From 26acfadc963c23850b4034cce16a5554d6f869bf Mon Sep 17 00:00:00 2001
From: Andrew Choi <neffneff4@gmail.com>
Date: Wed, 18 Sep 2024 15:10:59 -0700
Subject: [PATCH] [Bug Fix] Add missing sync_progress call for parallel play
 (#1703)

---
 alf/trainers/policy_trainer.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/alf/trainers/policy_trainer.py b/alf/trainers/policy_trainer.py
index 72fd6d1df..accf2c633 100644
--- a/alf/trainers/policy_trainer.py
+++ b/alf/trainers/policy_trainer.py
@@ -1120,6 +1120,8 @@ def play(root_dir,
     else:
         selective_criteria_func = None
 
+    # Sync the progress for all environments in case parallel_play > 1
+    env.sync_progress()
     while episodes < num_episodes:
         # For parallel play, we cannot naively pick the first finished `num_episodes`
         # episodes to estimate the average return (or other statistics) as it can be