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ResnetBlock(log2_count_in, log2_count_out), |
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ResnetBlock(log2_count_out, log2_count_out), |
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ResnetBlock(log2_count_out, log2_count_out) |
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]) |
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if has_attention: |
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self.attn = ModuleList([ |
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AttentionBlock(), |
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AttentionBlock(), |
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AttentionBlock() |
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]) |
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else: |
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self.attn = ModuleList() |
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if has_upsample: |
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self.upsample = Upsample(log2_count_out) |
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def forward(self, h: FloatTensor) -> FloatTensor: |
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for j in range(3): |
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h = self.block[j].forward(h) |
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if self.has_attention: |
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h = self.attn[j].forward(h) |
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if self.has_upsample: |
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h = self.upsample.forward(h) |
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return h |
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class Decoder(Module): |
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def __init__(self): |
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super().__init__() |
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self.conv_in = Conv2d(2 ** 8, 2 ** 9, 3, padding=1) |
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self.mid = MiddleLayer() |
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self.up = ModuleList([ |
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UpsampleBlock(7, 7, False, False), |
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UpsampleBlock(8, 7, False, True), |
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UpsampleBlock(8, 8, False, True), |
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UpsampleBlock(9, 8, False, True), |
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UpsampleBlock(9, 9, True, True) |
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]) |
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self.norm_out = GroupNorm(2 ** 5, 2 ** 7) |
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self.conv_out = Conv2d(2 ** 7, 3, 3, padding=1) |
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def forward(self, z: FloatTensor) -> FloatTensor: |
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z = self.conv_in.forward(z) |
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z = self.mid.forward(z) |
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for i in reversed(range(5)): |
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z = self.up[i].forward(z) |
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z = self.norm_out.forward(z) |
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z *= torch.sigmoid(z) |
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z = self.conv_out.forward(z) |
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return z |
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class VQGanDetokenizer(Module): |
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def __init__(self): |
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super().__init__() |
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vocab_count, embed_count = 2 ** 14, 2 ** 8 |
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self.vocab_count = vocab_count |
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self.embedding = Embedding(vocab_count, embed_count) |
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self.post_quant_conv = Conv2d(embed_count, embed_count, 1) |
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self.decoder = Decoder() |
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def forward(self, z: LongTensor) -> FloatTensor: |
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z = z.clamp(0, self.vocab_count - 1) |
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z = self.embedding.forward(z) |
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z = z.view((z.shape[0], 2 ** 4, 2 ** 4, 2 ** 8)) |
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z = z.permute(0, 3, 1, 2).contiguous() |
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z = self.post_quant_conv.forward(z) |
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z = self.decoder.forward(z) |
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z = z.permute(0, 2, 3, 1) |
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z = z.clip(0.0, 1.0) * 255 |
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return z
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