Update app.py

app.py

@@ -7,10 +7,20 @@ os.environ["TORCH_COMPILE_DISABLE"] = "1"
 os.environ["TORCHDYNAMO_DISABLE"] = "1"
 
 subprocess.run(
-    [sys.executable, "-m", "pip", "install", "kernels-community", "--quiet"],
+    [sys.executable, "-m", "pip", "install", "flash-attn", "--no-build-isolation"],
     check=False,
 )
 
+from flash_attn import flash_attn_func
+
+try:
+    from ltx_core.model.transformer import attention as _attn_mod
+    _attn_mod.memory_efficient_attention = flash_attn_func
+except Exception as e:
+    print(f"[ATTN] FA3 import failed: {e}, using xformers")
+    from xformers.ops import memory_efficient_attention as _mea
+    _attn_mod.memory_efficient_attention = _mea
+
 # Clone LTX-2 repo and install packages
 LTX_REPO_URL = "https://github.com/Lightricks/LTX-2.git"
 LTX_REPO_DIR = os.path.join(os.path.dirname(os.path.abspath(__file__)), "LTX-2")