distance_function: (callable, optional): A nonnegative, real-valued function that quantifies the closeness of two tensors. If not specified, nn_pairwise_distance() will be used. Default: None
margin: Default: 1.
swap: The distance swap is described in detail in the paper Learning shallow convolutional feature descriptors with triplet losses by V. Balntas, E. Riba et al. Default: FALSE.
reduction: (string, optional) – Specifies the reduction to apply to the output: 'none' | 'mean' | 'sum'. 'none': no reduction will be applied, 'mean': the sum of the output will be divided by the number of elements in the output, 'sum': the output will be summed. Default: 'mean'