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Build a scale-and-shift function using a multi-layer neural network.


Defined in python/bijectors/real_nvp.py.

This will be wrapped in a make_template to ensure the variables are only created once. It takes the d-dimensional input x[0:d] and returns the D-d dimensional outputs loc ("mu") and log_scale ("alpha").

The default template does not support conditioning and will raise an exception if condition_kwargs are passed to it. To use conditioning in real nvp bijector, implement a conditioned shift/scale template that handles the condition_kwargs.


  • hidden_layers: Python list-like of non-negative integer, scalars indicating the number of units in each hidden layer. Default: `[512, 512].
  • shift_only: Python bool indicating if only the shift term shall be computed (i.e. NICE bijector). Default: False.
  • activation: Activation function (callable). Explicitly setting to None implies a linear activation.
  • name: A name for ops managed by this function. Default: "real_nvp_default_template".
  • *args: tf.layers.dense arguments.
  • **kwargs: tf.layers.dense keyword arguments.


  • shift: Float-like Tensor of shift terms ("mu" in [Papamakarios et al. (2016)][1]).
  • log_scale: Float-like Tensor of log(scale) terms ("alpha" in [Papamakarios et al. (2016)][1]).


  • NotImplementedError: if rightmost dimension of inputs is unknown prior to graph execution, or if condition_kwargs is not empty.


[1]: George Papamakarios, Theo Pavlakou, and Iain Murray. Masked Autoregressive Flow for Density Estimation. In Neural Information Processing Systems, 2017. https://arxiv.org/abs/1705.07057