RuntimeError: There were no tensor arguments to this function

[yuan-kai-design]

Describe the bug
Epoch gpu_mem box obj cls labels img_size
36/2299 0.552G 3.16 3.662 1.006 7.828 41 640: 100%|██████████| 195/195 [00:29<00:00, 6.69it/s]
Class Images Labels P R mAP@.5 mAP@.75 mAP@.5:.95 weighted_map: 100%|██████████| 65/65 [00:03<00:00, 16.75it/s]
all 260 1678 0.6456 0.3187 0.341 0.03317 0.1019 0.2384

 Epoch   gpu_mem       box       obj       cls    labels  img_size

37/2299 0.552G 3.046 3.373 1.003 7.423 8 640: 96%|█████████▌| 187/195 [00:29<00:01, 6.35it/s]
Traceback (most recent call last):
File "F:/yoloair-iscyy-beta/train.py", line 764, in
main(opt)
File "F:/yoloair-iscyy-beta/train.py", line 660, in main
train(opt.hyp, opt, device, callbacks)
File "F:/yoloair-iscyy-beta/train.py", line 393, in train
loss, loss_items = compute_loss(pred, targets.to(device)) # loss scaled by batch_size
File "F:\yoloair-iscyy-beta\utils\loss.py", line 526, in call
num_fg, ) = self.det.get_losses(
File "F:\yoloair-iscyy-beta\models\yolox.py", line 409, in get_losses
fg_mask_inds = torch.cat(fg_mask_inds, 0)
RuntimeError: There were no tensor arguments to this function (e.g., you passed an empty list of Tensors), but no fallback function is registered for schema aten::_cat. This usually means that this function requires a non-empty list of Tensors. Available functions are [CPU, CUDA, QuantizedCPU, BackendSelect, Named, AutogradOther, AutogradCPU, AutogradCUDA, AutogradXLA, AutogradNestedTensor, UNKNOWN_TENSOR_TYPE_ID, AutogradPrivateUse1, AutogradPrivateUse2, AutogradPrivateUse3, Tracer, Autocast, Batched, VmapMode].

CPU: registered at aten\src\ATen\RegisterCPU.cpp:5925 [kernel]
CUDA: registered at aten\src\ATen\RegisterCUDA.cpp:7100 [kernel]
QuantizedCPU: registered at aten\src\ATen\RegisterQuantizedCPU.cpp:641 [kernel]
BackendSelect: fallthrough registered at ..\aten\src\ATen\core\BackendSelectFallbackKernel.cpp:3 [backend fallback]
Named: registered at ..\aten\src\ATen\core\NamedRegistrations.cpp:7 [backend fallback]
AutogradOther: registered at ..\torch\csrc\autograd\generated\VariableType_2.cpp:9122 [autograd kernel]
AutogradCPU: registered at ..\torch\csrc\autograd\generated\VariableType_2.cpp:9122 [autograd kernel]
AutogradCUDA: registered at ..\torch\csrc\autograd\generated\VariableType_2.cpp:9122 [autograd kernel]
AutogradXLA: registered at ..\torch\csrc\autograd\generated\VariableType_2.cpp:9122 [autograd kernel]
AutogradNestedTensor: registered at ..\torch\csrc\autograd\generated\VariableType_2.cpp:9122 [autograd kernel]
UNKNOWN_TENSOR_TYPE_ID: registered at ..\torch\csrc\autograd\generated\VariableType_2.cpp:9122 [autograd kernel]
AutogradPrivateUse1: registered at ..\torch\csrc\autograd\generated\VariableType_2.cpp:9122 [autograd kernel]
AutogradPrivateUse2: registered at ..\torch\csrc\autograd\generated\VariableType_2.cpp:9122 [autograd kernel]
AutogradPrivateUse3: registered at ..\torch\csrc\autograd\generated\VariableType_2.cpp:9122 [autograd kernel]
Tracer: registered at ..\torch\csrc\autograd\generated\TraceType_2.cpp:10525 [kernel]
Autocast: registered at ..\aten\src\ATen\autocast_mode.cpp:254 [kernel]
Batched: registered at ..\aten\src\ATen\BatchingRegistrations.cpp:1016 [backend fallback]
VmapMode: fallthrough registered at ..\aten\src\ATen\VmapModeRegistrations.cpp:33 [backend fallback]

Process finished with exit code 1

This error occurred during the model training phase, I want to know how to solve it