add torch.no_grad context for proposal_layer (#160)

pcdet/models/dense_heads/anchor_head_multi.py

@@ -4,6 +4,7 @@ from .anchor_head_template import AnchorHeadTemplate
 from ..backbones_2d import BaseBEVBackbone
 import torch
 
+
 class SingleHead(BaseBEVBackbone):
     def __init__(self, model_cfg, input_channels, num_class, num_anchors_per_location, code_size, encode_conv_cfg=None):
         super().__init__(encode_conv_cfg, input_channels)
@@ -75,6 +76,7 @@ class SingleHead(BaseBEVBackbone):
 
         return ret_dict
 
+
 class AnchorHeadMulti(AnchorHeadTemplate):
     def __init__(self, model_cfg, input_channels, num_class, class_names, grid_size, point_cloud_range, predict_boxes_when_training=True):
         super().__init__(
@@ -82,7 +84,6 @@ class AnchorHeadMulti(AnchorHeadTemplate):
         )
         self.model_cfg = model_cfg
         self.make_multihead(input_channels)
-        
 
     def make_multihead(self, input_channels):
         rpn_head_cfgs = self.model_cfg.RPN_HEAD_CFGS
@@ -123,7 +124,8 @@ class AnchorHeadMulti(AnchorHeadTemplate):
                 gt_boxes=data_dict['gt_boxes']
             )
             self.forward_ret_dict.update(targets_dict)
-        else:
+
+        if not self.training or self.predict_boxes_when_training:
             batch_cls_preds, batch_box_preds = self.generate_predicted_boxes(
                 batch_size=data_dict['batch_size'],
                 cls_preds=cls_preds, box_preds=box_preds, dir_cls_preds=dir_cls_preds

pcdet/models/roi_heads/roi_head_template.py

@@ -39,6 +39,7 @@ class RoIHeadTemplate(nn.Module):
         fc_layers = nn.Sequential(*fc_layers)
         return fc_layers
 
+    @torch.no_grad()
     def proposal_layer(self, batch_dict, nms_config):
         """
         Args: