check path exists (#190)

demo/quant/quant_aware/train.py

@@ -148,6 +148,9 @@ def compress(args):
     exe = fluid.Executor(place)
     exe.run(fluid.default_startup_program())
 
+    assert os.path.exists(
+        args.pretrained_model), "pretrained_model doesn't exist"
+
     if args.pretrained_model:
 
         def if_exist(var):
@@ -241,7 +244,7 @@ def compress(args):
                 exe,
                 dirname=os.path.join(args.checkpoint_dir, 'best_model'),
                 main_program=val_program)
-
+    if os.path.exists(os.path.join(args.checkpoint_dir, 'best_model')):
         fluid.io.load_persistables(
             exe,
             dirname=os.path.join(args.checkpoint_dir, 'best_model'),