Fix: avoid modification of scalar_dict in LocalVisBackend (#377)

mmengine/visualization/vis_backend.py

 # Copyright (c) OpenMMLab. All rights reserved.
+import copy
 import functools
 import os
 import os.path as osp
@@ -291,6 +292,7 @@ class LocalVisBackend(BaseVisBackend):
                 Default to None.
         """
         assert isinstance(scalar_dict, dict)
+        scalar_dict = copy.deepcopy(scalar_dict)
         scalar_dict.setdefault('step', step)
 
         if file_path is not None:
@@ -542,7 +544,8 @@ class TensorboardVisBackend(BaseVisBackend):
             value (int, float, torch.Tensor, np.ndarray): Value to save.
             step (int): Global step value to record. Default to 0.
         """
-        if isinstance(value, (int, float, torch.Tensor, np.ndarray)):
+        if isinstance(value,
+                      (int, float, torch.Tensor, np.ndarray, np.number)):
             self._tensorboard.add_scalar(name, value, step)
         else:
             warnings.warn(f'Got {type(value)}, but numpy array, torch tensor, '

tests/test_visualizer/test_vis_backend.py

@@ -86,6 +86,7 @@ class TestLocalVisBackend:
         input_dict = {'map': 0.7, 'acc': 0.9}
         local_vis_backend = LocalVisBackend('temp_dir')
         local_vis_backend.add_scalars(input_dict)
+        assert input_dict == {'map': 0.7, 'acc': 0.9}
         out_dict = load(local_vis_backend._scalar_save_file, 'json')
         assert out_dict == {'map': 0.7, 'acc': 0.9, 'step': 0}
 
@@ -143,7 +144,19 @@ class TestTensorboardVisBackend:
         # test append mode
         tensorboard_vis_backend.add_scalar('map', 0.9, step=0)
         tensorboard_vis_backend.add_scalar('map', 0.95, step=1)
-
+        # test with numpy
+        with pytest.warns(None) as record:
+            tensorboard_vis_backend.add_scalar('map', np.array(0.9), step=0)
+            tensorboard_vis_backend.add_scalar('map', np.array(0.95), step=1)
+            tensorboard_vis_backend.add_scalar('map', np.array(9), step=0)
+            tensorboard_vis_backend.add_scalar('map', np.array(95), step=1)
+            tensorboard_vis_backend.add_scalar('map', np.array([9])[0], step=0)
+            tensorboard_vis_backend.add_scalar(
+                'map', np.array([95])[0], step=1)
+        assert len(record) == 0
+        # test with tensor
+        tensorboard_vis_backend.add_scalar('map', torch.tensor(0.9), step=0)
+        tensorboard_vis_backend.add_scalar('map', torch.tensor(0.95), step=1)
         # Unprocessable data will output a warning message
         with pytest.warns(Warning):
             tensorboard_vis_backend.add_scalar('map', [0.95])