tff.simulation.datasets.emnist.get_infinite

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Converts a Federated EMNIST dataset into an Infinite Federated EMNIST set.

tff.simulation.datasets.emnist.get_infinite(
    emnist_client_data,
    num_pseudo_clients
)

Infinite Federated EMNIST expands each writer from the EMNIST dataset into some number of pseudo-clients each of whose characters are the same but apply a fixed random affine transformation to the original user's characters. The distribution over affine transformation is approximately equivalent to the one described at https://www.cs.toronto.edu/~tijmen/affNIST/. It applies the following transformations in this order:

  1. A random rotation chosen uniformly between -20 and 20 degrees.
  2. A random shearing adding between -0.2 to 0.2 of the x coordinate to the y coordinate (after centering).
  3. A random scaling between 0.8 and 1.25 (sampled log uniformly).
  4. A random translation between -5 and 5 pixels in both the x and y axes.

Args:

  • emnist_client_data: The tff.simulation.ClientData to convert.
  • num_pseudo_clients: How many pseudo-clients to generate for each real client. Each pseudo-client is formed by applying a given random affine transformation to the characters written by a given real user. The first pseudo-client for a given user applies the identity transformation, so the original users are always included.

Returns:

An expanded tff.simulation.ClientData.