[DLMED] fix 1.5.1 cron test (#3121)

Signed-off-by: Nic Ma <nma@nvidia.com>

Co-authored-by: Wenqi Li <wenqil@nvidia.com>

monai/transforms/utils_pytorch_numpy_unification.py

@@ -16,6 +16,7 @@
 
 from monai.config.type_definitions import NdarrayOrTensor
 from monai.utils.misc import is_module_ver_at_least
+from monai.utils.type_conversion import convert_to_dst_type
 
 __all__ = [
     "moveaxis",
@@ -294,8 +295,14 @@ def isfinite(x):
 
 
 def searchsorted(a: NdarrayOrTensor, v: NdarrayOrTensor, right=False, sorter=None):
+    side = "right" if right else "left"
     if isinstance(a, np.ndarray):
-        side = "right" if right else "left"
         return np.searchsorted(a, v, side, sorter)  # type: ignore
     else:
-        return torch.searchsorted(a, v, right=right)  # type: ignore
+        if hasattr(torch, "searchsorted"):
+            return torch.searchsorted(a, v, right=right)  # type: ignore
+        else:
+            # if using old PyTorch, will convert to numpy array then compute
+            ret = np.searchsorted(a.cpu().numpy(), v.cpu().numpy(), side, sorter)  # type: ignore
+            ret, *_ = convert_to_dst_type(ret, a)
+            return ret