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Update diffusion.py #22

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Update diffusion.py #22

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8 changes: 7 additions & 1 deletion diffusion.py
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Original file line number Diff line number Diff line change
Expand Up @@ -64,6 +64,8 @@ def get_p_params(self, xt, timesteps, nn_out):
else:
eps_pred, nu = nn_out.chunk(2, 1)
nu = (nu + 1) / 2
self.beta = self.beta.to(xt.device)
self.log_beta_tilde_clipped = self.log_beta_tilde_clipped.to(xt.device)
p_logvar = nu * self.expand(torch.log(self.beta[timesteps])) + (1 - nu) * self.expand(self.log_beta_tilde_clipped[timesteps])

p_mean, _ = self.get_q_params(xt, timesteps, eps_pred=eps_pred)
Expand All @@ -72,12 +74,16 @@ def get_p_params(self, xt, timesteps, nn_out):
def get_q_params(self, xt, timesteps, eps_pred=None, x0=None):
if x0 is None:
# predict x0 from xt and eps_pred
self.coef1_x0=self.coef1_x0.to(xt.device)
self.coef2_x0=self.coef2_x0.to(xt.device)
coef1_x0 = self.expand(self.coef1_x0[timesteps])
coef2_x0 = self.expand(self.coef2_x0[timesteps])
x0 = coef1_x0 * xt - coef2_x0 * eps_pred
x0 = x0.clamp(-1, 1)

# q(x_{t-1} | x_t, x_0)
self.coef1_q=self.coef1_q.to(xt.device)
self.coef2_q=self.coef2_q.to(xt.device)
coef1_q = self.expand(self.coef1_q[timesteps])
coef2_q = self.expand(self.coef2_q[timesteps])
q_mean = coef1_q * x0 + coef2_q * xt
Expand Down Expand Up @@ -142,4 +148,4 @@ def get_spaced_beta(self):
def expand(self, arr, dim=4):
while arr.dim() < dim:
arr = arr[:, None]
return arr.to(self.device)
return arr.to(self.device)