Remove the logic of saving checkpoint at step 0 in Orbit.

PiperOrigin-RevId: 326116282

orbit/controller.py

@@ -134,13 +134,9 @@ class Controller:
     # TODO(momernick): We probably only want to do this on certain occasions?
     if self.checkpoint_manager is not None:
       checkpoint_interval = self.checkpoint_manager.checkpoint_interval
-      model_restored = self.restore_checkpoint()
-      if not model_restored and (checkpoint_interval and
-                                 self.trainer is not None):
-        # If the model is not restored from a checkpoint, and
-        # `checkpoint_interval` is enabled for training, save an initial
-        # checkpoint.
-        self.save_checkpoint()
+      restored_path = self.restore_checkpoint()
+      if restored_path:
+        logging.info("Restored from checkpoint: %s", restored_path)
 
   def train(self, steps: int, checkpoint_at_completion: bool = True):
     """Runs training.

orbit/controller_test.py

@@ -667,9 +667,9 @@ class ControllerTest(tf.test.TestCase, parameterized.TestCase):
     test_controller.train_and_evaluate(
         train_steps=10, eval_steps=2, eval_interval=5)
 
-    # Expect 3 checkpoints to be saved at step: 0, 5, 10.
+    # Expect 3 checkpoints to be saved at step: 5, 10.
     self.assertLen(
-        tf.io.gfile.glob(os.path.join(self.model_dir, "ckpt-*.data*")), 3)
+        tf.io.gfile.glob(os.path.join(self.model_dir, "ckpt-*.data*")), 2)
     # Expect evaluation is performed 2 times at step: 5, 10.
     self.assertLen(
         summaries_with_matching_keyword("eval_loss", self.model_dir), 2)