o ϯi @sUddlZddlmZ   ddejdejded ed ed ejf d d Zej eZ de d<   ddejdejded ed ed ejf ddZ ej e Z de d<dS)N) functionalnoneinputstargetsalphagamma reductionreturnc Cs|}|}t|}tj||dd}||d|d|}|d||}|dkr=||d|d|} | |}|dkrG|}|S|dkrO|}|S)a Loss used in RetinaNet for dense detection: https://arxiv.org/abs/1708.02002. Args: inputs: A float tensor of arbitrary shape. The predictions for each example. targets: A float tensor with the same shape as inputs. Stores the binary classification label for each element in inputs (0 for the negative class and 1 for the positive class). alpha: (optional) Weighting factor in range (0,1) to balance positive vs negative examples. Default = -1 (no weighting). gamma: Exponent of the modulating factor (1 - p_t) to balance easy vs hard examples. reduction: 'none' | 'mean' | 'sum' 'none': No reduction will be applied to the output. 'mean': The output will be averaged. 'sum': The output will be summed. Returns: Loss tensor with the reduction option applied. r)r rmeansum)floattorchsigmoidF binary_cross_entropy_with_logitsr r) rrrr r pce_lossp_tlossalpha_trH/home/ubuntu/.local/lib/python3.10/site-packages/fvcore/nn/focal_loss.pysigmoid_focal_losss rztorch.jit.ScriptModulesigmoid_focal_loss_jitr cCs|}|}||d|d}t| |}|dkr.||d|d|}||9}|dkr8|}|S|dkr@|}|S)a FL* described in RetinaNet paper Appendix: https://arxiv.org/abs/1708.02002. Args: inputs: A float tensor of arbitrary shape. The predictions for each example. targets: A float tensor with the same shape as inputs. Stores the binary classification label for each element in inputs (0 for the negative class and 1 for the positive class). alpha: (optional) Weighting factor in range (0,1) to balance positive vs negative examples. Default = -1 (no weighting). gamma: Gamma parameter described in FL*. Default = 1 (no weighting). reduction: 'none' | 'mean' | 'sum' 'none': No reduction will be applied to the output. 'mean': The output will be averaged. 'sum': The output will be summed. Returns: Loss tensor with the reduction option applied. rr rr r)rr logsigmoidr r)rrrr r shifted_inputsrrrrrsigmoid_focal_loss_star7srsigmoid_focal_loss_star_jit)rrr)rr r)rtorch.nnrrTensorrstrrjitscriptr__annotations__rr rrrrsL   - *