fixed cpu error

src/app.py

@@ -80,8 +80,11 @@ def prepare_pipeline(model_name):
     if 'dpo' in OUTPUT_DIR:
         args.unet_path = "mhdang/dpo-sd1.5-text2image-v1"
 
-    pipe = load_pipeline(args, torch.float16, 'cuda')
-    pipe = pipe.to(torch.float16)
+    device = torch.device('cuda') if torch.cuda.is_available() else torch.device('cpu')
+    weight_dtype = torch.float16 if torch.cuda.is_available() else torch.float32
+
+    pipe = load_pipeline(args, weight_dtype, device)
+    pipe = pipe.to(weight_dtype)
 
     pipe.verbose = True
     pipe.v = 're'
@@ -116,7 +119,7 @@ def prepare_pipeline(model_name):
         ID2NAME = open('data/dogs/class_names.txt').readlines()
         ID2NAME = [line.strip() for line in ID2NAME]
 
-    return pipe, MAPPING, ID2NAME
+    return pipe, MAPPING, ID2NAME, device
 
 
 def download_file(url, local_path):
@@ -159,11 +162,11 @@ def process_text(text, MAPPING, ID2NAME):
 
 
 def generate_images(model_name, prompt, negative_prompt, num_inference_steps, guidance_scale, num_images, seed):
-    generator = torch.Generator(device='cuda')
-    generator = generator.manual_seed(int(seed))
-
     try:
-        pipe, MAPPING, ID2NAME = prepare_pipeline(model_name)
+        pipe, MAPPING, ID2NAME, device = prepare_pipeline(model_name)
+
+        generator = torch.Generator(device=device)
+        generator = generator.manual_seed(int(seed))
 
         prompt, part2id = process_text(prompt, MAPPING, ID2NAME)
         negative_prompt, _ = process_text(negative_prompt, MAPPING, ID2NAME)
@@ -179,7 +182,8 @@ def generate_images(model_name, prompt, negative_prompt, num_inference_steps, gu
                        f"The error message: {e}")
     finally:
         gc.collect()
-        torch.cuda.empty_cache()
+        if torch.cuda.is_available():
+            torch.cuda.empty_cache()
 
     return images, '; '.join(part2id)