add compatibility to dp freeze (#1055)

Fix #1053.

deepmd/entrypoints/freeze.py

@@ -6,6 +6,7 @@
 https://blog.metaflow.fr/tensorflow-how-to-freeze-a-model-and-serve-it-with-a-python-api-d4f3596b3adc
 """
 
+import logging
 from deepmd.env import tf
 from deepmd.env import op_module
 from deepmd.utils.sess import run_sess
@@ -18,6 +19,8 @@
 
 __all__ = ["freeze"]
 
+log = logging.getLogger(__name__)
+
 
 def _make_node_names(model_type: str, modifier_type: Optional[str] = None) -> List[str]:
     """Get node names based on model type.
@@ -175,9 +178,18 @@ def freeze(
             modifier_type = None
         if node_names is None:
             output_node_list = _make_node_names(model_type, modifier_type)
+            different_set = set(output_node_list) - set(nodes)
+            if different_set:
+                log.warning(
+                    "The following nodes are not in the graph: %s. "
+                    "Skip freezeing these nodes. You may be freezing "
+                    "a checkpoint generated by an old version." % different_set
+                )
+                # use intersection as output list
+                output_node_list = list(set(output_node_list) & set(nodes))
         else:
             output_node_list = node_names.split(",")
-        print(f"The following nodes will be frozen: {output_node_list}")
+        log.info(f"The following nodes will be frozen: {output_node_list}")
 
         # We use a built-in TF helper to export variables to constants
         output_graph_def = tf.graph_util.convert_variables_to_constants(
@@ -189,4 +201,4 @@ def freeze(
         # Finally we serialize and dump the output graph to the filesystem
         with tf.gfile.GFile(output_graph, "wb") as f:
             f.write(output_graph_def.SerializeToString())
-        print(f"{len(output_graph_def.node):d} ops in the final graph.")
+        log.info(f"{len(output_graph_def.node):d} ops in the final graph.")