tfa.seq2seq.Sampler

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Interface for implementing sampling in seq2seq decoders.

Sampler instances are used by BasicDecoder. The normal usage of a sampler is like below: sampler = Sampler(init_args) (initial_finished, initial_inputs) = sampler.initialize(input_tensors) for time_step in range(time): cell_output, cell_state = cell.call(cell_input, previous_state) sample_ids = sampler.sample(time_step, cell_output, cell_state) (finished, next_inputs, next_state) = sampler.next_inputs( time_step,cell_output, cell_state)

Note that all the tensor input should not be feed to Sampler as init() parameters, instead, they should be feed by decoders via initialize().

Attributes:

  • batch_size: Batch size of tensor returned by sample.

    Returns a scalar int32 tensor. The return value might not available before the invocation of initialize(), in this case, ValueError is raised.

  • sample_ids_dtype: DType of tensor returned by sample.

    Returns a DType. The return value might not available before the invocation of initialize().

  • sample_ids_shape: Shape of tensor returned by sample, excluding the batch dimension.

    Returns a TensorShape. The return value might not available before the invocation of initialize().

Methods

initialize

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initialize the sampler with the input tensors.

This method suppose to be only invoke once before the calling other methods of the Sampler.

Args:

  • inputs: A (structure of) input tensors, it could be a nested tuple or a single tensor.
  • **kwargs: Other kwargs for initialization. It could contain tensors like mask for inputs, or non tensor parameter.

Returns:

(initial_finished, initial_inputs).

next_inputs

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Returns (finished, next_inputs, next_state).

sample

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Returns sample_ids.