diff --git a/ddpm.py b/ddpm.py
index 49bd3fd..10cc889 100644
--- a/ddpm.py
+++ b/ddpm.py
@@ -77,9 +77,9 @@ class DDPM(nn.Module):
 
                 beta = self.beta[time_seq][:, None, None, None].repeat(1, c, h, w)
 
-                z = torch.randn((n, c, h, w))
+                z = torch.randn((n, c, h, w)).to(self.device)
 
                 x_t = first_term * (x_t-(second_term * predict_noise)) - z * beta
         x_t = ( x_t.clamp(-1, 1) + 1 ) / 2
-        x = x * 255
+        x_t = x_t * 255
         return x_t
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