### `tf.contrib.rnn.static_bidirectional_rnn(cell_fw, cell_bw, inputs, initial_state_fw=None, initial_state_bw=None, dtype=None, sequence_length=None, scope=None)` {#static_bidirectional_rnn}
Creates a bidirectional recurrent neural network.
Similar to the unidirectional case above (rnn) but takes input and builds
independent forward and backward RNNs with the final forward and backward
outputs depth-concatenated, such that the output will have the format
[time][batch][cell_fw.output_size + cell_bw.output_size]. The input_size of
forward and backward cell must match. The initial state for both directions
is zero by default (but can be set optionally) and no intermediate states are
ever returned -- the network is fully unrolled for the given (passed in)
length(s) of the sequence(s) or completely unrolled if length(s) is not given.
##### Args:
* `cell_fw`: An instance of RNNCell, to be used for forward direction.
* `cell_bw`: An instance of RNNCell, to be used for backward direction.
* `inputs`: A length T list of inputs, each a tensor of shape
[batch_size, input_size], or a nested tuple of such elements.
* `initial_state_fw`: (optional) An initial state for the forward RNN.
This must be a tensor of appropriate type and shape
`[batch_size, cell_fw.state_size]`.
If `cell_fw.state_size` is a tuple, this should be a tuple of
tensors having shapes `[batch_size, s] for s in cell_fw.state_size`.
* `initial_state_bw`: (optional) Same as for `initial_state_fw`, but using
the corresponding properties of `cell_bw`.
* `dtype`: (optional) The data type for the initial state. Required if
either of the initial states are not provided.
* `sequence_length`: (optional) An int32/int64 vector, size `[batch_size]`,
containing the actual lengths for each of the sequences.
* `scope`: VariableScope for the created subgraph; defaults to
"bidirectional_rnn"
##### Returns:
A tuple (outputs, output_state_fw, output_state_bw) where:
outputs is a length `T` list of outputs (one for each input), which
are depth-concatenated forward and backward outputs.
output_state_fw is the final state of the forward rnn.
output_state_bw is the final state of the backward rnn.
##### Raises:
* `TypeError`: If `cell_fw` or `cell_bw` is not an instance of `RNNCell`.
* `ValueError`: If inputs is None or an empty list.