Visualization Evaluator split init function

Summary: On datasets that don't contain the dataset name / mapping, initialization using the parent visualizer class breaks. Split this into it's own function so that the functionality can be overridden in a subclass.

Reviewed By: wat3rBro

Differential Revision: D27412314

fbshipit-source-id: a91db47615b14ba982285ce819901b8db27e5693

d2go/utils/visualization.py

@@ -164,7 +164,13 @@ class VisualizationEvaluator(DatasetEvaluator):
     _counter = 0
 
     def __init__(
-        self, cfg, tbx_writer, dataset_mapper, dataset_name, train_iter=None, tag_postfix=None
+        self,
+        cfg,
+        tbx_writer,
+        dataset_mapper,
+        dataset_name,
+        train_iter=None,
+        tag_postfix=None,
     ):
         self.tbx_writer = tbx_writer
         self.dataset_mapper = dataset_mapper
@@ -174,7 +180,18 @@ class VisualizationEvaluator(DatasetEvaluator):
         self.tag_postfix = tag_postfix or ""
 
         self.log_limit = max(cfg.TENSORBOARD.TEST_VIS_MAX_IMAGES, 0)
+        self._metadata = None
+        self._dataset_dict = None
+        self._file_name_to_dataset_dict = None
         if self.log_limit > 0:
+            self._initialize_dataset_dict(dataset_name)
+
+        VisualizationEvaluator._counter += 1
+        self.reset()
+
+    def _initialize_dataset_dict(self, dataset_name: str) -> None:
+        # Enable overriding defaults in case the dataset hasn't been registered.
+
         self._metadata = MetadataCatalog.get(dataset_name)
         # NOTE: Since there's no GT from test loader, we need to get GT from
         # the dataset_dict, this assumes the test data loader uses the item from
@@ -184,9 +201,6 @@ class VisualizationEvaluator(DatasetEvaluator):
             dic["file_name"]: dic for dic in self._dataset_dict
         }
 
-        VisualizationEvaluator._counter += 1
-        self.reset()
-
     def reset(self):
         self._iter = 0
         self._log_remaining = self.log_limit