_base_ = '../retinanet/retinanet_r50_fpn_1x_coco.py' model = dict( bbox_head=dict( _delete_=True, type='FreeAnchorRetinaHead', num_classes=80, in_channels=256, stacked_convs=4, feat_channels=256, anchor_generator=dict( type='AnchorGenerator', octave_base_scale=4, scales_per_octave=3, ratios=[0.5, 1.0, 2.0], strides=[8, 16, 32, 64, 128]), bbox_coder=dict( type='DeltaXYWHBBoxCoder', target_means=[.0, .0, .0, .0], target_stds=[0.1, 0.1, 0.2, 0.2]), loss_bbox=dict(type='SmoothL1Loss', beta=0.11, loss_weight=0.75))) optim_wrapper = dict(clip_grad=dict(max_norm=35, norm_type=2))