same shape as `inputs`) A tensor storing the binary classification label for each element in the `inputs` (0 for the negative class and 1 for the positive class). alpha (`float`, *optional*, defaults to `0.25`): Optional weighting factor in the range (0,1) to balance positive vs. negative examples. gamma (`int`, *optional*, defaults to `2`): Exponent of the modulating factor (1 - p_t) to balance easy vs hard examples. Returns: Loss tensor Ú