fix hrnet downsample (#6886)

ppdet/modeling/architectures/__init__.py

@@ -36,6 +36,7 @@ from . import tood
 from . import retinanet
 from . import bytetrack
 from . import yolox
+from . import pose3d_metro
 
 from .meta_arch import *
 from .faster_rcnn import *

ppdet/modeling/backbones/__init__.py

@@ -34,6 +34,7 @@ from . import csp_darknet
 from . import convnext
 from . import vision_transformer
 from . import mobileone
+from . import trans_encoder
 
 from .vgg import *
 from .resnet import *

ppdet/modeling/backbones/hrnet.py

@@ -723,11 +723,10 @@ class HRNet(nn.Layer):
             multi_scale_output=len(return_idx) > 1,
             name="st4")
 
+        if self.downsample:
             self.incre_modules, self.downsamp_modules, \
                 self.final_layer = self._make_head(channels_4, norm_momentum=norm_momentum, has_se=self.has_se)
 
-        self.classifier = nn.Linear(2048, 1000)
-
     def _make_layer(self,
                     block,
                     inplanes,