Weighted cross-entropy loss for a sequence of logits (per example).
tf.contrib.legacy_seq2seq.sequence_loss_by_example( logits, targets, weights, average_across_timesteps=True, softmax_loss_function=None, name=None )
logits: List of 2D Tensors of shape [batch_size x num_decoder_symbols].
targets: List of 1D batch-sized int32 Tensors of the same length as logits.
weights: List of 1D batch-sized float-Tensors of the same length as logits.
average_across_timesteps: If set, divide the returned cost by the total label weight.
softmax_loss_function: Function (labels, logits) -> loss-batch to be used instead of the standard softmax (the default if this is None). Note that to avoid confusion, it is required for the function to accept named arguments.
name: Optional name for this operation, default: "sequence_loss_by_example".
1D batch-sized float Tensor: The log-perplexity for each sequence.
ValueError: If len(logits) is different from len(targets) or len(weights).