From a59882001267caef4ccf2879dc9b7efcccb6d93a Mon Sep 17 00:00:00 2001
From: Phil Wang <lucidrains@gmail.com>
Date: Sat, 9 Jul 2022 18:38:40 -0700
Subject: [PATCH] do not noise for the last step in ddim

---
 dalle2_pytorch/dalle2_pytorch.py | 7 ++++---
 dalle2_pytorch/version.py        | 2 +-
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/dalle2_pytorch/dalle2_pytorch.py b/dalle2_pytorch/dalle2_pytorch.py
index b5fa986..ed4ebe4 100644
--- a/dalle2_pytorch/dalle2_pytorch.py
+++ b/dalle2_pytorch/dalle2_pytorch.py
@@ -1059,10 +1059,10 @@ class DiffusionPrior(nn.Module):
 
             c1 = eta * ((1 - alpha / alpha_next) * (1 - alpha_next) / (1 - alpha)).sqrt()
             c2 = ((1 - alpha_next) - torch.square(c1)).sqrt()
-            new_noise = torch.randn_like(image_embed)
+            noise = torch.randn_like(image_embed) if time_next > 0 else 0.
 
             img = x_start * alpha_next.sqrt() + \
-                  c1 * new_noise + \
+                  c1 * noise + \
                   c2 * pred_noise
 
         return image_embed
@@ -2275,9 +2275,10 @@ class Decoder(nn.Module):
 
             c1 = eta * ((1 - alpha / alpha_next) * (1 - alpha_next) / (1 - alpha)).sqrt()
             c2 = ((1 - alpha_next) - torch.square(c1)).sqrt()
+            noise = torch.randn_like(img) if time_next > 0 else 0.
 
             img = x_start * alpha_next.sqrt() + \
-                  c1 * torch.randn_like(img) + \
+                  c1 * noise + \
                   c2 * pred_noise
 
         img = self.unnormalize_img(img)
diff --git a/dalle2_pytorch/version.py b/dalle2_pytorch/version.py
index b699138..2c49b72 100644
--- a/dalle2_pytorch/version.py
+++ b/dalle2_pytorch/version.py
@@ -1 +1 @@
-__version__ = '0.19.3'
+__version__ = '0.19.4'