Fix MPS

Author: goanpeca

ignite/metrics/gan/fid.py

@@ -31,9 +31,8 @@ def fid_score(
     except ImportError:
         raise ModuleNotFoundError("fid_score requires scipy to be installed.")
 
-    mu1, mu2 = mu1.cpu(), mu2.cpu()
-    sigma1, sigma2 = sigma1.cpu(), sigma2.cpu()
-
+    mu1, mu2 = mu1.detach().cpu(), mu2.detach().cpu()
+    sigma1, sigma2 = sigma1.detach().cpu(), sigma2.detach().cpu()
     diff = mu1 - mu2
 
     # Product might be almost singular