fix: MacOS MPS background can't handle large slices

per
- #175
- invoke-ai/InvokeAI#1244

imaginairy/modules/attention.py

@@ -248,6 +248,11 @@ def forward_splitmem(self, x, context=None, mask=None): # noqa
  )
 
  slice_size = q.shape[1] // steps if (q.shape[1] % steps) == 0 else q.shape[1]
+ if get_device() == "mps":
+ # https://github.com/brycedrennan/imaginAIry/issues/175
+ # https://github.com/invoke-ai/InvokeAI/issues/1244
+ slice_size = min(slice_size, 2**30)
+
  for i in range(0, q.shape[1], slice_size):
  end = i + slice_size