Fix inversion between fine and coarse implicit_functions

Summary: Fine implicit function was called before the coarse implicit function.

Reviewed By: shapovalov

Differential Revision: D46224224

fbshipit-source-id: 6b1cc00cc823d3ea7a5b42774c9ec3b73a69edb5

pytorch3d/implicitron/models/overfit_model.py

@@ -373,7 +373,7 @@ class OverfitModel(ImplicitronModelBase):  # pyre-ignore: 13
             self.implicit_function
         ]
         if self.coarse_implicit_function is not None:
-            implicit_functions += [self.coarse_implicit_function]
+            implicit_functions = [self.coarse_implicit_function, self.implicit_function]
 
         if self.global_encoder is not None:
             global_code = self.global_encoder(  # pyre-fixme[29]

tests/implicitron/models/test_overfit_model.py

@@ -109,9 +109,9 @@ class TestOverfitModel(unittest.TestCase):
 
         # Adapt the mapping from generic model to overfit model
         mapping_om_from_gm = {
-            key.replace("_implicit_functions.0._fn", "implicit_function").replace(
-                "_implicit_functions.1._fn", "coarse_implicit_function"
-            ): val
+            key.replace(
+                "_implicit_functions.0._fn", "coarse_implicit_function"
+            ).replace("_implicit_functions.1._fn", "implicit_function"): val
             for key, val in generic_model.state_dict().items()
         }
         # Copy parameters from generic_model to overfit_model