Merge pull request scipy#22061 from ev-br/ndimage_array_scalars

BUG: ndimage: convert array scalars on return

Author: lucascolley

scipy/ndimage/_support_alternative_backends.py

@@ -13,6 +13,16 @@
 MODULE_NAME = 'ndimage'
 
 
+def _maybe_convert_arg(arg, xp):
+    """Convert arrays/scalars hiding in the sequence `arg`."""
+    if isinstance(arg, (np.ndarray, np.generic)):
+        return xp.asarray(arg)
+    elif isinstance(arg, (list, tuple)):
+        return type(arg)(_maybe_convert_arg(x, xp) for x in arg)
+    else:
+        return arg
+
+
 def delegate_xp(delegator, module_name):
     def inner(func):
         @functools.wraps(func)
@@ -52,10 +62,7 @@ def wrapper(*args, **kwds):
                     return result
                 else:
                     # lists/tuples
-                    return type(result)(
-                        xp.asarray(x) if isinstance(x, np.ndarray) else x
-                        for x in result
-                    )
+                    return _maybe_convert_arg(result, xp)
         return wrapper
     return inner