Commit
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411bad7
1
Parent(s):
7e639df
Update app.py
Browse filesremoved the redundant part
app.py
CHANGED
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@@ -24,106 +24,6 @@ sqrt_alphas_cumprod = torch.sqrt(alphas_cumprod)
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sqrt_one_minus_alphas_cumprod = torch.sqrt(1. - alphas_cumprod)
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posterior_variance = betas * (1. - alphas_cumprod_prev) / (1. - alphas_cumprod)
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class Block(nn.Module):
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def __init__(self, in_ch, out_ch, time_emb_dim, up=False):
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super().__init__()
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self.time_mlp = nn.Linear(time_emb_dim, out_ch)
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if up:
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self.conv1 = nn.Conv2d(2*in_ch, out_ch, 3, padding=1)
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self.transform = nn.ConvTranspose2d(out_ch, out_ch, 4, 2, 1)
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self.Upsample = nn.Upsample(scale_factor = 2, mode ='bilinear')
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else:
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self.conv1 = nn.Conv2d(in_ch, out_ch, 3, padding=1)
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self.transform = nn.Conv2d(out_ch, out_ch, 4, 2, 1)
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self.maxpool = nn.MaxPool2d(4, 2, 1)
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self.conv2 = nn.Conv2d(out_ch, out_ch, 3, padding=1)
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self.bnorm1 = nn.BatchNorm2d(out_ch)
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self.bnorm2 = nn.BatchNorm2d(out_ch)
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self.silu = nn.SiLU()
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self.relu = nn.ReLU()
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def forward(self, x, t, ):
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# First Conv
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h = (self.silu(self.bnorm1(self.conv1(x))))
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# Time embedding
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time_emb = self.relu(self.time_mlp(t))
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# Extend last 2 dimensions
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time_emb = time_emb[(..., ) + (None, ) * 2]
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# Add time channel
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h = h + time_emb
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# Second Conv
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h = (self.silu(self.bnorm2(self.conv2(h))))
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# Down or Upsample
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return self.transform(h)
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class SinusoidalPositionEmbeddings(nn.Module):
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def __init__(self, dim):
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super().__init__()
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self.dim = dim
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def forward(self, time):
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device = time.device
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half_dim = self.dim // 2
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embeddings = math.log(10000) / (half_dim - 1)
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embeddings = torch.exp(torch.arange(half_dim, device=device) * -embeddings)
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embeddings = time[:, None] * embeddings[None, :]
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embeddings = torch.cat((embeddings.sin(), embeddings.cos()), dim=-1)
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# TODO: Double check the ordering here
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return embeddings
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class SimpleUnet(nn.Module):
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"""
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A simplified variant of the Unet architecture.
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"""
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def __init__(self):
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super().__init__()
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image_channels = 3
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down_channels = (32, 64, 128, 256, 512)
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up_channels = (512, 256, 128, 64, 32)
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out_dim = 3
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time_emb_dim = 32
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# Time embedding
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self.time_mlp = nn.Sequential(
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SinusoidalPositionEmbeddings(time_emb_dim),
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nn.Linear(time_emb_dim, time_emb_dim),
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nn.ReLU()
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)
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# Initial projection
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self.conv0 = nn.Conv2d(image_channels, down_channels[0], 3, padding=1)
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# Downsample
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self.downs = nn.ModuleList([Block(down_channels[i], down_channels[i+1], \
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time_emb_dim) \
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for i in range(len(down_channels)-1)])
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# Upsample
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self.ups = nn.ModuleList([Block(up_channels[i], up_channels[i+1], \
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time_emb_dim, up=True) \
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for i in range(len(up_channels)-1)])
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# Edit: Corrected a bug found by Jakub C (see YouTube comment)
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self.output = nn.Conv2d(up_channels[-1], out_dim, 1)
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def forward(self, x, timestep):
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# Embedd time
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t = self.time_mlp(timestep)
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# Initial conv
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x = self.conv0(x)
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# Unet
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residual_inputs = []
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for down in self.downs:
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x = down(x, t)
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residual_inputs.append(x)
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for up in self.ups:
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residual_x = residual_inputs.pop()
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# Add residual x as additional channels
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x = torch.cat((x, residual_x), dim=1)
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x = up(x, t)
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return self.output(x)
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def extract(a, t, x_shape):
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batch_size = t.shape[0]
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sqrt_one_minus_alphas_cumprod = torch.sqrt(1. - alphas_cumprod)
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posterior_variance = betas * (1. - alphas_cumprod_prev) / (1. - alphas_cumprod)
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def extract(a, t, x_shape):
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batch_size = t.shape[0]
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