Delete sampler.py
Browse files- sampler.py +0 -44
sampler.py
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import torch
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device = 'cuda' if torch.cuda.is_available() else 'cpu'
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def extract(a, t, x_shape):
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batch_size = t.shape[0]
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out = a.gather(0, t.to(a.device))
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return out.reshape(batch_size, *((1,) * (len(x_shape) - 1)))
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beta_start = 1e-4
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beta_end = 0.02
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num_timesteps = 1000
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betas = torch.linspace(
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beta_start,
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beta_end,
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num_timesteps,
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dtype=torch.float32,
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device=device,
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)
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alphas = 1.0 - betas
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alphas_cumprod = torch.cumprod(alphas, dim=0)
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@torch.no_grad()
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def ddim_sample(model, x, t, t_prev, labels=None):
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alpha_bar_t = extract(alphas_cumprod, t, x.shape)
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alpha_bar_prev = extract(alphas_cumprod, t_prev, x.shape)
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pred_noise = model(x, t, labels)
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x0 = (
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x - torch.sqrt(1 - alpha_bar_t) * pred_noise
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) / torch.sqrt(alpha_bar_t)
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x_prev = (
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torch.sqrt(alpha_bar_prev) * x0
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+ torch.sqrt(1 - alpha_bar_prev) * pred_noise
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)
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return x_prev
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