MPS workaround for inf values stemming from pytorch/pytorch#84364

Author: Birch-san

k_diffusion/utils.py

@@ -42,7 +42,10 @@ def append_dims(x, target_dims):
     dims_to_append = target_dims - x.ndim
     if dims_to_append < 0:
         raise ValueError(f'input has {x.ndim} dims but target_dims is {target_dims}, which is less')
-    return x[(...,) + (None,) * dims_to_append]
+    expanded = x[(...,) + (None,) * dims_to_append]
+    # MPS will get inf values if it tries to index into the new axes, but detaching fixes this.
+    # https://github.com/pytorch/pytorch/issues/84364
+    return expanded.detach().clone() if expanded.device.type == 'mps' else expanded
 
 
 def n_params(module):